2003-2007 Cummins No Start? No Problem!

 

We get a lot of calls on a daily basis with customers trying to diagnose some type of issue with their truck, and once diagnosed, with recommendations for products or procedures to remedy the issue.  We must have developed quite a name for ourselves over the years, as frequently we even get calls from shops that are scratching their heads, hoping we have the golden ticket, and fortunately, we usually do!  One of the most common calls we get are from customers with a 2003-2007 Cummins that have developed either a hard start or no start condition.  In order to help out, we had our Assistant Sales Manager, Tyler Lucas, put together this step by step tutorial that you will hopefully find insightful.   Tyler has been elbow deep in diesel engines for years, especially Cummins, so he is a wealth of information when trying to cure a plagued engine.

The very first thing that needs to be checked is battery voltage.  When I say battery voltage, I am not talking about just getting a voltmeter and putting it on the positive and negative posts, as you will only get what’s called a surface charge, which won’t tell you what’s actually going on when the battery is under load (i.e. cranking).  It is very common to have a battery read around twelve volts on a surface charge, but then drop well below nine (the minimum voltage to allow for cranking on 2003 to current Cummins) when under load.  Overall, make sure that when you test the battery, FASS Titaniumyou are doing so under load by cranking the engine and watching the voltmeter.

Let’s now say your batteries are good.  You then ask yourself, “Tyler, what now?”  Don’t worry sad no start truck, we’ve got your back!  Let’s now dive into the fuel system.  First off, let’s get this out of the way, Ram trucks NEVER had the best luck with lift pumps.  A lack of lift pump flow will not only cause a no start issue, but depending on how it failed, can cause other issues that we will discuss further into this post.  The factory lift pumps on the 2003-2007 Cummins produce a dismal 10-11.5 PSI at idle.  But unfortunately, due to these pumps’ inability to actually produce volume, the pressure drops off considerably as load increases.  And remember, while pressure is definitely an important factor as this is the rate at which fuel is dispensed, volume is equally, if not more important, as it’s the amount of fuel.  This drop in pressure is even greater when fueling modifications and upgrades are added, such as programmers, upgraded larger displacement injectors, and higher volume injection pumps, because guess what, they are all demanding additional fueling for increased performance.  When you start going below 5 PSI, you are not supplying the injection pump with enough fuel to properly drive the injectors, and at the very least, you will experience a loss of power and fuel economy.  Some customers will notice the truck “falling on its face” or flat lining with power as the pump simply cannot supply any more fuel.  After time, the pump will just stop working due to being over stressed and constantly running at maximum output.  And this is exactly what we will be testing for next, the health of the lift pump.  The best way to check your fuel pressure is to install an inline pressure gauge before the injection pump.  But we understand that in many instances when your truck won’t start, you simply don’t have the time or resources to collect the parts and tools to accomplish this.  So we have an alternative method for you by checking the general volume output of the pump.  In order to do this, remove the fuel supply line before it connects to the injection pump and place the open end into a bucket under the truck.  Next, hop in your truck, and “bump” the key.  When I say bump the key, just turn the key to crank the engine for a second in order to engage the pump.  At this point, you should hear the pump run the duration of its  cycle.  For reference, the 2003-2004.5 trucks came equipped with a block mounted lift pump and the 2005-2007 trucks came from the factory with an in-tank lift pump, yet many of the 2003-2004.5 trucks were later retrofitted with this same in-tank design.  This will give you a gauge on where to listen for the “hum” of the electric motor on the pump.  Once you’ve bumped the key, presuming the pump is operating normally, you should see fuel dumping into the bucket.  However, if no fuel comes out, then it’s safe to assume that this is the culprit of your no start issue.  In order to correct, you’ll need to replace the lift pump, and no better time to upgrade than now.  Our preferred brands of aftermarket lift pumps are FASS and AirDog, simply because they have options for stock to fully modified engines, offer filtration that is far superior to stock for increased protection, and come standard with a lifetime warranty.  Out of those manufacturers, our most popular models are without a doubt the FASS Titanium and AirDog II-4G.  For most trucks, even slightly modified, a volume of 95 or 100GPH is ample to properly supply the injection pump for a lifetime of trouble free service.  And just remember, bigger isn’t always better in terms of lift pump choice.

