Something to think about July 26, 2012, 09:16:22 PM Here is the issue at hand. A good customer of mine called the shop this week. He said his 95 MUSTANG GT 5 SPEEDER COMPLETELY STOCK just lost a great amount of power. He explained it would run at app 30 MPH and when he gave it gas it slowed down??? With this he drove it for a couple of miles and stopped at a near by gas station. The mechanic could not scan the car. So my customer started the car and proceeded on. After the restart the car ran perfectly??? So where to look??? Well i called the customer today to get more info. He explained to me that when he shut down the car and took the key out of the ignition the ALT light stayed on!!! He also stated the clock was intermittent. I think i know what is wrong with the car and will check it tomorrow. Any one want to guess what it is??? I plan on fixing it in the AM. Any guesses will be appreciated and like i said i think i know what is wrong. Thanks!! Quote Selected
Something to think about Reply #1 – July 26, 2012, 10:43:09 PM The ignition switch is the common point between the clocks accessory power and the charging system light on the dash. Fuse 18 (charge lamp) also provides power to the pcm power relay in the ccrm and everybody knows how it goes with those. Of course if the pcm power relay was going down, you'd be losing the supply and trigger to the fuel pump relay as well. It would be pretty easy to be getting a poor enough supply of current to the ccrm that the relays will flutter and cause the pcm power and fuel pump relays to impose a simulated duty cycle down circuit. Although I think this would affect the FP relay more that the PCM relay since the FP relay is down circuit and would have less current available in a situation where there were, say, high resistance in the ignition switch. So maybe the PCM relay would hold and the FP relay would flutter, and we get the fuel pump duty cycling and limiting available fuel supply. Once we come to the point where we don't trust the ignition switch, we can assume that its possible that in the off position power is being sent through fuse 18 when it shouldn't be. Once he cycled the switch off then on, he's opened and closed the circuit again, and reseated the wiper in the switch. My guess is a melted or otherwise borked ignition switch. Just a guess. Forgive me for rambling, just thinking while I type. Quote Selected
Something to think about Reply #3 – July 29, 2012, 09:16:35 AM May I guess that by the lack of further response, that we got it? Quote Selected
Something to think about Reply #4 – July 29, 2012, 09:25:36 AM My other guess would be a bad ground or little green gremlins Quote Selected
Something to think about Reply #5 – August 08, 2012, 11:31:25 PM Fuel pump. So far the car is OK. But i am keeping my fingers crossed!!! Quote Selected
Something to think about Reply #6 – August 09, 2012, 12:32:45 AM My ignition switch caused the same issue. It would run great, then it wouldn't. Quote Selected
Something to think about Reply #7 – August 09, 2012, 05:59:51 AM We can't assume that there is ONLY a single problem. Tom indicated that the fuel pump was the cause of the running poorly problem, but a failed pump wouldn't cause the ALT idiot light to remain illuminated with the key out, nor would it cause intermittent clock. With the history of the fox bodies, I would look into the ignition switch and the associated wiring harness. Quote Selected
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