flministock2

Ok, I have a problem with my son's '94 Mustang GT. Bear with me here. A week ago the alternator went bad on his car. I replaced the alternator and a day and a half later the voltage regulator went bad on the new alternator. The voltage regulator started spiking and putting out 18.87 volts. This in turn fried the battery. I immediately replaced the battery and got a replacement for the alternator. Ok, now all that is fixed and it is charging and working correctly (14.27 volts). My problem now is...the car has no power. It just has no pep/get-up and go. I have had the car looked at by (2) different mechanics and both ran computer diagnostics on the car. The only codes that come up say that the left and right banks are running lean. However, when a fuel pressure test was run on the car, it was normal and did not fluctuate when driven. This wasn't a problem prior to the alternator issue and I initially thought that the problem was that something else got damaged when the alternator started putting out 18.87 volts. But the diagnostic test does not support that. As far as the mechanics can tell, there is no indication of a computer problem or sensor problem. I was thinking that maybe the car jumped time a little and I am going to check it tomorrow to see (engine has ~108000 miles on it, tranny has 18000 miles since total rebuild). In the meantime if anyone has experienced this type of problem and can help or point me to some useful info, I would be VERY APPRECIATIVE! And by the way, the car had a complete "tune up" approximately (3) weeks ago.

Thank you in advance for any help received!

88PatrolCar

The only thing that I can tink of is that your O2 sensors are toasted, but you did have a mechanic look at it so....... Did they put a volt meeter on the O2 sensor when the car was up to runing temp? It should fluxuate between 3 and 8 volts.

flministock2

88PATROLCAR....No they didn't put a voltmeter on the O2 sensors, but they did have the computer hooked up and the mechanic showed me the real-time percentages which changed as the accellerator changed. According to the mechanic, the O2 sensors were Ok. I had another mechanic say that the extreme voltage may have fried a fuel injector, but I have my doubts about that since the car is multiport injected and the car isn't missing. I would think the car would be missing if it damaged an injector, don't you think? I only have two other thoughts, either it has jumped a tooth or two on the timing gear or it has somehow damaged the computer module but doesn't show up in the diagnostics. I can see this is going to be a real pain (and costly) thing to fix!

86HOGT

In most OBD I cars a sensor could be some what out of range and NOT trip a code. Get a factory shop manual and walk through the diagnostic tests, step by step.

flministock2

Ok, an update for those interested! 2-weeks and $800 later, I finally have the driveability probe resolved on my son's 94 GT. It seems my little alternator fiasco damaged the "computer", "mass airflow sensor" and "coolant temp sensor". I also replaced the (2) O2 sensors, not because they were a problem but because it was just plain time to replace them. Have no idea when or if they have ever been replace before. In any case, now that the above items have been replaced, it runs like a 5.0 should! At least as well as a stock 5.0 will.

Thank you to all who tried to help with the diagnosis of my problem, you help and input was greatly appreciated.








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