pressure-relief-valve
But Tyler, I checked that and everyone knows that Dodge lift pumps are sub-par at best.  Stay with me here, we are graduating to the high pressure side of the fuel system now.  One of the most common problems I see on common rail Cummins, is the pressure relief valve, or PRV for short.  For those unsure of exactly what I am talking about, this is the large fitting on top of the fuel rail that has a fuel line attached to the top of it via a banjo bolt that then returns fuel back to the factory fuel filter.  The pressure relief valve is designed to do just as the name implies, relieve pressure.  Specifically, it begins to open at 26,000-27,000 PSI and return any excess fuel to be recycled back into the system.  Commonly, these valves will get stuck in the open position and stay that way when the truck is turned off.  If the valve is stuck in the open position, the truck is unable to build the necessary fuel rail pressure (5,000-7,000 PSI) for startup.  Remember, this is a common rail system and that pressure is absolutely necessary for the fuel to be atomized properly to create combustion.  To visualize this, imagine trying to blow up a balloon with a gaping hole in the side of it, not happening, right?  In most cases, we sell either a new replacement pressure relief valve to return the system to stock, or a PRV Block Off to eliminate the relief valve all together.  Some would argue that installing a block off is unwise when combined with a factory fuel system because it cannot protect itself against pressure spikes. Now, I have been around these engines quite a bit, and have installed countless block offs in completely stock trucks without a single issue.  This fuel system is designed to handle exceptionally high pressure, so a small spike in pressure for .00001 of a second should not cause any damage. The benefit of installing a block off as opposed to a new PRV?  Well, that’s simple; number one you’ll never have to worry about a blown PRV again, and secondly, a block off is substantially less money.  With that said, I Pressure Limiting Valvedon’t recommend running a stock fuel system with a rail pressure box, such as the TS-MP8 on its max setting, combined with a block off, as it will over stress the fuel system.  Which one is right for you?  That’s up to you and your truck, but as always, if you need guidance, feel free to contact us and we will help steer you in the right direction.

Before we go to another portion of the fuel system, another quick check is the transfer or connector tubes. This is the part that transfers fuel from the high pressure common rail to the injectors. The fuel line from the rail connects to the inlet and is seated against the injector via a jam nut. There was actually a TSB (Technical Service Bulletin) from Dodge years ago regarding the tubes losing torque, causing them to leak between the injector and the tube. This can easily be checked by removing each individual fuel line and checking the jam nut to ensure it has the proper torque. I torque tubes to around 55 ft. lbs., factory spec is 35 ft. lbs.

Now you may say, “guess what Tyler, I’ve already checked that, what’s next on the docket?”  Well fellow Cummins connoisseur, I have your back yet again.  This next test gets a little more involved.  Each of the six injectors in your engine will return fuel.  The maximum amount of leakage on a warm engine is 160 mL per minute at about 1200 RPM’s.  During cranking, you want to see 90mL, or about the amount of fuel that would fit in a double shot glass, essentially not a lot of fuel.  In order to perform this test, you will need that trusty bucket yet again to capture the return fuel, as well as a small section of hose that will be used to extend the return line somewhere where you can watch and hold the bucket.  If you look in the driver’s side front fender well, there are two hard plastic fuel lines with a clip attaching them about halfway up the engine. One is a return from the CP3 injection pump coming out of the fuel filter canister, and the other is for the injectors coming from the back of the head. Make sure you are only dealing with the line coming from the back of the head. You will take that line and detach it by releasing the clip.  Now that the return line is free, attach your hose to extend into your trusty bucket.  Finally, have a helper hop in the truck and start cranking.  Unfortunately, this particular test requires you to crank the engine for an entire minute, which will seem like an eternity to you, your starter, and your batteries.  Being the spec is only 90mL, if you have gone past that in the first 15 seconds, just stop, as we know there is a problem at that point.  Usually a good working set of injectors that are returning the proper amount of fuel will just lightly trickle out of the return line.  Any result over 90mL means the injectors are returning excessive fuel, and they either need to be repaired or replaced.  This is also a great test if you have lost fuel economy, but the truck seems to be running properly.  A slight drop in injection pressure caused by excessive return will cause improper atomization, therefore decreasing efficiency. That’s another topic I’m sure I could elaborate on for a few pages about, but that’s for another day!

