Redfox340 Posted May 12, 2008 Report Posted May 12, 2008 "...Holy ish! I'd never thought I'd be back here!" Hi all, it's been a LONG TIME since I've checked in... Got a tech question on hand which I'm having a issues on. Engine: 1988 - 2.8L MPFI V6 (200K miles! Woot!) Symptoms: car will bog and immediately stall if throttle is quickly pushed past idle... RPM's can be ramped up VERY slowly, but will hesitate.. Diagnosis: Have checked fuel pressure - 40psi running --> fuel pressure good Thinking it's a problem with the ignition due to the car almost has a miss at idle. Checking plugs and wire resistance tonight... but have an inclination it's the ICM (ignition control module)? I've got a cheap, generic service manual and need to know the testing procedures on the ICM (voltage, current, resistance). Can anyone supply that info? Thanks a bunch! - Erik (da'Fox!) Quote
BXX Posted May 13, 2008 Report Posted May 13, 2008 injectors or ICM/Coilpacks The ICM cannot be tested without very expensive equippment.. Measure resistance on it and you will fry it. Quote
Redfox340 Posted May 13, 2008 Author Report Posted May 13, 2008 The ICM cannot be tested without very expensive equippment.. Measure resistance on it and you will fry it. Even when the ICM is disconnected from the car, and you're taking independant readings? Man, then the o-so-trusted Chilton's / Hayne's service manual I have is misleading... Anyone have the impedence value of a stock 2.8L injector then? - Erik Quote
92 GP Posted May 13, 2008 Report Posted May 13, 2008 The ICM can be tested at pretty much ANY automotive store i've EVER been inside of. It could be a TPS (Throttle Position Sensor). You can do a back voltage check on it and it should show a reading of 5 V OR Also it could be a crank position sensor. Your ignition timing might be hopping all over the place. That's an easy check if you have a VOM. Just do a resistance check on the sensor (this can be done by pulling the plug off of the ICM that has THREE wires, and check resistance between the 1st and 3rd wires) Room temp resistance should be around 900-1200 ish. The CKP is the only sensor that directly affects ignition timing on the MPFI engines that i know of. But yea, the ICM is easily tested at about any auto store. Quote
BXX Posted May 13, 2008 Report Posted May 13, 2008 The ICM can be tested at pretty much ANY automotive store i've EVER been inside of. It could be a TPS (Throttle Position Sensor). You can do a back voltage check on it and it should show a reading of 5 V OR Also it could be a crank position sensor. Your ignition timing might be hopping all over the place. That's an easy check if you have a VOM. Just do a resistance check on the sensor (this can be done by pulling the plug off of the ICM that has THREE wires, and check resistance between the 1st and 3rd wires) Room temp resistance should be around 900-1200 ish. The CKP is the only sensor that directly affects ignition timing on the MPFI engines that i know of. But yea, the ICM is easily tested at about any auto store. No autoparts store can check a DIS module... Ive worked for 2 (AZ and Advance) and deal with Napa, CarQuest, and APC daily... Quote
92 GP Posted May 13, 2008 Report Posted May 13, 2008 are you kidding me? I will go to a store RIGHT NOW and show you a picture of the ICM tester. It also tests p/u coils. I've worked in auto retail for going on 3 years and i check sometimes 5 a week. Hell i took my OWN module to 3 different stores to make sure that they were all correctly showing that it was good and i was pissed because i had spent time on taking it out of my TGP, lol. IDK if AZ has one, but if they did i don't think the people down here at the Autistic Zones would be capable of finding the power button. I worked at O'Rielly and now i work at Advance and we both have the same tester Quote
92 GP Posted May 13, 2008 Report Posted May 13, 2008 http://www.racingjunk.com/post/880147/LOOK-DIS-IGNITION-MODULE-TESTING-MACHINE.html Quote
92 GP Posted May 13, 2008 Report Posted May 13, 2008 That is the EXACT machine that O'Reilly and Advance have Quote
GP1138 Posted May 13, 2008 Report Posted May 13, 2008 REDFOX!! ICM, almost definitely. Check in more often!!!1 Quote
AWeb80 Posted May 13, 2008 Report Posted May 13, 2008 Erik.....is that really you!@@@@@@@@@!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! welcome Quote
Redfox340 Posted May 13, 2008 Author Report Posted May 13, 2008 Erik.....is that really you!@@@@@@@@@!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! OMGHI2U! Yep, in the flesh. Wow, you guys have gone through some good remodeling since I've been out of a W-body. Need to figure out who's still around these parts... posting into wee-hours in the morning. - Erik Quote
AWeb80 Posted May 13, 2008 Report Posted May 13, 2008 I dunno if you remember me....or my GP....it was basically stock the last time you'd have seen it. Quote
Crazy K Posted May 13, 2008 Report Posted May 13, 2008 try this. rule out a TPS by unplugging it and going for a test drive. in my experience, a bad TPS will simply limit how far you can go to throttle, meaing you can never get the car to go past half throttle. Quote
Redfox340 Posted June 9, 2008 Author Report Posted June 9, 2008 roughly 12.6 And that's the problem... Over half of them were reading less than 3.0ohms.. 5 of the 6 are toast. Replacing them and firing up the car. - Erik Quote
Redfox340 Posted January 7, 2009 Author Report Posted January 7, 2009 So... injectors WERE NOT the complete issue. Trace vacuum leaks to a intake manifold gasket... But the rear issue is that with the high mileage, we found than the camshaft lobes are worn on cylinder #6. Which doesn't allow the intake or exhaust valves to properly open... There, in lies the problem of wide-open throttle stuttering. Replacement of camshaft is too expensive; we're running the car until it dies. - Erik Quote
Brian P Posted January 8, 2009 Report Posted January 8, 2009 that's what happens when the zinc additive is reduced to nearly nothing in motor oil. Flat tappet cams suffer. Quote
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