JeffEzack Posted February 9, 2005 Share Posted February 9, 2005 I am working on a 2003 F-250 with a 7.3 in it. It is running rough, performed contribution test, flagged injector #8. Replaced #8, still running rough, performed engine basics (compression test, etc, even removed valve cover and observed valve train operation, operating normally). Has anyone had a concern of this nature and if so what was the fix? any help would be appreciated. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted February 9, 2005 Share Posted February 9, 2005 So when you state that you performed all the basics we can assume that you had no DTC's, passed the KOEO Injector Electrical Self Test and did not find any wiring issues? Hmmm, no base engine concerns either and I'll bet the PCED instructed you to replace the injector. I have always been amazed that they never want you to question the IDM. Don't feel bad, this has happened to me and surely many other techs as well. IF you are sure that you have no electrical issues, no other DTC's and no base engine concerns then the Injector Driver Module has to be at fault. It is quite possible for an injector driver to fail and not set a code. Remember that injectors are output devices that are ground side switched by these drivers...drivers are the heat-sunk transistors that complete the injector circuit by providing a ground. This is another one of those times when a test module would come in handy! Quote Link to comment Share on other sites More sharing options...
JeffEzack Posted February 10, 2005 Author Share Posted February 10, 2005 Well I tried the IDM and it seemed to cure the problem until the engine achieved operating temperature. If the truck is at idle in Park or Drive it feels like a small miss and has about 4% on #8 cylinder delta pid. If I raise the engine rpm off idle or cruise all cylinders stay at 0% and the engine runs smooth. Performed oil Areation test - Passed, (changed it anyway), fuel pressure is 60 P.S.I, truck has 26,000 Km and is well maintained, checked to see if there was a later PCM update but it has the latest PCM update. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted February 10, 2005 Share Posted February 10, 2005 So what are you going to do? Are you being overly critical of the idle performance? Just a thought, have you cleared the KAM and driven the vehicle hard for 20 minutes? That is what Ford recommends but my findings are that usually two with a rest period between is better. It definitely improves crank time after an injector repair for sure. Remember that removing injectors introduces air into the oil and fuel system that needs to be worked out and might cause a little roughness. A few customers in the past have told me that it took a few days for their truck to really smooth out... but finally did. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.