fuel-control-actuator
If you have checked everything and we still have a no start condition, I would look at the CP3 injection pump. The only way to really test the output of the CP3 is to send it to a fuel shop and get it on a test stand. There is one test you can do at home, but it is definitely a backyard mechanic test, and not a true determinant for the health of the pump. We will be looking at the Fuel Control Actuator, also known as the FCA, M PROM, and I have even had people call it a pressure regulator.  This is the two wire actuator coming off the back of the CP3, and is the only electronic connection on the pump. This sensor basically tells the CP3 what pressure it needs to be at.  In some instances, this actuator will either get stuck in a certain position or stop operating altogether. When this sensor is unplugged, the pump loses its ability to restrict flow, thus will run at maximum pressure, which is exactly how we will run this test!  We are going to unplug the FCA and attempt to start the truck.  Keep in mind you Cummins techs out there that say this is not a valid test, as this test is not for you.  This test is for the hard working Average Joe that doesn’t want to take his truck to you and pay your $120 per hour labor rate.  Alright, now back to the test, if the sensor is unplugged and the truck starts, we can assume the sensor is not functioning FCAproperly, which again, is a very commonly failed component.  Now very important, if the truck starts, make sure you quickly turn it off, as with the FCA unplugged, there is no metering of the CP3, which means it will run at maximum capacity, causing elevated RPM’s and a rough idle.

All of the above tests are intended for the do-it-yourselfer, and will typically lead to the underlying cause of the issue in most instances we have encountered.  However, if after performing these tests the diagnosis is still uncertain, the problem is probably more in-depth.  As always, if you have any questions about the above information or any of the products mentioned, do not hesitate to give us a call or send an e-mail to [email protected] and we would be happy to assist.

Tyler Lucas
Assistant Sales Manager

[email protected]

(888) 99-DIESEL Ext. 103

None found.

59 thoughts on “2003-2007 Cummins No Start? No Problem!

  • January 4, 2017 at 4:35 pm
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    What do I do when I still have no fuel out the high side of the CP3 Ive taken the line off and there is no fuel while cranking. I am getting slight pressure out the return fitting when I crack it open. With the lift pump running.

    Any advice would be great.
    Thanks Sam

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    • January 5, 2017 at 8:17 am
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      With all the lines connected, if you unplug the FCA, will the truck fire? Unplugging the FCA should make that pump go to max pressure. You may have an issue with the pump itself.

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    • September 15, 2017 at 5:49 pm
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      Sam, I am having the exact same problem and was wondering if you ever got it figured out. Any info would be good.

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  • January 31, 2017 at 4:55 am
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    Nice write up Diesel Josh. The one thing that I would add as I have been faced with this is when you have a condition where the cranking RPM falls below the threshold of what I believe to be 150 RPM, (measured with a scanner) assuming CP3 Pump works fine and injectors do not leak over the threshold (either via the connector tubes which is measurable via the return or the injector tips). If one is not able to start the truck due to lower than 150 RPM which I believe to be the minimum cranking RPM, however when plugged in the engine is easier to turn and the RPM goes over 150 and the engine starts then one can rule out the fuel delivery, including injectors, CP3, lift pump etc. This is where one wants to suspect the electrical delivery such as the week batteries or starter and wires. It does not meant that fuel delivery is optimal as the additional cranking speed may be required to bump up the rail pressure to the minimum requirement however this would only be seen in borderline situations. All I know is if a truck starter can’t produce 150 RPM then that’s the first thing to fix before looking at fuel delivery.
    Thank you for taking the time to do such a great write up.

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    • January 31, 2017 at 7:50 am
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      Thanks so much for the response on the write up. And yes, you are exactly correct that you at least need to have adequate charging and cranking speed in order to initially fire the engine. Great response and additional information, thanks again.

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  • March 23, 2017 at 6:56 pm
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    Hi, thanks for the very informative article.????
    But just to be sure, if my truck starts fine after being plugged in for three or four hours than that rules out fuel delivery as a possible cause?
    I’ve replaced one of my grid heater solonoids and checked the other one and it works. I’ve also cleaned all of my connections and the grid heater seems to test fine and heats up to some extent (not sure how hot it’s supposed to get) but my truck is still hard to start at temps under 70f unless I plug it in.
    Any suggestions would be appreciated. ????

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  • April 13, 2017 at 7:24 pm
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    So I cap the #3 injector at the rail and it will start. I reconnect the injector line and it will start. If I do not cap it off and leave the injector line alone it will not start no matter how long you crank. I put on new injector line. Same issue. Makes no sense to me..

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  • April 14, 2017 at 12:27 pm
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    Well if you cap # 3 and it starts, and when fuel is allowed to flow to that #3 Injector it doesn’t, its more than likely returning to much fuel to where it is dropping rail pressure enough to not fire the engine. I would move #3 injector to another hole and see if the problem moves to that hole. If it does then you know you have a bad injector.

