jamieschott

iTrader: (2)

The alternator and coolant fan was the original faults here in this 1992 original TBI 5.0, now 383 TPI. After many days of frustration and inability to drive my car, I have come to thirdgen for some help hopefully.

After looking in the haynes and chiltons manual schematics and tracing those, I found the double wired ring terminal that goes to the starter solenoid to have a ground. I am assuming that this grounded wire is causing the alternator and the fan not to work properly. The schematics that I have found on the net, I found what that these wires go the ignition switch and the power distro ( fuse block, im guessing)

I have pulled ALL wires from starter and pulled them away from K member and headers to verify that there was no burnt insulation that was causing bare wire to rub on metal, everything ok there. The ground does exist in these two wires for sure until these wires go into the big loom that runs under the plenum heading into the firewall. I have not checked from that point to the firewall for ground in these wires.

I have taken the alternator to checkers and had it load tested, to be fine. The car WILL start. When it is running though, the junction block beside the battery that is mounted by the radiator will get hot and start to melt wires. From the grounding issue described earlier, I am assuming.

My question is COULD the ignition switch OR the starter enable relay cause this problem and still allow the car to start?

Any other suggestions or help would be greatly appreciated.

ACCLR8N

iTrader: (8)

Not likely. Starter should have all red wires on the large stud connected directly to battery. Nothing any other color. There is a ground stud on the block, with black wires. Make sure it didn't get pulled down to starter. Single purple to small stud on starter.

Check ground from battery. Sounds like you are flowing a lot of current somewhere.

jamieschott

iTrader: (2)

I will look into that.

I do have 3 red wires that go to the big terminal on the starter.

For clarity of explanation I will call them Wire 1,2 and 3
Wire 1 comes from the pos terminal on battery.
Wire 2 goes to alternator terminal S.
Wire 3, Which has two wires crimped to one ring terminal. one of those wires go to the ignition switch ( thru fusible link B) and the other to the power distro (thru fusible link A )

I checked all wires , including the purple wire, disconnected from the starter. Wire 3 was the ONLY one that was grounded. On either side of the fusible links in that circuit. Up to where this pair of wires goes into the 2 inch wire loom that runs under the plenum , both wires are grounded. I have not traced or checked these wires any further than that, as of yet.

ACCLR8N

iTrader: (8)

Next I'd check the forward junction by the radiator. Unhook them and see which is grounded. Be careful they are hot.

Then try unhooking the under hood relays and see if that gets rid of your short.

If that is inconclusive: Its a pain, but if you disconnect the driver side firewall pass through you will be to determine if the short is in the engine bay or the interior.

BigBadLou

iTrader: (3)

If you say that the distribution block by the battery is getting hot, I'd blame one of the circuits that's connected to it.
Those are:
- coolant fans
- fuel pump
- ECM
- alternator

I'd recommend:
- disconnect all wires from the alternator (make sure that the red wires do NOT touch ground - insulate them temporarily)
- remove cooilng fan relays

If you still see the problem, the last possible circuit it the fuel pump and ECM branch. But you can't run the car without them. But my bet is on the alternator or fans overloading the circuit.

I'd also check whether there is another wire attached to that junction block, maybe from the previous owner.

Also, an important question: does the junction/distribution block get hot with the key on but engine off? Or does the engine have to run for the problem to manifest itself?

Let us know. You got me interested.
Lou

jamieschott

iTrader: (2)

The starter wire is the one that is grounded from the junction block. The one that pigtails off the positive battery cable. I did unhook the firewall pass thru. The ground went away. I disconnected the ignition switch to find that the pink wire and the brown wire in those connectors are grounded also.

jamieschott

iTrader: (2)

Thanks for the suggestions Lou. When i get the battery back from checkers I will try this. I went to have them load test it and the voltage was too low, so they kept to charge.

jamieschott

iTrader: (2)

update... Just got battery back from Checkers. It is bad, wont take a charge. Funds are low right now to get a replacement. So when i get a new batt on tuesday, i try again.

ACCLR8N

iTrader: (8)

The starter wire was getting a ground from the Y that also went to the firewall pass through. Are the red wires going into the the ignition switch showing a ground. Try unplugging the fan relay. The fan does spin by hand?

jamieschott

iTrader: (2)

the red wires into ign switch are not showing ground with firewall pass disconnected. the fan does spin by hand and it does operate when applying temp 12 v power and ground from the battery. the fan relay was unplugged when i did this.

would the battery be causing or cause this. as mentioned earlier the batt is not taking a charge. it is a red top optima.

jamieschott

iTrader: (2)

Changed the battery to humor the situation... All faults disappeared! Car ran for 15-20 minutes and ALternator was charging at 14-14.5 volts and the fan came on and off 3 times. THen the vehicle just stopped. im at a loss for words now