88 Fiero - Hard to start when warm - electrical issue (Page 1/2)
06GTO APR 08, 09:16 PM
'88 Coupe, with a 3.4 pushrod and 5 speed in it.

Runs great and overall pretty happy with how it has been running since all the work. Been chasing one issue since I did the swap though.

Happens on and off, and, I don't drive it that much so I don't think if it often. But got it out today and figured it was time to fix it.

It doesn't like to start when warm. Acts like the battery is dead. Turns over slowly, lights dim, clicks, ect.

However, if it let it cool of a bit, starts right up. When it is going through this issue, the negative battery cable (the small one, that attaches to the chassis) gets really hot.

Hot enough, that it melted through the insulation a while back (replaced the cable).

What I've done:
Replaced battery
Replaced the negative battery cable (and small wire).
Cleaned off the chassis ground, and ran another ground wire from the rear of the block (trunk side) to the chassis to make sure the block had a good ground.

Negative battery cable is hooked up to the front of the block, if I remember right, the first stud on the head near the battery.

The melting negative ground tells me there's a short somewhere, but I'm at a lost as to where, especially since it only seems to have an issue when warm.

Drove it around 15 miles today, afraid to stop it somewhere as it might not start again. Lucky, when it was acting up after my drive, I had stopped it in the driveway. Let it sit about 20 minutes, and fired right up.

Thanks in advance for the thoughts/suggestions!
shemdogg APR 08, 10:15 PM
Lotsa folks recommend an extra ground strap from the firewall to the upper intake, that might help. Otherwise maybe starter heat soak making it pull crazy amps when the engines hot.

shem
olejoedad APR 08, 11:17 PM
Starter heat soak.

A short will blow fuses, not make the ground wire hot.
Crasian APR 08, 11:24 PM
Like the above response... starter heat soak and the inevitable no start. There is a battery load tester at my shop and I can measure how much amp the starter draws, but I would personally just buy a GOOD starter from a reputable source and install it.

-Crasian
06GTO APR 09, 07:32 AM
Gotcha, that makes a lot of sense.

Didn't even think of that.

Is it fixable? How do I fix it?

Quick search says make some sort of heat shield, or wrap the start in that heat wrap?

How do those work out?

[This message has been edited by 06GTO (edited 04-09-2019).]

css9450 APR 09, 08:52 AM

quote
Originally posted by olejoedad:

Starter heat soak.




I agree; been there done that with a few different vehicles including my Fiero.
olejoedad APR 09, 09:30 AM
If the starter is old, chances are it's down on power from years of heatsoaking, and replacement may be your best option.
There is a thread on here today about replacement with a later model gear reduction starter that you may find interesting.
2.5 APR 09, 09:35 AM
Yep replace the starter, check condition of the cable to the starter.
06GTO APR 09, 01:44 PM

quote
Originally posted by olejoedad:

If the starter is old, chances are it's down on power from years of heatsoaking, and replacement may be your best option.
There is a thread on here today about replacement with a later model gear reduction starter that you may find interesting.



Starter is new. It was replaced when I put the 3.4 in it (last year). Has maybe 100 miles on it since putting in the new engine. Obviously I don't drive it much.

I have a later model starter that I had originally bought when I put the new starter in it, but it just never quite fit. I'll check the thread.

No issues replacing the starter if necessary, but given it is pretty much new I'd like to explore other options to mitigate the heat soaking vs a new starter.

olejoedad APR 09, 05:46 PM
When you say new engine, is it remanned or rebuilt?