03-04 Injector testing or diagnostic

[Mdracing57]

Anyway to diagnose a possible injector problem on the 03 and early 04 models ? Balance rates are not supported and didn't see anything like cylinder contribution test or injector kill test. I have custom tuning done but trying to track down a problem myself, it does it on stock tune as well. Truck has some smoke at idle and poor fuel mileage. It also has a pop that has been chalked up to a 03-04 thing but I believe mine is more than that, just does it too often and on any of the tunes. I did a simple test on the exhaust manifold with a temp gun at idle and one is reading about 30 degrees colder than the rest and the rest are all consistent with each other, has me thinking a leaky injector. It's a completely new build with about 10'000 miles but I think I might have a bad part.

Thanks

[Derekb707]

I am kind of in the same type of situation. Have a custom tune that is locked down where I can't see anything. Truck idles fine, runs good with the exception heavy acceleration most noticed in 2nd and 3rd gear (03 nv5600) where I will get a sputter when I stomp on the pedal. Rail pressure meets demand, but acts like it is hitting a rev limiter or something of the sort.

The guy that made the tune files says the 03/04 have problems with fast rpm changes where the ecm can't read as fast as the later truck, but it leave me wondering if it is tuning or a mechanical problem. I have new injectors, but I am wondering if they are all functioning perfectly.

[Monzsta]

Check and verify your valve lash before anything. If you have valves being held open when hot it'll cause a rough running condition. Also retorque your crossover tube nuts to 37 ft lbs.

[30 RUM]

I am kind of in the same type of situation. Have a custom tune that is locked down where I can't see anything. Truck idles fine, runs good with the exception heavy acceleration most noticed in 2nd and 3rd gear (03 nv5600) where I will get a sputter when I stomp on the pedal. Rail pressure meets demand, but acts like it is hitting a rev limiter or something of the sort.

The guy that made the tune files says the 03/04 have problems with fast rpm changes where the ecm can't read as fast as the later truck, but it leave me wondering if it is tuning or a mechanical problem. I have new injectors, but I am wondering if they are all functioning perfectly.

Derekb707, that is not a truck problem it's a tune problem. I know from experience, let me guess it does it when the tires start spinning then you get a real hard engine miss, then it comes back to life???

[Turbo_Mike]

Also check your crank reluctor wheel. If it's rusty/dirty you could be getting a bad crank position signal, which the 03/04 trucks are also bad at noticing. The 03/04 "pop" should only occurr during a very fast rpm change like an in between gear or traction loss free rev. It shouldn't happen under normal load. If you have an injector sticking open you will also notice a long crank condition during starting.

[Dom_c13b]

with a proper tune it should never happen. It's in the pilot timing

[Turbo_Mike]

with a proper tune it should never happen. It's in the pilot timing

My early 04 truck still does it with pilot injection turned off. There is most certainly a limit of rpm delta per time that can be hit.

[Moparmatty]

I am kind of in the same type of situation. Have a custom tune that is locked down where I can't see anything. Truck idles fine, runs good with the exception heavy acceleration most noticed in 2nd and 3rd gear (03 nv5600) where I will get a sputter when I stomp on the pedal. Rail pressure meets demand, but acts like it is hitting a rev limiter or something of the sort.

The guy that made the tune files says the 03/04 have problems with fast rpm changes where the ecm can't read as fast as the later truck, but it leave me wondering if it is tuning or a mechanical problem. I have new injectors, but I am wondering if they are all functioning perfectly.

Derekb707, that is not a truck problem it's a tune problem. I know from experience, let me guess it does it when the tires start spinning then you get a real hard engine miss, then it comes back to life???

My early 04 truck still does it with pilot injection turned off. There is most certainly a limit of rpm delta per time that can be hit.

All tune issues. 2003 and 2004 trucks run perfectly fine just like the 2004.5+ trucks do when tuned properly.

[Derekb707]

Derekb707, that is not a truck problem it's a tune problem. I know from experience, let me guess it does it when the tires start spinning then you get a real hard engine miss, then it comes back to life???

