E36 TPS noise - already shielded vref and signal wires

[saturnv7890]

About to buy an engine ground cable as mine is looking pretty nasty. Is there a list of the other grounds?

[e^2]

There is a list in the BMW electrical schematic book. Do you have that?

[saturnv7890]

No but come to think of it I may have seen a grounds list in the bentley?

Where would I find the electrical schematic book?

[e^2]

http://www.armchair.mb.ca/~dave/BMW/e30/

Dig through the correct year and you'll find the section.

[nando]

About to buy an engine ground cable as mine is looking pretty nasty. Is there a list of the other grounds?

there's really only a couple for the engine - one that goes from the engine to the body, and one on the shock tower on the passenger side. there might be one more but that's basically it.

[saturnv7890]

Ooh just found a nice comprehensive article about it:

http://www.rtsauto.com/ground-cable-replace-it-e30-preventative/

I guess I'll be hitting up blunt tomorrow then!

[e^2]

I guess you can't ignore that ground. I have one that goes from the valve cover to the battery tray. No clue if its stock or not. Maybe thats why my car doesn't like to crank over when its super cold outside? Thanks for the find.

[saturnv7890]

Hmm the problem appears to be G103... which is on the passenger front shock tower. I don't remember where this is but I'll look for it!

[e^2]

This may or may not be a problem, but make sure that the ground cable from block to chassis is a multi-braided type or you may have excessive ignition noise. Has to do with skin effect of the wire for the sharp current bursts needed by the coil(s).

[saturnv7890]

This may or may not be a problem, but make sure that the ground cable from block to chassis is a multi-braided type or you may have excessive ignition noise. Has to do with skin effect of the wire for the sharp current bursts needed by the coil(s).

Yeah I noticed the engine ground was starting to look old so I ordered a new one.

We'll see what that and a healthy cleaning of the g103 does for me, I think it should help!

I've also been having problems with a weak spark, could be related to the engine ground, but I figure if it is a coil, it'll be a good excuse to go wasted spark.

[e^2]

Whats the verdict?

[saturnv7890]

Ah right!

Finally got back from a fun weekend, yesterday I went and took a look at G103, the nut was loose!! So every time the engine started up, those ring terminals were just shaking loosely around!! Tightened up the nut (after wire brushing/sanding the contacts), but I havent run the car yet.

Installing wasted spark right now and doing some other projects, once my coils come in from summit some time today or tomorrow I can get it all together and run it!

I think that ground was definitely the problem, we'll see in the next few days, I'll certainly be back with an update.

[e^2]

That would make sense since your noise was just small dips in voltage and not spikes typical of crazy ignition noise. Good find!

[saturnv7890]

I guess that's true! The line was otherwise flat.

Lesson learned today: The datalogs can really tell you a lot!

I'll post back when I find out if it worked, and hopefully this thread will help more people!

[hoveringuy]

This may or may not be a problem, but make sure that the ground cable from block to chassis is a multi-braided type or you may have excessive ignition noise. Has to do with skin effect of the wire for the sharp current bursts needed by the coil(s).

No kidding..
time to replace my Pep Boys ground cable.