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  • June 6, 2017 at 10:30 am
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    nice write up, have done everything in your article still no start, have a 09 6.7 with low km truck just quit on the hwy. new lift pump new injector pump new crank sensor. will crank all day lots of amps. no codes on the dash ( engine light will flash, have a lift pump gauge not working no other codes) I have a delete kit that was installed yrs ago no issues. After trying everything no luck now I know what your going to say but I tried a sm squirt of either engine fired right up but would only run when throttle was 1/2 or greater will stall when i let it try to idle. Is there a sensor somewhere that controls the fuel on start up? Any help would be appreciated .

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  • June 19, 2017 at 9:45 am
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    I have a 2007 dodge Cummins 6.7 6speed..terminals went bad but would still push start easily..changing out terminals a wrench arched the grid heaters solenoid and has not fired up sense..any ideas would be greatly appreciateed

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  • June 23, 2017 at 1:02 pm
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    the truck will run until it gets a half tank of fuel . the truck will start back up but want go far before shutting down again. put fuel in truck will run ,until half tank again and runs good

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    • September 21, 2017 at 12:56 pm
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      had the same exact issues, my lift pump in the tank was restricted with debriss, changed pump, runs great.

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  • June 23, 2017 at 1:03 pm
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    have changed pump in tank and on the fuel filter housing

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  • August 18, 2017 at 1:59 am
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    My 04 will only start on either or roll start. New crank sensor. I checked for fuel getting to the fuel filter and I can hear the pump. Does the grid heater have to heat up for the cummins to start?

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    • August 18, 2017 at 7:09 am
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      Negative. Only in cold climates will it make it noticeable easier to start with the grid heater, but it will typically not prevent it from starting unless its VERY cold, which is not typical for this time of year, of course. Further, I’m not following, are you saying that it only starts on a roll start, as in bump starting like you’ve got a manual transmission, get the truck rolling and pop the clutch?

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  • September 13, 2017 at 9:56 pm
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    Great article a lot helpful information. Found that the truck I was working on had four loose injector nuts. Tighten them all and the truck starts and runs great.
    Thanks for the help I will definitely be going to diesel power products for any future parts or advice. Thanks

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  • September 15, 2017 at 3:56 am
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    My 04 has an intermittent stalling problem. I can drive it for a few hours and it’ll run great then will sometimes stall. Engine will crank but won’t start. If i let it sit a few minutes it will start but then die. This will happen 3 – 4 times then will stay running and could be fine for hours. I replaced the lift pump thinking it was the culprit. I do not hear the lift pump run when the no start condition occurs. My question is what controls the lift pump and supplies power?

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    • September 15, 2017 at 8:14 am
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      It definitely sounds as though its a fuel pump related issue. Your ECM controls the lift pump operation depending on key position, which goes through a fuel pump relay. Presuming the lift pump is good, since you just replaced it (again, making a presumption) look through all of your wiring and fuel pump relay to ensure there is no break or corrosion. Beyond that, I would recommend checking the power to the pump when you have these issues. If there is power going to the pump when it will not start, its of course a bad pump again. If there is not power, you’ll need to work your way back to see where its losing power. In some cases, it can be a faulty ECM not triggering / turning on the power to the pump. Further, as a side note, 2004 models originally had the lift pump located in the engine bay. Later, it was determined this was a bad location, causing them to be susceptible to failure. Dodge released a retrofit kit that would move the pump into the fuel tank’s pickup basket assembly. Not sure where yours is located.

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      • September 17, 2017 at 5:06 am
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        Where is the fuel pump relay located on an 04 5.9? I only see a fuel heater relay in the distribution box.

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        • September 18, 2017 at 8:28 am
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          You are correct, I misspoke. After some research again, I was thinking of when the in-tank conversion is done, then a relay is added. From what I can recall and after confirming with some quick research, there is no relay for the stock filter mounted lift pump. When the in-tank conversion is done, an in-line relay is added, but in your case, its completely controlled by the ECM. In the instances when your truck will not start, confirm if you can hear the lift pump cycling by turning the key to the on position and listening in the engine bay. If nothing, then its confirmed you’re either not getting power to the pump or the pump is bad. The stock pumps are known to work intermittently when they are failing, so unfortunately it may be that its going out again. I would recommend giving us a call and we can help steer you in a direction to get the truck back up and running reliably again. 888-99-DIESEL.

