No Electrical - Troubleshooting Help
 

Hey Team,

Did a bunch of searching but I'm at a bit of a loss as to what to search for specifically.

85 GSL, stock sat for a year - was properly stored like every winter, just a longer sit. Put a good battery in, went to fire it up. No luck - seemed like it was low on power. The interior light lit up, but pretty dim and the dash lights with the key on came on but barely.

Figured battery was shot to hooked it up to boost it - NOTHING. Lights didnt get brighter, won't crank, won't even fire the solenoid. When you turn the key to start, all the lights flip off (like you drained the system).

There was more than average corrosion/that white acid power on the terminals when i took it out of storage but I cleaned them up really well. The fusible links are good. From what I can tell, the fuses look good. Seems like I have some major short somewhere.

Any tips on where to start? Or easy things I may have missed?

Jesse

Check the grounds on the main negative cable. One on the drivers shock tower and the final connection near the starter. Worth disconnecting and cleaning.

To rule out the battery, you can do a voltage check to any good body point that is bare metal.

The grounds are important (*don't use sandpaper, use metal files), but also check the resistance of the Positive and Negative Cables, as internal corrosion will be covered up by the insulation and not visually apparent. Your symptoms sound like a dead battery, though.

^Do this, put a number to the voltage.

New battery cables!
These can hide a litany of electrical gremlins. Guessing yours may be original???

Stu A
80GS
AZ

Are the battery and ground cable available new anywhere, or do you need to make your own?

*Edit - I just checked and both MazdaTrix and Atkins have the pos. cable (12a) but the neg. is NLA.

What I do for the cables is to get 48" pos and neg and then two 24" ones. I run the 24" pos to the fusible link block and the 24" neg to the shock tower. I attach them to their respective battery terminal via the bolt to tighten them down. If you want an extra ground, the alt long bolt to shock tower is a good point topickup.

I should also note, get the cables with the built in ends. Unless you have to proper crimping tools for large gage cable, they won't work well.

Thanks for the feedback. I will definitely check the wires - i did not think to do this.

It does mimic a dead battery but is not. Both batteries I tried were >12V, came out of operating vehicles AND I also tried with boosting off of a running vehicle which made no real difference so it seems that there is either an electrical "flow" problem - cable checking makes sense, or a massive parasitic drain somewhere (which seems less likely). I have a ton of grounding, so I'm not confident on that but definitely could be positive cable.

Will report back once I get a chance to get out to the car and do some more testing.

Any good auto elec shop will make one for you-

Stu A
80GS
AZ

Also when checking grounds, remember that the ground is achieved through the threads of the bolt and the captive nut behind it. In the case of the negative cable ground, the threads of the bolt and the corresponding threaded portion of the rear iron.

The threads should be clean on both ends as well as the terminal that is being secured. I usually tap the receiving end and if the bolt is really rusty, I replace it. Otherwise, a quick cleaning on the wire wheel usually does the trick.

Bit more troubleshooting. The thing is in a seacan so its a pain in the ass so I do small snippets here and there. As well, I've been focused on the build of our racecar for the end of the month (also a 1st gen).

The main power and ground to starter are A-OK - No resistance (0.3 ohm, which was the 0 value on the meter for a closed loop).
The small (10 AWG maybe?) power wire to the fusible link is A-OK as well.

What are the odds something in my ignition switch is fried?
What is the best way to troubleshoot from the fusible link tower to the ignition and the ignition to the starter?

Does the wiring go through the ignition switch prior to powering up the gauge lights, door buzzer etc?

Trying to figure out what my next direction is when I actually pull it out of the seacan and throw it up on stands.

Thanks team.