Volvo 240 Grounding

[jsdevel]

I upgraded my battery cables in an effort to reduce resets. In the process of doing so, I believe I've realized that the factory grounding scheme from Volvo on these 240's has a ground loop. Here's a diagram (if you can call my horrible MS Paint file that ) of my 240's current grounding scheme:

Ground-Loop.png

Am I correct in assuming that there's a ground loop here? I'm grounding my coils, ECU, and Injectors to the block/cylinder head. The car grounds pretty much every accessory to the frame.

[LAV1000]

Yes, it looks like ground loop.

Are you using resistor type spark plugs ?

[jsdevel]

Are you using resistor type spark plugs ?

Yes.

[prof315]

Nearly every European car built in the 80's and 90's is grounded in this fashion and come to think of it so were most domestics.

[DaveEFI]

Nearly every European car built in the 80's and 90's is grounded in this fashion and come to think of it so were most domestics.

I've never seen this. Mine has the battery grounded to the body, and an earth braid running from the same (ish) point on the body to the engine block. If that earth strap fails, the throttle cable becomes the earth.

[jsdevel]

Why would they use 2 paths back to earth? Would it only be noticeable if one of the paths began to develop excessive resistance?

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[billr]

"If that earth strap fails, the throttle cable becomes the earth. "

Nah, the engine can ground through the main bearings and all the drive-line bearings. Redundant grounding isn't a completely bad thing.

OP, the ground loop potential there is pretty low, I doubt that is causing a reset of the MS.

[jsdevel]

Why do you think they'd put it there in the first place? I checked other forums online, and I found that it really isn't necessary i.e. cars seem to run fine without the engine braid strap.

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[racingmini_mtl]

"If that earth strap fails, the throttle cable becomes the earth. "

Nah, the engine can ground through the main bearings and all the drive-line bearings. Redundant grounding isn't a completely bad thing.

Early classic Minis have rubber driveshaft couplings and rubber engine mounts so if the earth strap fails, the throttle cable does indeed become the earth, a nice red hot one.

Jean

[EspeNS]

Do you use the oem LH wiring harness for the MS?
I have tried that a couple of times. In the best case it was just some noise on the CLT signal and crank signal.

[jsdevel]

Do you use the oem LH wiring harness for the MS?

I've ran a completely new harness.

Grounding my ECU & O2 sensor directly at the battery hasn't helped my reset issue. I was thinking maybe it was the grounding scheme before where I was grounding everything at the block that was the culprit.

I believe I can rule out grounding for the issues I've been having.

Here's a new thread based on my new theory: Invalid Closed Loop Idle Settings