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          • September 18, 2017 at 4:43 pm
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            I will definitely call. Now I can get it to act up. I can drive it for about 2-3 miles then shut it off. Let it sit for about 5-10 minutes then it will continuously start and die. If it sits for about 15 minutes i can usually get it to start and drive. I’ll call soon. Thanks for the help!!!

          • September 18, 2017 at 5:00 pm
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            That does sound like the lift pump is overheating and not allowing it to start if you try and start it when the pump is still “hot.” I had to read your symptoms several times, as it almost sounded like a different issue. In instances when it will start back up again immediately, but not as likely the longer it sits, that, in many cases, is actually the pressure relief valve on the fuel rail that is failing. But again, you are the opposite situation. We look forward to hearing from you.

  • September 15, 2017 at 5:55 pm
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    My lift pump is located on the side of the filter housing. Thanks for the input and I will post my findings! I wish it would quit for good so I could track it down.
    So does the fuel pump retrofit eliminate the hoising mounted lift pump?

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    • September 18, 2017 at 8:24 am
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      Yes, the dealer retrofit kit will eliminate the filter housing mounted lift pump with a new unit that mounts into the fuel tank’s “basket” assembly. This will include a new wiring harness, as well. While this is a good upgrade over the stock filter canister mounted unit, I would recommend upgrading to a FASS or AirDog unit for better reliability and filtration over the stock units. Otherwise, you could always go with FASS’ DRP that is merely a substantially better lift pump than stock, but keeps it in the engine bay. This is better than the retrofit kit, but not as good as a traditional FASS that mounts to the frame rail. Overall, its a good way to get a much better pump with an easier installation and less expensive than a frame mounted unit.

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  • September 23, 2017 at 9:33 pm
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    Tighten the jam nuts at the end of the injector lines may have solved my issue. I have a very short crank time now(comparatively) after completing this. Thank you!

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  • September 27, 2017 at 12:24 pm
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    Hi. Found your write up to be very helpful but am still needing expert advice.
    Here goes. Filled up the truck with diesel 5.9, drove 20 miles and truck died conveniently in front of son in laws work. Got out of truck to notice fuel spilling all over the road. Son popped hood and said it looks like it’s coming from fuel rail. Replaced the lines but now it won’t start. Cranks but won’t turn over. Lift pump works, got fuel in filter but only about 1500 ps. Neighbor put it on a computer and said it’s either cp3 or fuel injectors. Now before I start spending big dollars on injectors and or pump is there a way to test the pressure relief valve short of ordering a replacement?
    Tia

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    • September 27, 2017 at 1:55 pm
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      Hi there, thank you for reaching out. With the truck not running, remove the fuel line on the top of the pressure relief valve and physically move it out of the way. That line routes relieved fuel from the valve back to the fuel filter canister. Fuel will take the path of least resistance and without physically moving the line off of the top of the valve, fuel coming out of the line will make it look as if it is coming out of the valve. Once the line is removed, crank the truck. There should be no fuel coming out of the top of the valve during cranking. If there is fuel coming out of the valve, it is bad and needs to be replaced. I would do the injector return test that is outlined in the 3rd to the last paragraph in that write up. If you have any other questions, feel free to give us a call at 888-99-DIESEL, as well.

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      • September 27, 2017 at 5:19 pm
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        Awesome, thanks for getting back

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      • September 30, 2017 at 1:45 pm
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        So, checked pressure valve. No problem there. Did the injector test and had lots of fuel with in a second. So that tells me it’s an injector. My question now is, suppose it’s only one injector gone bad can I get away with purchasing just one or do you recommend the whole set?

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        • October 2, 2017 at 8:18 am
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          We get this question a lot. Yes, if you only have one injector that is returning higher than normal, you can definitely replace only that one injector. BUT, in our experience, when doing this, its typically not long before other / all other injectors begin to fail, meaning you’re in there again replacing more injectors. Obviously, its best to replace all of the injectors at once, and if the truck has in excess of 150,000 miles with the original injectors, the rest are probably on their way out, as well.

