Engine Misfire at Operating Temp

[Crossthreaded Nut]

Mudwhistle,

Sounds like you and I have about the same problem. I assumed it was injectors and also assumed that after sending them to Swamp that they would come back "as new", but apparently there is some margin of error possible so I will swap injectors two and three into holes four and five and see if the error follows the injectors. This should determine that it's two faulty injectors, or rule it out completely. Jonathon has been trying to help me diagnose the problem via email for a week. I'll post what I learn from him.

James

 

[DaveBen]

The clearences get looser with heat. That may account for the noise with more engine heat.

Dave

 

[Crossthreaded Nut]

This morning it ran better than it has the entire time I've owned it....5 months. It was a cold morning, maybe 28 f and apparently was building a little more injection pressure. I ran a cylinder contribution test and it faulted cylinders 1, 4 and 7. In all of my previous cc tests, it has faulted cylinders 2 and 3. Anybody have any clues to this anomoly? Could it be pointing to a dieing IDM?

James

 

[95_stroker]

Possibly the IPR valve?

 

[goldhilljoe]

James, I had a similiar problem(in neutral, wouldn`t go over 2200RPM hot or cold and in 1st gear when cool and sometimes second gear also-sounded like a back-fire) Other than that it ran great+good fuel economy. Changed all sorts of parts, scanned, un hooked wires to NO avail. Just lived with it cause it still ran ok. Several months ago, I modded the IDM. Problem solved/go figure? I am not saying or inferring that is your trouble. only what worked for me. Good luck--Joe

 

[Crossthreaded Nut]

Joe - did you get injection circuit faults when you performed a cylinder contribution test? I installed a IDM from my '94 F250 and there was no difference at idle however, I ran the cylinder contribution test twice more and it only faulted cylinder no. 3 this time so you may be on to something. Who performs IDM mods now? Swamp seems to have dropped them off of his website and I couldn't find it on Beans site either.

95 - Yes, it could be related to IPR. I replaced external o-rings a week ago and that seemed to make a fair difference in how it ran. It could be that I need to replace the entire IPR with a new one. I may try that next weekend.

Thanks for the suggestions. I appreciate any new ideas.

James

 

[MUDWHISTLE]

I have heard mine make a backfire noise too. same thing I would rev the engine up in neutral and it would do it just once in awhile. I need a place to purchase the resistor for the idm mod and I'm going to do mine. It does not look that hard.

 

[94f450sd]

wich IDM do you guys have?look on the sticker where connector plugs into it.it will say IDM100,IDM110 or IDM120.if you have the 100 or 110 i have the resistors for those.i can also do the mod if for you.PM me about either if you like.i have had mine modded by me for the last few months,since the mod came public.and i havent had a problem yet.

 

[95_stroker]

Sorry to drag this off topic here but...

Rich,

Is there any difference in a modded IDM when running larger injectors and a hot chip as opposed to a stock IDM and jectors and chip?

 

[94f450sd]

i felt a little harder pull off the line,seems to smoke the tiresa little easier,a little more black smoke.dont know about fuel mileage cu i cant keep my foot out of it .but it did make a noticeable difference.