htulrich

This is for my father in law. The alternator mounting bolt broke we replaced it now when you start the car the tach will work for about 10 seconds during that ten seconds the fuel pump relay behind the glove box is clicking and the battery light is on. After about 10 seconds the relay stops clicking and the tach stops working as well as the temp gauge and the battery light goes out. The engine keeps running but itacts like it has a severe miss about every 2-3 seconds and in turn it has severely diminished power. Also the pcm will not communicate with the scanner (mac mentor I believe). Here is a list of things we have done:
Pulled the pcm and sent it out for repair, sent back they said that it was fine.
Checked alternator checks out ok. 14.1 volts output.
Checked connections to the crank sensor cam sensor and alternator.

Anyone have any suggestions or info on this I have found threads but never any resolution to them. Any help is appreciated Thanks in advance
Hans

lazlong

Sounds like a bad connection somewhere. check for bad connections or wires anywhere near where you were working. Also check for bad grounds.

gearbox

iTrader: (95)

ive seen an improperly grounded alternator fry an ecu before (mounting bolt is the ground). see if you have a spare ecu you can swap in for the same year and model and trans type. if you say it isnt communicating, thats a good indicator it went bad.

htulrich

Ecu was checked they said it was ok I'll recheck the connections and the grounds. What controls the tach? What energizes the fuel pump relay?
Thanks
Hans

lazlong

The ECM/PCM but, those circuits ground at G101, which is here:

That's the top radiator hose on the right and the airbox in my hand.

htulrich

Been a few days since I've been able to look at it. checked and cleaned the ground (g101) no luck I don't have another pcm laying around but we did send this one off and they returned it and said it was OK. They could be wrong I guess. Maybe I'll try to get a hold of them and see how they tested it any other Ideas.
Thanks
Hans

Radianceautospa

Has this been resolved . I have the same exact issue

Dangerousjordan

Any word on this? I have the same problem as well.

Dangerousjordan

I checked my alternator and my top bolt was loose and the alternator was just loosly hanging. Replaced the alternator and got a new PCM programmed and all is well.