Trans Am Information > Electrical

1978 T/A has gone dark...

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To preface this post:
1) I know enough about electrical systems to be dangerous and so far have avoided getting zapped.
2) a FITECH EFI system is installed on the car.

The car has been sitting since late last fall and I needed to move it out of the garage to make room to bring my truck inside to do an oil change and tire rotation.  So a couple of days in advance I put a trickle charger on the car to bring the battery up.

The day of maintenance rolls around and I pull off the car cover, hop inside (dome light come on), put the key in the ignition (buzzer sounds) and turn the key to let the EFI prime (without starting the car).  After the fuel pump stops, I turn off the key and repeat the prime (have to do this a couple of times when the car has sat for a period of time).  When the fuel pump stops I turn the key farther to start the car.  Nothing happens - dead silence.  Dome light isn't on and the key buzzer is silent.  Headlights don't come on.

The battery charger shows the battery has a full charge yet everything is dead.  What has happened?  Where do I start looking?

Is there any extra relay or similar added to power the fuel pump on accessories mode? The stock system isn't setup for much more than warning lights, it could be quite a draw especially if it has been parked and more fuel, longer to prime. But that's only my take based on nothing. So depends what fuses, stock or added, may have been affected, or fusible link involved.

Thanks for the reply. 

There is a power lead that goes to a switched circuit in the fuse panel and a fused power lead connects to the positive terminal of the battery.  So I'm pretty sure the fuel pump is not powered through the stock wiring of the car.  The system was installed several years ago and this situation is a first.

I haven't traced wiring yet but I don't see references to a fused link in the owners manual or the 1978 service manual.

The stock starter was experiencing heat soak issues so a couple of years ago I replaced it with a mini-starter that has worked great. 

Visited with my mechanic friend on Thursday and he mentioned several probable issues.  The more we talked through things he kept coming back to the battery being bad.  So yesterday I raised the hood and disconnected the battery cables.  The negative terminal was clean but the positive terminal was caked with corrosion.  Pulled the battery out of the car to have more room to clean the terminals.  Then put the battery charger on it while I cleaned up the cable ends.  I really dislike the side mount terminals as they hide any corrosion that may develop and are a PITA to clean.  When I first connected up the battery charger the meter read 90+ percent but by the time I was done cleaning the cable ends it had dropped to 25 percent and the charger was very warm.  So guessing the battery is indeed bad.  So sometime this week I'll take it down to my mechanic's shop and have him load test it. 

I'll report back on what ends up happening.


Today I took the battery to my mechanic friend's shop and he checked it out.  His test determined that the battery had failed internally so I took it back to the NAPA store I bought it from.  Since the battery was less that 2 years old they replaced it under warranty.

Over the weekend I'll install the new battery.  Appendages crossed that the car will fire up. 


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