weird symptoms please help.

[Mindbndr]

Well to start off, I have a 2003 2500, original symptoms were rough idle and white smoke at start up, along with white puffs of smoke from crank case breather. So with the help of all of you i replaced all six injectors, and the truck ran better but still has the rough idle. The weird thing is that occasionally the truck runs really smooth and the white smoke from the breather goes away, but that lasts very briefly and then the rough idle comes back. Now when i say rough idle, i do not mean running on 3 cylinders, its pretty slight but very noticeable when it starts to smooth out. And last but not least after changing the injectors the weird symptom started. Occasionally when driving at a slower pace, like through a neighborhood, and i let off the gas the truck dies then comes right back up to its same old rough idle. So any help out there would be greatly appreciated. Only upgrades to truck are mac intake, and mbrp 4" turbo back, i used to have the superchips tuner on it but that thing sucks. please help

 

[TCDiesel]

Did you follow the installation found here 5. 9 CR Injector Installations to the letter? if Yes go back and increase your final TQ to 100 inch lbs on the injectors & 50 Ft lbs on the retaining Nut on the Tubes.

 

[Motorhead]

If you are getting blow-by, I would recommend doing a compression or cylinder leak down test.

 

[Dbonzi]

I wouldn't think blow by (or leaking compression) would be intermittent.

Would it?

 

[JJPage]

How's your lift pump? I know that would not create the blowby, but if it is starting to fail, intermittently starving your CP3, that could account for the rough idle and almost dying, so could a loose wire on the lift pump or FCA. The rail pressure sensor starting to act up will also produce such symptoms.



I am really tiring of the electronics on these trucks, if your lucky enough to have a friend with the same rig, you are able to swap parts temporarily to test, otherwise it's buy and swap, if it doesn't cure the problem, you have a spare part, but less spare cash...



Hope you find the problem, keep us current.

 

[Mindbndr]

I didn't think it would be intermitent either. Can I do a leak down test myself, or does cummins need do that.

 

[p-Bar]

Throw some 2 stroke oil in the fuel tank if symptoms go away probably your FCA

 

[Mindbndr]

Thanks all for the help. As for the lift pump question. I dot have a gauge, but Im working on it. Hopefully this weekend. I will let you all know what happens. As for the 2 stoke oil, any specific brand, and roughly how much. Something else to add about the "blow by" I don't think it is blow by because it seems to clean up the second i give it some gas. The smoke dissapears when i press the pedal. Weird I know.

 

[p-Bar]

you can put a quart in but a pint would do

 

[Bob4x4]

Seeing as how the problem started after the injector install... ... ... either injectors or much more likely the install did not go well. It would be better if you had a rail pressure gauge reading before and after the install. You could also do an injector return test

 

[Missouri Mule]

Mindbndr, 2-cycle oil needs to be ashless. Any brand you like.

 

[Cumminsduallyguy04]

did you ever fix your problem? I had the exact same issue... just on a much larger scale i pulled the head changed gasket (job includes removal of fuel system). I put back together and it would not run. i had a crank sensor code so i replaced the sensor... nothing still. i figured i installed head gasket wrong by chance so i tore it all back apart and installed another head gasket (what are they like 120 a piece). This time same thing except the truck seemed to try harder to fire. after days of cranking on jumper cables it started to run... on 2 or 3 cylinders. i had white smoke like crazy. if i touched the throttle it had no input ( despite being drive by cable 04. 5). It loped really bad ran quieter than stock (this truck had 5" downpipe no mufflers 7" stacks btw) and if the engine was bolted between the frame rails it could have literally walked like a human down the sidewalk it shook so bad while it loped.



any who. my issue was rust in the fuel system. it had gotten contaiminated by a vandilist putting "additives" in my tank. this caused rusting. the top cp3 was trash and apparently been hangin in for the ride. the rust flowing through the injectors hogged them out from 120hp nozzles to 250 nozzles. the stock bottom cp3 was still good. and *** everyone knows 90 hp is the biggest you can go on a stock cp3... the transfertubes were shot. the pressure relief was stuck open slightly. and the cylinder head had rust scaling on the return side of fuel system leading from injectors to banjo bolt in back of head. which connects to fuel rail. AKA TRASHED fuel system. also when i had the head of 3 pistons were melted. probably from too big of nozzles no lack of fuel pressure and hanging open combination. 4 months later im still in battle with insurance company to repair my truck under vandilism.



I suggest you remove your transfer tubes and have them and the injector pump inspected. if transfer tubes show signs of issues like rust remove all 6 injectors and fuel rail and have it all tested at a bosch authorized repair facility (typically a Truck Shop). if transfer tubes dont look right to them under close inspect replace. if pressure relief valve not right then buy a new rail as its cheaper than just a pressure relief and comes with new rail sensor which improves driveability. i learned that lesson the hard way. . the sensor alone at dealer cost 480 and complete rail from II is 200 something. but your problem is fuel related