OK, I know this is long, but a former CEG??er from the 90??s has returned to the fold and I could sure use some HELP! I seem to be having some major league problems with my 95Se MTX. Problems started while stuck in traffic on Long Island Expressway. (No surprise about that) Cooling fans will not come on and temp is rising! (NOTE at no time have I let temp get past ??L?of ??normal? on gauge, NEVER into red zone) CEL light coming on and off. Got off hi-way and pulled into a parking lot to check things out. Car stalls out and very difficult to restart. Back up into parking space, car stalls and will not restart. Tried to restart until battery about dead with no luck. Found drivers side cooling fan is seized, but fuses ok. Disconnected battery to clear PCM and let sit for an hour while I get lunch. B4 starting again, I pulled AC Clutch relay so I can get some fan cooling by turning AC to on w/o running AC compressor and putting more load on engine. Back on, hi-way, (Minimal traffic thankfully) Temp ok while moving, climbing when stopped. (This is NOT a water pump issue, I was one of the first to discover that little design defect!) Car surges while driven and when pushing clutch in, RPM's hang around 3500- 4000 RPM for 5- 7 seconds before dropping to 1000 RPM. (Definitely NOT the normal Throttle Hang problem.) Cables inspected and are ok, no binding in linkage either. After approx 15 minutes of driving, engine rpm's SLOWLY drop to 1000 RPM when coming to a stop & clutch is in, and then engine dies completely. Engine will crank but not restart until after engine has cooled.
Temp is ok on highway but rises during stop & go, so flow, radiator, water pump, etc. ok. I rebuilt the seized fan and tested OK . (If anyone is interested, I can post a separate thread on how to overhaul/ fix the cooling fan motors. Not too hard and only costs about $10.00 if you DIY!) Removed black hi speed fan control relay from underhood fuse box, jumpered out and fans came on. (I have schematics for car in Haynes manual.) Tested fan relay and is OK. ECT sensor OK but replaced anyway: no effect. Wiring harness inspected and re insulated at fan connectors, bottom of underhood fuse/ relay box near battery and various other connectors. Have not had harness replaced. IAC cleaned & tested and electro-mechanicaly ok.
I installed an indicator light in the circuit to show power status of IAC. When stall condition occurs after driving a while, IAC loses power at approx 900- 1000 rpm causing engine to stall. Replaced PCM w/ refurbished EEC-IV unit from Signature L.M. (Thank you Bill Jenkins!) This seems to have cured the surging/ drivability problems and the stalling with one exception which I??ll cover below, but the fans still won??t come on!! I let the car sit a couple of days, pulled all fuses (again!) and checked with continuity tester; all OK. Started up and when temp got to ??M? on temp gage, fans come on simultaneously with CEL light! Temp drops to ??O? on gage, (where it normally runs on my car), fans and CEL shut off. Temp rises slightly to about ??R? fans and CEL light back on for a few seconds, go off and do not come back on! Shut car off when temp hit ??A? on gage. Let sit overnight and today, drove car around for a while, (ran ok except for fan problem). Then ran the self tests and EVERY time the fans came ON for a second or two when starting the Key On Engine Off test, so it seems the basic cooling fan circuit is OK. Got these codes:
Key On Engine Off test 1: 111, 542, 543
Key On Engine Running test 1: 543, 543, 538, 538 (but I did ??goose? it!) then engine stalled!
KOEO #2: 522, 522 (maybe forgot to push clutch in?), pause 118, 542, 543
KOER #2 543, 543, 538, 538 (Dammit, I AM goosing it, and it pings like hell when I do!) Engine did NOT stall.
KOEO #3: 543, 543 pause 118, 542, 543
KOER #3: 543, 543, engine stalls. IAC indicator light was on so IAC did not lose power.
KOEO #4: 543, 543 pause 118, 542, 543
Called it a day at that point!
I??m thinking the 118 code (ECT sensor is/ was high or open) might be the result of the temp going up so high and then shutting the car off. With out coolant flow of engine running, coolant temp will rise in the block until the waste heat is dissipated. Then when I turn ignition on, the PCM see the high temp. On the OTHER hand, it could be indicating something I DON??T know. The 542 and 543 codes have me really stumped! I can hear the fuel pump going on and then shutting off when I turn the key to on, so it can??t be not shutting off? And if it has a bad ground or no power, how the hell can I drive the car all the way up to red line without a stutter, stumble or stall! Any thoughts out there ??cause I??m goin?? nuts here!!
