Help! Mystery Starting Problem (Electrical) '87

[lftrn97]

1987 Kelly Coupe. Before tear the car apart, I thought I'd see if someone recognizes this problem. I have an '87 Coupe with the 305. The I've owned the car for 16 years and was the first to title it. It had 3,000 miles on it in 1992 and now has 22,000. I typically start it every week or so and drive it once a month. I missed starting it for about 6 weeks and jumped it off about three weeks ago (It has the same mysterious battery drain I've seen elsewhere on the forum and even dies when the battery disconnect switch is off!). I went to jump it yesterday and after getting the cables hooked up I got in the Avanti and turned the key and got absolutely nothing. No lights...no fuel pump activation...just dead. The battery was out of date so I put a new one in and still nothing. Checked the "starter" fuse (that fuse box is fun...) and it is ok. Also looked under the dash and can't see any obvious disconnected wires.

Is there a starter relay that I can check or any other fuse/breaker that I don't know about?

I had a GM Chiltons book but apparently have misplaced it. I'll head for the library and copy the wiring diagram for an 86/87 Monte Carlo. But I really would appreciate any advice as to how to proceed in tracing the power path. I assume I should follow the red battrery lead off under the firewall???

You can also email me directly at lftrn97@comcast.net.

Thanks for your help.

Jim Murphy

[Gunslinger]

In most GM systems the starter relay/solenoid is mounted on the starter. There are solenoid relocation kits available, but that's beside the point. Make sure your new battery is good (yes, even new batteries can be bad). Make sure the connections are good and tight...both positive and ground on both ends. Try a second main ground to the frame...even from the engine block. Fiberglass cars are very ground sensitive.

You can have a minor problem or real headaches...from corrosion on main connections to critters having used your wiring for dinner while it sat to a bad ignition switch to who knows what. I don't know if your car has one, but many cars have a main resistor wire somewhere near the distributor and coil or a main bulkhead connector. It's not a fuse but is a wire that will melt and disconnect all electrical power should there be a main short or surge. If your car has a main bulkhead connector, it may have corroded terminals and a full cleaning may cure the problem.

If all your fuses are good, use a test light to make sure you have 12v at the starter solenoid. If you have 12v going into the solenoid, see if there's 12v coming out of the solenoid. If all that checks out, you need to follow the main leads to see where the voltage ends and find the source of the problem.

It should take basic electrical diagnosis techniques to find the problem. Hopefully it will not take too long.

[IndyJimW]

I have a '87 and ran into the same problem. Do you have power at the fuse block? All power comes into the car from one wire that goes to the Amp gauge first and then splits to the fuse block and the ignition switch etc. If one of the wires to the Amp gauge comes off you will have no power to the fuse block or the ignition switch. The amp gauge wiring is push on so its the easiest to check for 12 volts. My problem was between the firewall plug and the Amp gauge at a marine style twist connector behind the heater controls, I bypassed the connector.

The Monte Carlo wiring diagram is only good for under the hood and the ECM, it shows 3 power wires going inside the car but my '87 only has one. The Avanti wiring diagram isn't completly correct for inside the car but is somewhat helpful in showing how Avanti wanted to wire it, kind of....

You can get a copy of the '87 Avanti wiring diagram from Mr. Ernest Edwards at

eedwards0839@yahoo.com.

Good luck,

Jim Wood

[Ernie]

Once you get her going again, I highly recommend getting a "BATTERY TENDER." I got mine on e-bay cheaper than finding one locally.

Battery Tender has a built in computer that will not overcharge your battery.

Before Battery Tender I went through batteries every 18-24 months.