Also check your crank reluctor wheel. If it's rusty/dirty you could be getting a bad crank position signal, which the 03/04 trucks are also bad at noticing. The 03/04 "pop" should only occurr during a very fast rpm change like an in between gear or traction loss free rev. It shouldn't happen under normal load. If you have an injector sticking open you will also notice a long crank condition during starting.

All tune issues. 2003 and 2004 trucks run perfectly fine just like the 2004.5+ trucks do when tuned properly.

I appreciate hearing this and you guys taking the time to post up. I am going to data log today and email the files in for hopefully an adjustment. @ 30 RUM, I notice it real bad at 2800-3000 rpms where power is coming on heavily, it sputters, cuts in and out, then gets over it and starts accelerating again up till redline. I'll check the reluctor wheel as mentioned and clean if I see anything. Thanks guys.

[Derekb707]

010717a.hpl

Here is a short log of what I am seeing with my truck.

[B00STJUNKY]

010717a.hpl

Here is a short log of what I am seeing with my truck.

I somewhat suspect that the fueling limiters related to RPM are at work here. You probably only notice it in low gears since it's much quicker at accelerating to a higher RPM (approaching the RPM limit more quickly) and causing the P.I.D. limiters for RPM to kick in sharply. Once you're in a higher gear, the delta of RPM rise over time is slower, so the P.I.D. is toned down, and it will feel like a more gradual defuel as it approaches the RPM limit, rather than a hard cut.

[Derekb707]

I somewhat suspect that the fueling limiters related to RPM are at work here. You probably only notice it in low gears since it's much quicker at accelerating to a higher RPM (approaching the RPM limit more quickly) and causing the P.I.D. limiters for RPM to kick in sharply. Once you're in a higher gear, the delta of RPM rise over time is slower, so the P.I.D. is toned down, and it will feel like a more gradual defuel as it approaches the RPM limit, rather than a hard cut.

That would make sense, I haven't been able to get it to happen in 4th gear and haven't tried it in 5th or 6th. I am hoping to hear back from the tuner next week, I sent him more log files today. I'll report back here if we make any progress.

I totally hi-jacked this thread, sorry to the original poster.

[Mdracing57]

I'm going to log mine with what pid's the tuner sent me when I get a chance. I'm also going to go back over the valve lash, did it at 1000 miles but have around 10'000 on it now. It has a 188/220 cam and revs to 4200. Doesn't do it on the top end though or when the converter is locked up. Only when you lets say you go to half throttle it from a roll and want to light the tires up, it will pop like crazy on anything above tow tune and then finally take off once the transmission catches up. I thought about putting a switch in to lock the converter sooner to see if that helps but my transmission isn't fully built yet.

[Mdracing57]

Oh yeah I don't think the injectors are the issue, runs fine the rest of the time. I'd definitely like to track down exactly what it is and how to eliminate it without loosing power.

[boostbuick]

Well im not a tuner on desel trucks but have u replaced the throttle body on that same years for the chevys they have alot of problems with the drive by wire shit i hate. Just trowning it out there i dont really know, unless on desel engines there isnt a throttle body and its all fuel managment with the turbo setup , sorry if i sound dumb just trying to help

[Turbo_Mike]

Well im not a tuner on desel trucks but have u replaced the throttle body on that same years for the chevys they have alot of problems with the drive by wire shit i hate. Just trowning it out there i dont really know, unless on desel engines there isnt a throttle body and its all fuel managment with the turbo setup , sorry if i sound dumb just trying to help

LOL its all good. And no, there isnt a throttle body on the cummins 5.9

There is a TPS, and its very good at throwing codes and telling you when its messed up.

[Bodie]

I have had the same problem, I believe it stopped when I raised the lower RPM timing a degree or so in the 120mm+ area. I would do it during a rolling low speed (20-30mph) burnout or traction loss. I could see it being a bunch of different things though, just so happened the timing change led one thing to another that stopped the popping.