CNBZ34 Posted January 2, 2007 Report Share Posted January 2, 2007 Happy New Year Folks! Problem is with my 92 Z34…… This is a 50/50 problem. 50% of the time, car runs awesome and the other 50%...I'll describe below. Start it first thing in the a.m. and it'll idle fine then after a couple minutes, idle will get uneven and erratic. A few taps of the throttle and seems okay. I will make the drive into work, pull up to back into a parking space, shift into nuetral on my way to reverse and it will stall. Fires right back up and things are fine. This is just one example… Something that happened several weeks back and not happened again since…. Went to start it after sitting a few days….fired it up and it was missing horrible, running like shit! Shut it off, waited a few minutes and crank but no start. Looked under the hood for anything loose and disconnected which I found nothing. Made sure that all plug wires were connected tight to coil pacs…all good. Waited another 1/2 hr and tried again and it fired up and ran okay. Weird! That only happened the one time. I very recently replaced the TPS and IAC. Throttle body is spotless clean. It has AC double platinum plugs and Beldon wires with approx 20k. I'm not sure of any trouble codes as my MIL bulb appears to be burnt out. Need to replace that but waiting till I do my turn signal switch. Any help or suggestions would be VERY appreciated! Thanks! Quote Link to comment Share on other sites More sharing options...
FordBoy Posted January 2, 2007 Report Share Posted January 2, 2007 Is it showing any codes? Does the serv. engine soon light come on? If so Try checking the Coolent temp. sencer. Quote Link to comment Share on other sites More sharing options...
CNBZ34 Posted January 2, 2007 Author Report Share Posted January 2, 2007 The bulb for the check engine light is burnt out. It does not come on even when starting the car. I have a code checker for the car, I suppose I need to check it. Weirdthat it is an intermitten thing. Quote Link to comment Share on other sites More sharing options...
1990lumina Posted January 2, 2007 Report Share Posted January 2, 2007 Sounds like one of your coil packs is a bit weak that one morning when you first started and it ran like shit...I had this happen this fall when I changed my thermostat..spilled some coolant so I dump 5 gallon bucket of water all over the engine bay to wash ALL coolant off because it smells like shit when it burns. I got the coil packs soaked..and yeah, the car run like ass for 3 minutes before the coil tarted firing again...funny my SES engine didn't come on lol...wow OBD1 isn't very sensitive to misfires lol Quote Link to comment Share on other sites More sharing options...
pontiac6ksteawd Posted January 2, 2007 Report Share Posted January 2, 2007 Sounds to me like he might have a leaking injector/injectors. Thats the only thing I can think of to make it start up so badly after sitting awhile. Maybe a faulty FPR thats not allowing the fuel to be recylced back to the tank properly. Other than that, I know alot of people have said that these early gen motors are not setup for the expensive plugs. I tend to agree with them... Quote Link to comment Share on other sites More sharing options...
CNBZ34 Posted January 2, 2007 Author Report Share Posted January 2, 2007 Actually, 92 3.4's called for platinum plugs OEM, but my Z has a 97 crate engine and it called for double platinums. Really all the difference is how often i need to change my plugs. It is sounding like a weak coil(s). I'm thinking of changing all 3 along with the ICM. if I had a leaking injector, it would do it all the time. I went thru that with my Trans Am GTA. Funny thing is, when i had my alternator fiasco, the battery was disconnected for about 8 days. After she was back up and running, it was the best it ever ran. Then the idling issue returned gradually. i just hate throwing parts at the car and i don't have access to the snap on scanner any longer from my old job. Quote Link to comment Share on other sites More sharing options...
FordBoy Posted January 2, 2007 Report Share Posted January 2, 2007 Mabie not it is possible that ist does it when it wants to. My car only has a miss at idle or lower once i hold the gas down the miss is gone. Quote Link to comment Share on other sites More sharing options...
CNBZ34 Posted January 3, 2007 Author Report Share Posted January 3, 2007 Kinda thinking that I really need to hook it up to a scanner, maybe a scope too to look at the firing patterns. A new set of coil pacs and an ICM is a little too expensive to throw at it and just hope that fixes it. I just had hoped that someone else had experienced the same thing I did and new the fix. Quote Link to comment Share on other sites More sharing options...
Marchi1 Posted January 3, 2007 Report Share Posted January 3, 2007 can't teh geniuses at Autozone/Advanced/Murrays/Checker check the ICM and see if it is okay, and there should be a way to check the coils as well if I rememebr correctly, in the Chiltons repair manual..... Quote Link to comment Share on other sites More sharing options...
FordBoy Posted January 4, 2007 Report Share Posted January 4, 2007 can't teh geniuses at Autozone/Advanced Are you on crack the SOME people that work at these places dont know jack shit. I was helping a friend change a starter on his 302 for his '85 F200 (custom name custom truck). We got it out took it back there (from there a week ago) we asked for a new one. "no we'll test it. This thing works just fine. Go put it back in and fire that truck up." We drive back the 30mi put it back in it STILL wont work not even a sput sput, klank. So we drive back again they say they will test it again i said no im not driving back out here again.So we got a free replacment a repo yay. went back put it in worked fine started right up. The truck is a f250 with f150 1/4 ton axles hence f200 (his dumbass idea ) Quote Link to comment Share on other sites More sharing options...
CNBZ34 Posted January 4, 2007 Author Report Share Posted January 4, 2007 Well, after some trouble shooting and just plain old investigation, I discovered that the EGR valve was malfunctioning. Had a code 32 stored and after driving it with the Snap On scanner hooked up, I watched the pids on the EGR function and it would work, then fail then be all over the place. $215 later, car is back to running AWESOME!!! This all makes total sense as if it were stuck open, HUGE vacuum leak hence the severe miss at idle I described and also the on again off again rough idle. Lesson learned again.....trouble shoot and spend time to save $$ on the other end. I'm glad I didn't throw coils and an ICM at it! Thanks for the responses! Quote Link to comment Share on other sites More sharing options...
prariedom Posted January 5, 2007 Report Share Posted January 5, 2007 FYI...in OBD 1 engines, the ICM runs independently of the ECM, and the ECM only gives codes for those things it can sense as being wrong according to the sensors. To put it differently...at start up, the computer sends a steady signal based on rpm only and controls spark directly (closed loop), then once operating temp is reached or rpm's/throttle angle go over a certain threshhold, all control is passed off to the ICM, which does its calculations based upon info from the crankshaft sensor and feedback from the O2 sensor, amongst other info passed to it by the ECM. The ECM passes info to it and simply assumes it is doing it's job, as the info is not passed back to the ECM. This can be a good thing, I've learned...if the engine is doing weird things but there are no codes and fuel is within specs, you can pretty much guarantee something's up with the ICM. My Celebrity Eurosport had a 2.8 that would work until it reached temp or until you stepped hard on the throttle, and would not restart until it cooled all the way back down; fuel pressure was good, but once the ignition went bad, the injectors would shut off. After snooping I found out that the injector circuit runs through the ICM; if the ICM fails or it senses a coil failure, the injectors lose power (sort of like how the oil pressure sender can kill the fuel pump if it goes bad). Quote Link to comment Share on other sites More sharing options...
ShockTherapy Posted January 8, 2007 Report Share Posted January 8, 2007 my GTP did that right before puking up the FPR and O2 sensor. Quote Link to comment Share on other sites More sharing options...
winterbeater Posted January 8, 2007 Report Share Posted January 8, 2007 Anyone think this sounds like my problem as well? I'm definitely not trying to hijack your thread, broseph. I just don't want to buy stuff that I don't need to. Quote Link to comment Share on other sites More sharing options...
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