electrical guru's help!
 

My car is busted (1990 TII/ S5 TII) and I need to fix it, the egi fuse keeps blowing and part of my harness is burned. I think its a bad short, but I need to know the best way of going about finding then fixing it. This all started after I hit a large pothole, the car stopped, and several 30amp fuses later I knew I had a problem. This was the same problem I had 5 years ago. (took it to a shop, 1 month and 900$ later I got my car back running) But apparently they did a crap job. I'll be searching the fourms to find any answers I can find, but direct help is always best

thanks in advance for any help

I would look into getting a new engine harness.

Check the harness under the Car,on the driver's side..I'm gonna bet ya that the Starter Wire is Pushed onto the Starter and it is shorting out there...(I am Really Taking a guess at this,But if you hit a Pothole,that is basically the lowest part of the Engine that is Vulnerable).

If part of the harness is burned you need a new harness. The egi fuse will blow when things short out - eg two wires in a burnt wiring harness.

I'm pretty sure I can replace the small section of harness wiring that is burned though its insulation, I think the short made the wiring heat up enough to melt/burn it's insulation. Now it's a matter of finding the damm short and fixing it.

Uh, I think you already found the short. Burned harness? Yeah, a short will do that. That is where the short is. Only thing to look for is why it shorted, as in rubbing against metal, ect.

And pwdrby, you only need one wire to cause a short (and subsequent burnt harness). The chassis acts as the second 'wire'.

Best bet is to replace the harness, as mentioned.

How hard is it to replace the harness with the engine in the car? has anyone here done a harness swap w/engine in car? any first hand info would be great.

I'm considering swapping my engine harness also. I've been putting it off...a little intimidated by it, but it seems pretty straightforward. At the least your UIM will have to come off as there are injectors wires and such under there. I"m not sure about the interior harness that runs behind the dash.

What I"m doing is taking the FSM and taking little tab labels and writing the harness purpose and # from the FSM.

Yeah it's a little scary but I'm up for it (so was changing my broken supension arm)
I've taken the upper intake off many times and changed fuel hoses ect...
My biggest worry is if I can't splice in new wire and re- rap the harness. That buying a s5 TII harness will A= be silly expensive for a new one or B=extremely
hard to find because S5 TII seem to be rare and rarely parted out.

You can fix it by replacing the wire that is damaged. Why do T2 owners not sheild the harness above the turbo? I don't know. My buddy has cooked his harness twice there on his S4. It's been fixed by him twice and yet he does nothing to prevent it. You should fix it then wrap it in heat reflective tape or use some sort of heat sheilding of your choice.

It's not a hard thing to fix just time consuming. The last time they probably used butt connectors or something. You have to solder the connections. If you don't know how find someone who does. I could fix it for you but I'm three hours away from you actually three and a half.

thanks for the support. I don't have a problem doing it myself, I just wanted to know if it's advisable. I have a soldering iron and torch and some electrical know-how. I just wanted to find out if I'm just missing something really easy.

You have to be careful on which wires you are repairing. Don't forget that this harness is was actuates your injectors. You have to be ultra careful to get good, clean well soldered joints. Make sure you read up on how to solder before you attempt this. Bigger the glob != better the job.

I'd remove the harness as well prior to doing this. Make sure you have plenty of room to maneuver to do it right.

Don't replace the harness to fix one short. Way overkill. A decent wiring troubleshooter can trace the short down to the wire or connection affected, and so can you. Show us which 30amp fuse is going, and I'll look at a few wiring diagrams. It could be a short to ground, or a component malfunction.

I'm assuming you have the FSM, but if not, see my sig. for links.

It's the EGI fuse, as mentioned in the OP. Since he's mentioned that there is exposed wires, I'm sure he's found the source of the ground.

Use a test lamp to be 100% of the location of the ground.

Been looking at the wiring diagram...

To further narrow down the source of the problem, try every switch and lever, and also see if any fuses are blown in the interior fuse panel. Which part of your harness is burned?

The part of the harness that burned is near the main relay/ trailing coil. I have not had time to look at it in depth (Have to go to work) I work for a gen contractor so i'll use his fluke multimeter to check for contiuity on the damaged wires. I really hope I can find the problem. Because I dread taking it to a shop or waiting for ever someone to sell me a S5TII harness.

If it's a wire going to the Main Relay or the Trai coil assy, then it's a part of the Front harness.

You need to identify the wire color (black with white stripe{ B/W}) and find out where one end or the other terninates. LIke "the black/white wire terminates at one of the plugs of the Main Relay".

Thanks hailers I've been waiting for one of the heavywieghts to chime in. You and icemark seem to have th most real world experience with electrical wiring. I'll be spending all weekend trying to get the car repaired the right way. I've downloaded the wiring diagrams, and it looks like the EGI fuse feeds the coils & injectors on one lead and all of the solenoids on the other. If thats right I have a starting place to look for problems.

i had the same prob before and as mentioned before my afm,boost sensor ect.... harness had been melted by my turbo hot side . i had to trace it down the hard way and pull wires apart and replace a few sections . I couldnt see burned wires from above engine because it was melted on bottom of harness . i just kept looking and replaced blown fuses and moved wires and one arc showed me where it was .
the hard part is finding the short after that easy fix if its not too badly burned , if just a naked spot just fix that spot easy fix solder and shrink wrap. even a butt connector would work for some time but usually corrode where exposed to moisture and eventually break. Its really up to you and your preferences if you fix it or not. best of luck to you peace out

So I unwrapped the melted portion of the harness, and it looks like 3 of the wires
going to main relay are shorting. So I got a replacement main relay from a junkyard 7 and i'll replace the melted wires sunday. Wish me luck