Im having a bit of an odd problem.

It started about a month ago when I was driving, all my warning lights turned on. I drove for about another 3 mins and shut it off. I came back to the car hours later and the lights were off as if nothing happened. This happened again about 2 weeks later just as sporadically.

Well today on my way home from school it happened again. I got worried thinking something was up with the alternator and pulled over to check it out but nothing I could spot. So I checked the car out again at home tonight and all fuses appear intact and all connections to the alternator seem good. Voltage as indicted on the stock voltmeter reads at 12v when the cars off and 13.5 while its running. Also, I dont remember the voltmeter waivering when this happened before.

Any other ideas on what it could be or what I can check? If its the alternator, would the lights all turn on before I even start the car?

 

All the warning lights come on if the voltage regulator sense an irregulatiry. For example, they all went on when my alternator belt broke (meaning alternator not spinning/not producting power) and all the lights came on because the voltage regulator knew the voltaged dropped to 12 (or about) and knew the alternator stopped spinning/producing power.

My uneducated guess is some belt slippage that slows the alternator down, and drops is outgoing current. I'm not sure what the volts are on the voltage regulator that set itoff, but I wouldn't be suprised if its super sensitive.

On the other hand, I'm not an experienced technician, just know when you break an alternator belt, that all the warning lights come on. Thats my experience-- and installing new belts.

So I wouldn't be too suprised if your alternator was going out. In which case you should just buy an FD alternator from... The guy that sells him here.

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Dual pullies? I think that probably scratches out my slipping belt idea. Not sure how the standalone may have an affect?

 

Thanks for the information, its definetly led me to a new consideration which would be the wiring for my coolant temp gauge.
We were adjusting it the night before but I think maybe something we wired is causing this voltage irregularity as im not as sure its the alternator at this point. So I'll definetly look into that.

 

On a 86-88 there is a relay in the CPU that turns the idiot lights in the cluster on. This relay gets a ground from the alternator when the alternator is NOT running. That ground pulls a relay in and feeds 12v to the cluster to make the lights come on.

If the alternator does not put out when its running, then the ground from the alternator is put on that afore mentioned relay and the lights come on. If the alternator is putting out....then the relay relaxes due to no ground on it and the lights go out.

Your alternator has two small wires in a small connector. Make sure they are not chaffed and making a ground against some piece of strutcture. On a 86-88 that would be the White/Black wire at the alternator. The Black/White will have 12v on it. Don't ground that one, please.

 

Thanks again. I'll have to pull the UIM to follow the line properly but I'll do so when im back from work.