Rough Idle When Warm??

powerstroker888 · May 5, 2015

So I have been having a rough idle when warm. I have replaced like everything on this truck!! When it's cold it runs great no problems. But when it warms up it idles really weird. There was aeration in the oil so I changed it and it seemed to help a ton for like a day or two. Then it went back to the same old rough idle. This is getting really frustrated. Any advice would be awesome.

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ghohouston · May 5, 2015

have you run a contribution test on it? and if your oil is actually aerating, you either have a bad pickup tube o ring, or the pickup tube is cracked.

powerstroker888 · May 6, 2015

Yes I have. Someone told me my idm could be bad because it was throwing a ton of electrical codes for the injectors. But if an idm is bad then the truck would run bad all the time right?? And how do I fix that??

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mandkole · May 6, 2015

getting IDM codes? you could easily swap one just to see if that's it.

powerstroker888 · May 6, 2015

No not idm codes just like all the injector electrical codes. I guess I could try it. I had a shop check it out and they said my idm was bad. Because it had like two codes for every single injector. So they put a test idm in it and the codes went away. But the thing is is this is my 2nd idm. Not new but used. So who knows.

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powerstroker888 · May 6, 2015

Do you think it could be my ipr??

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Justin@DP-Tuner · May 6, 2015

If you are getting injector codes, it could very well be an UVCH issue. Need to look more into that.

As far as running good when cold but not when warm, that could be injector related. How many miles on the injectors? Ever replaced the o-rings?

powerstroker888 · May 6, 2015

Yes it probably has about 1000 miles on the injectors and the orings are brand new. And the shop also checked the uvch and everything was fine.

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Justin@DP-Tuner · May 7, 2015

Did this issue start when you installed the new injectors, or was it present before that?

powerstroker888 · May 8, 2015

It was after. To be honest it was actually after I did efuel that I started to run into problems.

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mandkole · May 8, 2015

Adding efuel wont create codes by itself, but are you sucking air anywhere? It wont explain cold vs hot idle quality differences, but air in the system will cause a rough idle , poor running operation and is not good for the injectors.

powerstroker888 · May 8, 2015

Ya I know. But it was after I did efuel that's when things took a turn for the worse. I bought the fuel system used, you think that maybe there was stuff in the system that took out some injectors?? Do these issues sound like injector problems??

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mandkole · May 8, 2015

I doubt that the efuel system put anything in your system that wouldn't have already been filtered out. If fuel pressure at the regulator is consistent, significant amounts of air are not likely. Can you see fuel pressure while truck is running?

For me, fuel system and electrical issues could cause running issues hot or cold. The significant cold vs hot oil idle quality change usually points to HPO system leakage (possibly including injector orings, injector oil sides).

powerstroker888 · May 8, 2015

Ya fuel pressure when idling is at 65 psi. But I can't see it when I'm really getting on it. Because the gauge is under neath the hood. I heard that maybe I can turn the fuel pressure down and see if that helps. Like to 60 psi or something. You think this might help??

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Arisley · May 8, 2015

Get a hose, lengthen out the fuel pressure gauge and temporarily zip tie it to the mirror.

powerstroker888 · May 10, 2015

You think fuel pressure could be my problem?? I mean when it is doing it irratic idling I can watch the fuel pressure and it doesn't move at all. I'm thinking it could be the ipr. Also someone said that maybe it could be the icp sensor. Any ideas??

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mandkole · May 10, 2015

Disconnect the ICP sensor while its idling erratically. It defaults to 750psi and will trip the CEL that needs to be cleared. If there is improvement in idle quality, it could be the sensor or the injectors are happier idling at 750.

powerstroker888 · May 10, 2015

It idles the same when I unplug the icp. At first it kindof hiccups alittle when I unplug it then it idles the same.

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