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  • October 14, 2017 at 5:17 pm
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    2005, stock, 5.9, 100,085 miles, auto. 90 degrees, humid and sunny. After a 70 mile interstate trip and 4 hours shutdown, with less than 1/2 tank of fuel remaining (fuel at least a month + old) at the first stop sign 1 mile away on the return trip, truck hesitated upon applying throttle to proceed but moved on without issue. Ran fine to next stop sign 2-3 miles away. Next 5 stop signs, 2 miles apart, engine stopped in mid-intersection of each upon throttle application. 15 seconds of cranking each time, restarted, idled smoothly, and ran to next intersection where it died again. On to highway speed at 55 mph, 3 miles and truck died completely. Coasted into parking lot, and gave up trying to proceed further for night. Returned with a used FCA temporarily removed from a twin good running truck of same vintage as above. Started after long cranking, stalled a couple of times but began running smoothly. Tried to proceed, but 8 miles up the highway, truck died again while at speed as if out of fuel. Towed to a diesel shop, and waiting diagnosis next week. Ideas from here for now?

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    • October 14, 2017 at 5:20 pm
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      EDIT by Dougie: Truck threw a P 0088 code. High fuel rail pressure.

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    • October 16, 2017 at 3:22 pm
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      Thanks for reaching out to us and sorry to hear about the issues with your truck. In regards to the P0088 code you’re getting for higher than desired rail pressure, you were correct in replacing the FCA as that is many times the cause, however, since it did not alleviate your issue, the next step would be to check the rail pressure sensor. Otherwise, we’ve seen that code thrown when its not necessarily the excessive rail pressure causing the issue, just the fact that the truck had higher than desired rail pressure during the “issue” because your RPM’s were lower because of the misfire resulting from the rough running condition, as an example. So again, its not that the high rail pressure caused the problem, its that the rail pressure was higher while the engine was running rough and even dying, than under normal circumstances. Its almost sounding like a fuel quality issue or even lift pump related. I’m sure the shop’s first order of business will be to check your fuel filter which will tell the tale of fuel quality after initial inspection. From there, presuming they will check the health of the lift pump and move on from there. Good luck in getting the truck back up and running.

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  • October 21, 2017 at 3:39 pm
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    I have performed all these test but truck would not start without starting fluid. It would not start without the fca unplugged but once it started I unplugged it and idle did get rough. Is that normal? I have replaced both pumps. Once running it has all power it needs and get a speeding ticket if not careful. Any help would be nice.

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    • October 23, 2017 at 9:49 am
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      Yes, it is definitely normal for the truck to run rough once you unplug the FCA as the rail pressure will run higher than desired at the lower RPM’s at idle. If you haven’t already, another thing to check would be the rail pressure sensor as its sounding like possibly the ECM is not properly registering the amount of rail pressure until the truck is running. The simplest method would be to swap the sensor from another truck if possible.

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  • October 23, 2017 at 4:21 pm
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    Ok thanks. I did notice today when I tried to start after sitting for 24 hours the rpms only got to 100 and once ether kicked in it fired when it reached 200. It seems I may have 2-3 issues that may be going on. I will post what I find out. It may take a few days but I will post an update. Thanks again.

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  • October 25, 2017 at 8:35 pm
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    Have 2006 5.9 that is very hard starting when warm,starts fine when cold . Have changed both pumps ,and filter . My question is which sensor should I start with ? It was checked for codes at the dealer and nothing came up ..Help please ..

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    • October 26, 2017 at 2:52 pm
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      Hi there, and thanks for the question. The first thing we would recommend checking is your pressure relief valve located on top of the fuel rail, which there is a tutorial on how to do in this blog post. If the PRV checks out fine, then the next step would be to test the fuel return rate of the injectors. Good luck, and let us know if you’ve got any other questions.

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  • November 6, 2017 at 10:36 pm
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    I have an 07 5.9 that developed a long crank problem. it started cranking for 2 times as long as normal a few weeks back. Since then it has gotten long up to 15 seconds and sometimes an initial of 15 followed by 10. It is assumed that it’s taking this time to build up rail pressure. Once it starts it runs like a champ and has no issues running, pulling for hours or hundreds of miles, unless i kill it. This issue doesn’t change if it’s cold or hot, warmed up for first start in 3 days. As soon as the key is turned off and you quickly try to re crank it or let it sit for days its the same. I have put a plug in the place of the rail pressure relief valve and just finished ordering a rail pressure sensor. What are your thoughts on this one? Thanks in advance.

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    • November 7, 2017 at 10:14 am
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      This sounds exactly like injectors that are returning too much fuel. I would check the fuel injector return rates while the truck is cranking. This can be done by removing the return line at the rear of the head and plumbing it into a bucket that can collect the return flow. During cranking, there should be a very minimal amount of fuel coming out of the line, as in drops of fuel, and definitely should not be a steady stream. If it is a steady stream or anything other than drips, we have injectors returning too much fuel and it is just taking excessive cranking to overcome the return and build up enough rail pressure to start the truck. Presuming so, the trucks fuel mileage is probably down, as well. Hope this help alleviate your issue. If in fact you are experiencing excessive return, the fix would be to replace the injectors and injector connector tubes. We have numerous options available and if you have any other questions, please do not hesitate to give us a call at (888) 99-DIESEL, send an e-mail to [email protected], or reply to this message, as well.

