chassis negative cable badly melted, no power to ECU, help me get it back on the road
 

1992 w/180K.

Wife was driving it and she said that earlier, the car sputter a bit when she was getting out of parking spot.

She's at a light and it dies. cranks freely and does not light up.

I tightened the ground wires and it cranks freely.

I did not have time to check the timing belt, will do so tomorrow.

So here's the weird part. The check engine light does not come on when the key is in the on position.

anyone know what fuse or fusible link powers the ECU.

Thanks for the help. Need to get it running ASAP.

my number is three 1 (zero) - to9two - 5tofive9.

BW

Re: help me get it back on the road
 

Here is the diagnosis
Timing belt is fine.
Fusible link 2 is not blown.
No interior or exterior fuses are blown.
Negative lead to the chassis is a melted badly.* Plastic battery tray is melted by the wire and the battery is leaking.* I removed the negative wire and trimmed it until I found clean wire and then put it to a bolt on the frame rail near the tranny fluid filter.* I also replaced the battery.
I still don’t think I am getting power to the ECU b/c the check engine light does not turn on when keyed to on and the fuel system does not power up.* Where does the engine ground come from?* Could there be a bad ground there that is not closing the circuit.* Did I fry my ECU?* Where is the ECU located?
Anyone else have this happen and how did you fix it.
Thanks

Re: help me get it back on the road
 

I think the ECU is under dash drivers side near steering wheel column... but not sure:(

Keith:cool:

Re: help me get it back on the road
 

Please go over the series of events again indicating the order in which they occurred. It is difficult to comprehend the initial advice --- “I tightened the ground wires and it cranks freely.” with the later report ---“Negative lead to the chassis is a melted badly.* Plastic battery tray is melted by the wire and the battery is leaking.* I removed the negative wire and trimmed it until I found clean wire and then put it to a bolt on the frame rail near the tranny fluid filter.* I also replaced the battery.”

Please also confirm that “ Fusible link 2 ” indicates the main fusible link, rather than 30 amp SBF 2.

Re: help me get it back on the road
 

here is the order of events

car stalled @ light. wife tried to restart & engine spun freely.
towed home. i noticed ground to chassis was bare wire (insulation was melted thru)
battery tray & battery housing was damaged by the hot wire. also noticed no cel.
replaced the battery & the chassis grnd

the following is what has been done

1) Replaced the cable going from the battery to the rear of the
starter.
2) cleaned and remounted the chassis battery wire
3) Double checked fusible links and fuses (all good to go)
4) Place a wire from the neg. terminal and placed it onto the ground at
the rear
of the passenger side intake manifold.
5) replaced the ECU w/another ECU from a spare car.

I still do not have CEL or engine start-up.

Anything else someone can think of?

Would the theft prevention system keep the car from starting.
I do not have a remote for it to turn off the alarm.

Thanks

BTW wife needs a car tomorrow so any help would be appreciated.

BW

Re: help me get it back on the road
 

How come the engine cranked OK, but later you decided that it was necessary to replace the cable to the starter and the battery ground?

If the negative wire grounding the battery to the chassis became heated to the point where the insulation, battery tray and battery housing were damaged, a very high current short circuit must have occurred from battery positive to ground.

Everything indicates a substantial short to ground in the lead to the starter, or within the starter. Please advise exactly why you replaced the cable.

You advise that all fuses including the main fusible link remained intact. Therefore the only other possibility is a short circuit at a point in the main battery lead before the fuse box, or within the fuse box bus connections, before the fusible link. A burnt out connection within the fuse box could be the problem, but it is difficult to comprehend how a direct short to ground within the box could be likely.

As you have not mentioned anything, one must presume that all things electrical are OK and presume that the engine cranks OK except for “engine start up“, i.e. the engine will not start/run. Do the fault indication lights illuminate as a test function, as is normal when the ignition is turned on? Are all electrical items functioning normally? :confused:

Re: help me get it back on the road
 

Still interested to help. Have you sorted anything? :confused::)

Re: help me get it back on the road
 

the starter would engage when keyed. Hondasucks mentioned that the overheating chassis ground is usually due to a corroded wire on the starter ground

All other electrical circuits are working ok.

Newest development. The battery ran dead after trying to crank it and testing it. I charged it up and installed it. The CEL came on and the car started up. The power light flashed. Have yet to pull the codes. Wife drove it away and I was following. It died again on the freeway. same no CEL condition as before. Tried fiddling with the battery wires and the fusible link and checked the ground connections. Nothing
I called AAA and had it towed to a auto electric shop. Of course when it arrived at the shop, the CEL came on and started fine. The power light flashed again. It was 10:00 pm and I did not have time to risk driving it around to see what was up with the tranny. Will call the shop tomorrow and see if they can diagnose when is going on.

Any reason something it the tranny would cause power to stop going to the ECU?

thanks

BW

Re: help me get it back on the road
 

up date
just got word from the electrical shop that there is a bad crank sensor 2wire/sensor and possibily something wrong with the engine harness.
will be checking the sensor
and the tcu grounds to see what's up

Re: help me get it back on the road
 

I hope that sensor fixes the problem :),
I've had a cam sensor and a coil give problems. Overall, the Subaru electronics perform well, nearly two-decades in our 92s

Re: help me get it back on the road
 

which sensor is the second crank angle sensor?

is it the top one or the bottom one?

Re: help me get it back on the road
 

Looking from the front of the engine, there are two crank sensors. No 1. is vertical, No. 2 is at a 40* angle. The one on the side of the engine is the cam sensor.

Harvey.