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94 Safari says it's doing 100 mph standing still.

1K views 8 replies 3 participants last post by  Big_kid 
#1 ·
My daughter was driving the van and said the speedometer pegged and hasn't gone back down. It's an analog gauge.

It's still running normally so I'm assuming it's not the VSS. I'm wondering if anyone has had this happen and could offer some advice. Thanks
 
#3 ·
Codes? 94 was OBD1, pull any codes with a paper clip on the 2 top right terminals in the connector. Install the jumper, key on, engine off, codes will flash starting with 12.
 
#4 ·
Now that I've had a chance to look at it the engine starts but wants to race and it has no power to the dash at all. No idiot lights, the speedo is pegged and all the other gauges are frozen.

It's getting too dark to mess with it tonight so for now that's all I have.
 
#6 ·
Ok, I was able to power up my 1320 box with my jump start box and there were no codes but the alternator is only putting out 9 volts. I checked the connections behind the battery and everything seems intact.

I'm pretty sure the alternator is cooked but that doesn't explain the dash issues and the 1,900 rpm idle speed.

Next I guess I'll pull the instrument cluster and see if there's a short or something that could be the cause. I've never had an alternator go out and take the instruments out with it.
 
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