Engine miss at idle when cold only

[Gray 5.9]

About two months ago my truck started missing pretty bad out of nowhere and couldn't figure out what was going on. I keep a close eye on my own oil and fuel filter changes most of the time, and wouldn't figure id have major problems with the engine. Well i took the truck too a qualified diesel shop where they have the tools to diagnose the injectors and fuel system, and they found four bad injectors, two didn't have a good spray pattern and the other two had bad solenoids. The shop changed out all the injectors with all stock up to date ones, and also tested the main HP pump,rail switch etc. . and i just put a new fuel lift pump on the filter housing from Geno's. After all this was done everything tested out well "good to go". Just recent in the last few weeks when i crank the engine up when it's cold first thing in the morning going too work, it has a missing sound from the engine as in a gas engine has a bad spark plug, but it doesn't shake and at the exhaust pipe with a stronger than normal rich fuel smell This only lasts untill it gets fully warmed up, then all missing goes away with no codes (weird). It's as if somthing is expanding as the engine warms up. Have you guys or gals had this happen before. Ive read were the engine gets worse as it warms up but haven't found anything that relates to this issue. Thanks

 

[TCDiesel]

Bad soleniod?. . Hmmmmmmm thats likely as A hurricane in MN,they work or don't, the default position is de-energized,Up to date ones=ultrasonic cleaned and part harvested, O course this is just My guess.

 

[cerberusiam]

Injector hanging open when its cold is also a possibility. The rich fuel smell almost indicates excess fuel, but, a solenoid not working fast enough will delay injection and dump raw fuel into the exhaust stream. Solenoids may ohm fine closed but just not function when activated. Definitely one of those things that is HARD to nail down.

 

[Gray 5.9]

Hello Cerberusiam, I was kind of wondering if it might be an injector but wasn't shure. just wouldn't expect it from new ones. I called the mechanic that did the work and told him what it was doing, and he wants me to bring it in as soon as i can. If i continue to drive it, will i be damaging the engine.

 

[cerberusiam]

You got new injectors, does not mean the inejctors themselves were NEW. Thats the biggest problem with the injectors out there from a non Bosch specific shop, you don't know what you get. I would definitely nail down the source of these injectors.

The only way to be semi satisfied you have a good injector is a Bosch Certified Reman Injector. Good chance you will get actual NEW injectors even though the part #'s say reman. Even the Bosch Certified remans seem to be halfway decent. At least they stand behind them.

With your immediate symptoms you probably won't hurt the engine. However, if there is one going bad it could stick open any time and melt a piston. With definite symptoms like that is is a crap shoot to drive it much if at all.

 

[Gray 5.9]

I really appriciate the response Cerberusiam, Ive been a loyal owner of two cummins powered trucks, wouldnt think id have injector problems unless i were racing, or had a major fueling programmer. Ive looked at all the equipment that has the HPCR cummins such as cranes, generators, and other industrial applications, and only noticed that most all of them have at least two fuel filters, dual air filters which would be more apt to harsher conditions but thats all. I wonder about those applications, that may be much different than a pickup truck app as far as the way there fuel system, and programing are setup for reliability. Makes me want my 94 dodge cummins back with the 12 valve with the more simpler pop off injectors. Better yet install a p7100 pump, 12 head, etc. . lots of work to convert but i would know whats going on.