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1990 Supra PCM 351 - electrical issues

S

stankee6

New member
Well here we go again, ran well WED then TH would not start. Manually switched to 2nd battery (brand new), still showing 8 volts on dash. Switch back to original battery, open engine compartment and try to start. Black (negative) wiring EXTREMELY HOT to teh touch and cable bundle smoking! Negative wiring at coil melted insulation. Not sure what is going on. Today (2 days later) volt meter reading 11.5 VDC but will not start.

Coil problem or shorted wires somewhere?

Crappy start to the season.
 
A fully charged wet cell 12 volt battery will read somewhere in the neighborhood of 12.4 volts.
If you are reading only 8 volts, that battery is either very low, or has gone bad.... or your helm volt meter is whacko!

A load capable of heating up the main Negative cable would be very heavy.... perhaps caused by a faulty starter motor.
I can't explain why the Negative wiring at coil melted the insulation.

You'll need to trouble-shoot this from the point of battery connection, to/through your MBSS, and on to the connections at the engine.
Both the Positive and Negative cables and connections.

.
 
RicardoMarine said:
A fully charged wet cell 12 volt battery will read somewhere in the neighborhood of 12.4 volts.
If you are reading only 8 volts, that battery is either very low, or has gone bad.... or your helm volt meter is whacko!

A load capable of heating up the main Negative cable would be very heavy.... perhaps caused by a faulty starter motor.
I can't explain why the Negative wiring at coil melted the insulation.

You'll need to trouble-shoot this from the point of battery connection, to/through your MBSS, and on to the connections at the engine.
Both the Positive and Negative cables and connections.

.
Click to expand...

Found everything under the distributor cap fried, points fused and drew a big surge. Had mechanica replace coil, wiring adn d. cap/rotor etc... all running good.

Now to teh next adventure..
 
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