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  • November 28, 2017 at 4:05 pm
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    I have a 2005 just installed new injectors, wouldn’t fire. Deleted the relief and fired right up. Went for a little rip and it ran ok had code MAF that was unplugged. Went over the truck and got it buttoned up, had it idling for about 15 min. Went around the block and down the street it died and won’t fire at all now.

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    • November 29, 2017 at 7:39 am
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      Did you completely clear the MAF code? You can leave the battery cables completely unhooked for about half an hour if you don’t have a scan tool to accomplish this. If you’ve done this, its possible you have a bad injector harness. Short of completely replacing, you can test it by disconnecting each wire from each injector and ohm testing the harness. You should get 0.05 ohms or less. If you have a pinched wire, it could easily be causing a hard or no start issue. Another thing to try, unplug the Fuel Control Actuator (FCA) on the CP3 injection pump and try to fire the truck. The FCA is a metering device, so if it fires up, immediately turn off the truck as it will overpressurize the system. But if it does start, chances are you need a new FCA.

      Reply
      • December 1, 2017 at 3:12 pm
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        Yes I cleared the code with my smarty. I tried unplugging the FCA and no change. I redid my injectors and injector tubes just to be sure, tried again and I got inlet air temp p0073, cp3 pump p0251, cooling fan p0480. Still no start. Thanks for the help so far.

        Reply
        • December 4, 2017 at 2:02 pm
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          Okay, first off the fan clutch code p0480. That could be a blown fuse or a bad fan clutch itself. While not something that “notoriously” fails, they can and do fail. The P0251 code, that seems associated with unplugging the FCA (fuel control actuator) and should clear and we would expect that not to return once cleared. The air inlet temp code could be related, but that is not stopping the truck from starting. I would suggest at this point, starting somewhat from the beginning and verify lift pump pressure first. Something is being missed here, you have to be losing pressure somewhere. For it to die randomly, the truck is either not getting fuel to the injectors or its electrical like the injector wiring harness. If you’re able to test what the fuel return volume of the injectors are for 10 seconds of cranking and what is the actual lift pump pressure, that would help in diagnosing the issue. Also what is the resistance reading on each injector solenoid and harness.

          Reply
          • December 4, 2017 at 4:26 pm
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            Ok so the injectors test out between 0.4 and 0.7 ohms and the harness tests at 0.1 ohms with a fluke meter. I think the fan code comes from a broken pin in the connector. I did a quick fuel return test and it looked a bit more then it should so I redid the injector install and double checked the torque specs. I cleaned out and dielectric greased connectors. I have not tried to fire since I did this. I have a 150 fass with new filters and the cp3 has a bag of parts kit. I don’t have an actual pressure reading yet but I am working on that. I will do a better return test and get back to you.
            Once again thank you very much.

          • December 5, 2017 at 2:40 pm
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            So it sounds as though the harness is good. Let us know once you get a new return test done as the preliminary test sounds as though it may be causing excessive return. But even at that, it would have to be very excessive to cause a no start issue. Possibly, you had an issue with how the connector tubes were seating into the injectors, as this is a common issue, and hopefully your re-installation cures this issue, if it was the culprit. Long story short, most people install the injector completely, then screw the connector tube in, when in fact, you need to slightly tighten the injector, then the tube, then the injector a little more, etc. so the tube can properly seat into the dimple on the side of the injector. Otherwise, fuel will bypass the injector, or even partially block it. Good luck!

          • December 6, 2017 at 2:47 pm
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            Ok so just did a return test and I’m only getting about 10 – 15ml of fuel. I hand tightened the injectors and backed them off and installed the tubes and torqued to 50 ft lbs I know that more then suggested but I want to make sure they are seated. Could my cp3 be acting up? This is my hot street project and everything but injectors sat on my bench for over a year.

          • December 7, 2017 at 8:45 am
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            The return sounds good and your reinstall with the injectors and tubes is spot on. Honestly, they can use more torque than the recommended to really seat them well. Yes, starting to lean towards CP3. Did you just install the bag of parts, or had it been on the truck for a while? Have you tried swapping out the FCA with the stock one? Also, when you change out the fittings on the CP3 with the BOP, did you absolutely make sure that the little tiny ball was reinstalled? Its easy to miss.

