engine wiring anomalies (c900)

That is a non OEM cable, my '91 900 does not have it. Also the round yellow terminal on the thin yellow starter relay cable is not original. Maybe it had some issues with the relay or starter motor in the past. Has it ever been replaced?

I would say this is an earth (negative line if you like). Most probably used to connect another component to the manifold and thus to the negative line.

Hmm, ok. The starter motor died (after a long illness) and was replaced within the last year, so it could be that. I suppose I should just spring for a new battery cable. If that's the case, you'd think the guy putting in the new starter would have noticed, but you never know. It would have been in his interest, as he could have charged me parts and labor for a new battery cable.

Yep, that's probably from putting in the new starter (which I had done at an indy Saab place). If the mystery wire from the intake manifold isn't OEM, then it might well be part of an aftermarket security system the car used to have. I've found (and removed) assorted remnants of it from all over the car over the years. I guess I just never noticed it before.

Thanks for the very helpful reply.

John

in article slrndd38i3.39r.rotten_NOSPAM snipped-for-privacy@oragam.example.com, John B at rotten_NOSPAM snipped-for-privacy@ccil.org wrote on 10/07/2005 23:33:

Simply put, get that changed immediately. I had a situation where my radio would go off periodically. Luckily I have a voltmeter gauge in the car which showed the voltage to drop dramatically. The car did not stall.

I found the problem almost immediately - the live wire from the battery had bared off on the turbo battery shield and had welded itself to it. Once the car had been made safe, electrically, I found a number of blue scorch marks on parts of the shield and a perfectly round blue scorch mark on the turbo elbow. A lucky escape ...

Don't risk it ... Just get it replaced.

Paul

Given the current that a starter draws it's highly likely to be a combination of heating due to the terminal resistance where the cable attaches to the solenoid going up just due to age and contact degradation, and also due to that end of the high-current cable being the closest part which is near the heat of the engine when running.

Additionally, the end of the insulation is a point where contaminants, moisture, etc. will 'wick' into the multistrand copper cable over a period of time so that's probably part of it too.

I agree that the small wire coming off the intake manifold is an earth for something. Check the alternator to make sure it's connections are all in place, but to save the wire causing any shorts take it out and replace the bolt. Then, with the wire kept safely somewhere in case it is needed, have a look to see if there's anything nearby which looks like it's had a lug come away.

Regards,

Craig.

Ok, thanks. I've ordered a new battery cable, which I'll put in this weekend.

Yes, definitely a risk for shorts. While I was photographing it yesterday I accidently drew a spark from the hot terminal of the alternator. I've snipped off the wire, and I'm pretty sure I won't need it for anything.

Thanks.

John