kevin phillips Posted January 4, 2007 Share Posted January 4, 2007 got a 2001 f350 7.3 automatic with what feel s like a miss at idle and at times on the road almost like a random plug wire miss .ran buzz test and cyl contribution no codes koeo koer only codes p0478 replaced ebp sensor corrected code but diddn't help miss any ideas thanks,kevin Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted January 5, 2007 Share Posted January 5, 2007 Something important to remember while performing the injector test is to listen closely to the sound of the injectors. The test itself can only determine the electrical condition of the injectors. We can often hear (or fail to hear) "soft" injectors - the spool can't move in the chamber well enough to give the distinctive "BZZZZ". If there is a problem with the electrical part of the injector (or it's circuitry), it will usually show up as an IDM code, anyway. I'm guilty of rarely looking at a scan tool after a buzz test. Let's not forget about the UVC harness concerns that many 7.3s give.... Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted January 5, 2007 Share Posted January 5, 2007 Ahhh, the ratty running 7.3 with no codes or reason to chose a direction. Most of those neglected trucks have some sort of injector degradation but I am also starting to see more and more older trucks with base engine damage. Broken air cleaner housings and loose induction tubes top my list. The turbo compressor wheel is a reliable tattletale that something is "amiss." (pun intended) If you have one of those cylinder cut-out boxes you can monitor mass fuel desired while cutting out your cylinders to identify weak cylinders. I really am mystified as to why the power balance test was removed from WDS and IDS for the 7.3L /forums/images/%%GRAEMLIN_URL%%/smhair.gif The test was probably taken away by the same guy that brought us the CMP tester... that worthless contraption! Getting back to Kevin's dilemma, a sharp random miss sounds like the UVH connector that Jim mentioned. If you are unsure what we are talking about, READ THIS for a detailed explanation. Quote Link to comment Share on other sites More sharing options...
kevin phillips Posted January 6, 2007 Author Share Posted January 6, 2007 i checked the uvc connections no help ended up a hp oil pump concern not building enough oil pressure pressure was dropping low but why diddn't it shut down about 380 Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted January 6, 2007 Share Posted January 6, 2007 hp oil pump concern not building enough oil pressure pressure was dropping low but why diddn't it shut down about 380 You didn't get any ICP codes or see the IPR% ramping up? /forums/images/%%GRAEMLIN_URL%%/confused.gif Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted January 6, 2007 Share Posted January 6, 2007 Just a side note.... I'm not sure if anyone else does it (I know I deal with some "exspurts" that feel they don't need to) but I find that even when I am down to watching as few as 4 or 5 PIDs, I am constantly making recordings.... There can be way too much stuff going on in the screen display for us to accurately (for ME to, anyway). This way we can catch trends that may be too subtle to draw our attention, and we can do it while we enjoy a cuppa.... While we do this, we can also save some of our snapshots of good trucks in the library and use them to compare against problem trucks..... Like Keith opined, if you had a high pressure oil concern, I would have expected to see IPR ramping up to maintain ICP_DES. Once your ICP dropped down to 400ish PSI, I'd think you'd be seeing IPR at over 60%. The line depicting the IPR duty cycle would ramp up possibly slow enough that there wouldn't be a real good visual cue (been there, done that) - a recording would allow us to stare at it long enough for it to sink in.... On edit.... here's some food for thought.... ICP pressure is a computed value (by the PCM). This may or may not be the actual PSI gauge reading that you might see if you had a pressure gauge in the system. ICP volts, on the other hand, is the actual sensor voltage that the PCM sees. I always like to view ICP as both pressure and volt PIDs.... pressure because it's easy to understand - volts because there are times the PCM can get "creative" (or is that "confused"?) trying to decide what to do about some of these concerns. Using the 2001 PC/ED as an example, if we go to the introduction for PPT DC, we find a chart that correlates ICP volts to what actual pressure would be Quote Link to comment Share on other sites More sharing options...
kevin phillips Posted January 17, 2007 Author Share Posted January 17, 2007 thanks for the info,i have a hard time sometimes with the diagnosis i can't keep all that pid data straight i will try recording though now and see if it helps Quote Link to comment Share on other sites More sharing options...
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