          • December 9, 2017 at 8:59 am
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            I did the bag of parts a couple years ago. Was one of my first mods. I actually did drop the check ball in the driveway and had to order a new one. I just swapped the stock FCA in and no change at all. I’m honestly at a loss. I just need to move the dang thing so the fiancé can park in the garage now that the snow is flying. I defiantly need to get a rail pressure gauge. Any real way to see if the cp3 is done?

  • November 28, 2017 at 4:28 pm
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    I have a 2006 2500 and it wont even crank over it just clicks so i pulled the starter put a new one in and it still just clicks i used a test light cheched the wire comming from the ignition and thats good the clicking is comming from a relay by the drivers side battery where do i go from here?

    Reply
    • November 29, 2017 at 7:41 am
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      From the information you’ve given, this honestly sounds like you simply don’t have enough battery voltage at cranking. Your ECM requires a minimum of nine volts to do absolutely anything. What we would recommend doing first is to check the battery as you’re attempting to crank over the engine, so have one person holding a voltmeter on the battery post watching the voltage drop and another turning the key. Even though you may be showing 11+ volts at static level, you could very easily be dropping below nine when trying to crank, which would cause the relay to merely click.

      Reply
  • December 13, 2017 at 1:30 pm
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    I have an 07 Dodge 2500 with the 6.7 cummins and as above I am unable to start it after getting water in the fuel. So far I’ve dropped the tank, cleaned it and installed a new pump and installed a new filter. It was still showing low fuel rail pressure and gave me the error that the rail pressure relief had gone off so changed that and still wouldn’t start so changed the injector pump and had the injectors cleaned. It still won’t start but will try with a shot of either can jou give me any suggestions as to what else it could be?

    Reply
    • December 14, 2017 at 7:28 am
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      I would be looking at injector return flow. Just simply cleaning injectors will not fix them. Water contamination creates cavitation under the high pressure that the fuel system is under. It will do just as much damage as sediment would. I would test the injector return rate for sure. The maximum allowable return while cranking is 90 ml per minute. So not much that’s only just over 3 ounces.

      Reply
  • January 10, 2018 at 1:14 pm
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    Great write up and thanks for giving out the information. It seems everywhere else you look for some help, someone wants to make money for helping others. I’m about to start the tests. Before I do, the not start problem I’m having is when we drive our 2007 dodge ram and park it and try to re-start it again in about 2-5 minutes later. Just cranks. I’ve noticed if you wait longer it takes a bit longer to crank and finally fires. If you at least wait somewhere after about 15-25 minutes later it starts fine. So if you take it out for a long trip and get back in it to start right away not a chance. let it sit for a while and it starts. We already have a new pump in the tank from the summer. If it were the pressure relief valve? Wouldn’t the pressure sensor set an engine code and light up telling not enough rail pressure? If so I’m going to the next step. if not then start with the valve and next in order. Thanks.

    Reply
    • January 12, 2018 at 8:49 am
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      The pressure relief valve is a great place to start since you have already addressed the lift pump. When it is in its no start condition I would remove the Banjo bolt on the top of the relief valve and push the line out of the way. See if it is relieving fuel when you are cranking the truck. If it is perking fuel when cranking, the relief valve is bad. Sometimes they will throw a code and sometimes they won’t. I see this issue a lot with trucks that have high return rates on the injectors, so the injector return flow test would be the next test if the relief valve checks out good. Good luck and let us know if you have any other questions.

      Reply
  • January 22, 2018 at 2:43 pm
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    If I have to much return fuel from back of head should I try injector tubes first or am I wasting my time and just putting off the inevitable.

    Reply
    • January 22, 2018 at 2:52 pm
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      Unfortunately, its not common to have the connector tubes be the culprit for a high return rate unless you’ve had them out for any reason and they aren’t properly seated into the injector. In that particular case, unless they were just loose, you would have an issue where the tip of the tube has a seating ring around it from where it should be seating into the injector body, but not properly seating. But again, that only happens typically after you’ve had the injectors and tubes out. Further, its POSSIBLE for it to be the Fuel Control Actuator (FCA) of the CP3 injection pump, but in most cases, these don’t supply enough pressure, but your symptom would be caused by too much pressure. So yeah, you’re most likely needing new injectors. Let us know if you have any other questions.

      Reply

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