[BMWaufKS]

Hmmm ... I'll have to look again when the X3 returns tonight. Didn't remove the cabin air filter tray, etc. to see it? Where is it relative to the MC? (front of = toward grill, etc.)

I see a wire that's behind and above the booster that's grounded to the firewall -- it's inside black convolute tubing. I don't know where the other end is attached. Is that the one? If so, where does its other end go to? Thanks.

 

[abscate]

It's the underneath ones that give up the ghost, getting exposed to water , salt, dead bodies, etc

 

[jdauria]

Can someone post pictures of this?

 

[dukedkt442]

I see a wire that's behind and above the booster that's grounded to the firewall -- it's inside black convolute tubing. I don't know where the other end is attached. Is that the one? If so, where does its other end go to? Thanks.

Yes that's the one. Grounds that module next to the booster. But that should be in fine shape. It's the lower two the rot.

 

[dukedkt442]

Can someone post pictures of this?

I posted pics of my rotted engine strap in a previous thread is started on this issue.

 

[BMWaufKS]

Exhaust ground strap here and installed; one Doh!

Here's a comparison pic of the engine (RHS, between engine block and frame, behind FR tire and up under the aluminum reinforcing pan) and the exhaust ground (earth) straps.

I had replaced the engine strap previously (see my prior post in this thread; in pic is the spare of the same that I bought) and this morning replaced the exhaust strap. Maybe a slight reduction in start-delay with both installed.

Both aftermarket straps came from eBay sellers (one advertised as 16 in., the other 6 in. long) and are heavier-duty than the originals. Both sellers were slow to ship, and I had to nag the second one to get him to ship despite him printing the shipping label days before.

All four straps test as near zero Ohms resistance, and neither of the OEMs were cracking but the exhaust one's terminals were more corroded.

Worse, this morning and despite the WD-40 spray-down, the exhaust pipe's stud broke off (crossmember-end bolt for the strap came out fine). Looking at the snapped stud, inside had some rusty areas! I deduce that the stud was over-torqued and had cracked a bit letting in some water and air over the years. But there was still plenty of unaffected steel for conducting electricity, I think.

Getting the remaining stud out of the little L-bracket that's welded to the pipe was challenging especially since I didn't jack up the X3. I had to grind the bottom (broken) part of the stud down (well ... up) to the bracket, but it still wouldn't pop up out of the bracket (must have been pressed in originally). So I had to grind off the top of the stud then gently whack the remaining plug out of the hole without flexing the L-bracket too much. Then drilled the hole out to 1/4 in. to clean it up and to make room for the new, bigger bolt. The new, shorter exhaust strap (had to drill out one end slightly like the other strap) went in well in sort of an s-curve shape between the two mounts.

 

[LVyork]

I had the same problem. I swear my car has its own emotions because it decided when it wants to start. It got worse over time though. At first it was a delayed start then after a while it wouldn***8217;t start at all.
Of course I took it to a BMW dealership here in LV to get it checked out. They told me my keys were just old and needed a new one. Well got the new one in and didn***8217;t fix anything. They are saying they can***8217;t refund the key because it was made just for my car.
So I dropped it off this weekend and hopefully they can get this figured out again.

 

[abscate]

Very few of us have a good enough ohmmeter to measure a ground strap resistance, it’s easier to measure potential at each end if you can get some current running through it,

 

[Doug Huffman]

Very few of us have a good enough ohmmeter to measure a ground strap resistance,

No one has that 'ohmmeter', there's no such thing. The proper instrument is a 4-wire Kelvin Bridge.

https://en.wikipedia.org/wiki/Kelvin_bridge

 

[BMWaufKS]

No one has that 'ohmmeter', there's no such thing.

Um ... that article itself references the ohmmeter article: https://en.wikipedia.org/wiki/Ohmmeter

If this page is correct, the term has been in (correct) use since 1895:
https://www.dictionary.com/browse/ohmmeter

 

[Doug Huffman]

Weell, I was going to tell the story of the custom leads that I made for when I frequently used a 4-wire bridge. They were a meter long, plaited just like y***8217;all***8217;s ground straps, and made of silver metal with fancy screw clamps and silver soldered German silver ring terminals. An ohmmeter cannot measure resistances comparable to the resistance of its leads. But you can go on thinking ...

 

[BMWaufKS]

An ohmmeter cannot measure resistances comparable to the resistance of its leads.

Hmmm ... isn't that why we short the leads and zero the gauge before taking the measurement? :dunno: