new injectors- still running rough when cold...

josh03

josh03

don't ask
Joined
Sep 25, 2009
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Ok this one has me stumped, please someone chime in. Was sure my injectors were going south, so I took them out and sent them to industrial and they said sure enough- two of them were on their way out. Just got them back and it is running the same as before. They said that they went through them all and put all new nozzles and bodies.
When first started at idle it runs rough and smokes a lot, and when put in gear with the tight converter its gets really bad (classic bad injector, right?) But when it is absolutely warm it runs almost completely normal, makes good power, and no smoke (except maybe a tiny sputter when first accelerating from a stop).
Is there any chance that there could be something else wrong? I.E. cp3, lift pump, etc. Rail pressure seems normal (20k+). I'm running the smarty sr on level 5 with these Industrial 30 lpm injectors. This is the second time I've sent them back and its ran the same each time.
 
D A M M I T!!!!!!!!!!!!!!!
i hope someone helps you figure this out josh..
 
You need to check the holes (Compression) test,Leak down.
 
if you want you can get it down to lcd or tpd and i can see what i can do to diag it...

jason
 
Oftentimes when the injectors are going out, they operate poor enough that a piston fails. Once the timing of the injection event goes south....its anyones guess as to the damage it can cause. I get injectors in often with aluminum on the tips. Sometimes the owner does not even know he has a problem until we call and let them know the bad news.
 
thats definitely got me concerned... but at the same time, the signs are still just pointing to injectors being bad. And when I sent the injectors back this time they said that sure enough two of them were bad, so there was definitely an injector problem, so to have the same symptoms as before just leads me to believe that the problem wasn't fixed. I guess the ideal thing to do would be to pull injectors, inspect all parts, scope cylinders, and put some new stock injectors in and see what happens.

Thanks Jason, I'll do what I can, but I have a feeling I might need some of your expertise with this one. I just want to get the dang thing running right... I've been paying payments on it for nearly a year now and have driven it for less than a month lol. Just one thing after another, plain bad luck.
 
Try to isolate which cylinder is causing the problem. Multiple ways to do this. Use a block off test plug on the injector line (Cummins sells them for pretty cheap), or electrically disconnect the injector (doesn't always totally work if the injector is leaking), or measure the heat at the exhaust manifold, or use a DRB to do an injector balance test. These are just some of the ways. Once you find a bad cylinder, and a good one, then swap the injectors, and see if the miss follows the injector or stays with the cylinder. If it follows the injector then you know it's the injector. If not....

Hope this helps..
Paul
 
thanks paul, that sounds like a good idea. Out of curiosity, what are some normal temps to be seen on the exhaust manifold with good injectors, and how big of a change do you see with a bad one? Thanks
 
i am having the EXACT same problem with my truck, and just got my injectors back from II too. Still running rough at idle and when warm , its normal. Ive been leaning towards compression too, but just wont admit it to myself..
 
man, I really wish I just had some stock injectors that i knew worked that i could throw in there just to be sure. Hopefully i can get this figured out soon.
 
is the truck still hazing? if so then a test that works better then temps is to remove the exhaust manifold and start the engine. see which hole/s the smoke is coming out of. temps can be misdiagnosed the longer the truck runs...
 
good idea jason... when i get a moment ill pull the ex. manifold off and see which cylinders the smoke is coming out of and then change injectors around and see if the smoke follows certain injectors. I'll let you know my results
 
ISBeINSIDE said:
is the truck still hazing? if so then a test that works better then temps is to remove the exhaust manifold and start the engine. see which hole/s the smoke is coming out of. temps can be misdiagnosed the longer the truck runs...
Click to expand...

hahaha interesting idea.
 
do it all the time, usually the the cummins's 855 l10 m11's and such...

jason
 
Well it was a good idea Jason, I did it this morning--- pulled the exh. manifold off, started it, smoke was pouring out of the #1 cylinder... took the #2 injector and swapped it for the #1 and started it and smoke was pouring out of the #2 cylinder. The smoke followed the injector so I think its safe to say that the 1 injector is bad. I must say, this pretty much ruins my faith in industrial injection... at least their injector testing procedure... these injectors were sent back two times and this is the third time I've had to install them and it looks like one has been bad everytime. I'll try to get this one sent off and hopefully have them send me a new one quick status... fingers crossed, thanks for all your help guys
 
Just talked with industrial and they have another one on the way, great customer service. Just hope that everything works when it gets here!
 
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