Fontana

So I wanted to clean the remaining grounds on the car and went for the drivers side footwell. I saved them for last because I figured they have to be in good shape as they are inside the car...Wrong! I couldn't believe how badly tarnished they were. Worse than all the others in the engine bay. Lesson to be learned here is, don't take any of your grounds for granted and assume they are fine just because they are inside the car.

The only grounds I have left to clean are the two above the bellhousing. I was literally laying on top of the intake yesterday after work looking for them and I am a big guy, not fun... I could not locate these grounds. Do I have to get to them from underneath the car? What are these grounds going to and their purpose, out of curiousity?

MainePorsche

You have to remove the fuel pressure regulator, dampener, and connecting line as one unit. They're a bear to get to. They're the ground points for the engine controllers. Here's a pic

Bill Ball

Yep, Anthony, pull the FPR and dampner.

Note that loose electrical plug end in the center of the pic. That's from the crank position sensor, visible to the left of it. On your car it should still be plugged into the harness on a metal bracket below the plastic throttle wheel. Do not be tempted to fiddle with that unless you want to replace it now (not a bad idea but...). Quite often the plugs are brittle and will break apart. If you are thinking of replacing it, if it appears to be in bad shape, remove the Allen bolt retaining the sensor and see if you can pull it out. The one in the picture appears to be partially out already. However, sometimes these are totally jammed and can break off from trying to muscle it out. Then you are facing a conundrum. You would then have to drill it and fashion an extractor OR remove the flywheel - a big task on an S4 automatic. For now, I would probably just leave it alone unless it is obviously bad and you have another in-hand. Just warning you.

If the grounds inside the car were corroded, then these grounds you are seeking are quite likely too, and they are essential to the fuel injection and ignition as Maine mentioned. There are grounds all over the car, including a set above the CE panel, main engine ground at the lower right rear corner of the block, and others. Wally's annual electrical preventitive maintenance details all this.
https://rennlist.com/forums/2220328-post33.html

jeff spahn

Don't forget the stupid ground underneath the intensive washer tank in the cowl. Stupid place for one.

Fontana

Thanks guys. Yes I did all of them except for the two on the bellhousing and the one under the intensive washer bottle

Fontana

Judging by the pic, it doesn't even look like those are grounds. They look like bolts just holding in two clamps. I have to look now that I actually know what I am looking for. Does the FPR and the dampener definitely have to be removed to get to these?

Bill Ball

Yes, those bolts that hold the throttle wheel bracket down to the block also should have ground rings with a bundle of small brown wires attached, although they aren't visible in the pic Maine posted, and the wires are wrapped so you'll just see the ground ring, which will look like a thin washer, and the harness sheath.

If you can get to those bolts w/o removing these, congrats! They are already removed in Maine's pic.

Here's another picture showing the harness grounds with the intake removed too, particularly the one on the left of the picture is most clear, leading back to the main engine harness.

Fontana

Thanks Bill, that looks like a mother to get to. I guess I will be removing some mechanicals...

MainePorsche

Be careful there.
With the intake on, even with all things cleared, these wires will seem very short. If you are to vigorous with them, a (necessary) quality cutting and re-crimping will be the price to pay. Yep, that was me.

Avar928

I was able to clean both of them without removing the dampener or regulator. I used a socket wrench and a very long extension and I believe they were 10mm hex bolts, was able to land the driver side one dead straight and the passenger side at a slight angle.

Wire brush, sand paper and contact cleaner, some Stabilant 22A on the side and presto! Good as new.

The one that was most the pain was the one near the washer tank, passenger side head light. Couldn't get the bloody thing off, had to remove some support bracket for some wires in front of the auxiliary fan but there was no room for a socket wrench. Attacked from underneath the car, stuck my arm from under the spoiler with a wrench and got it loosened up. Wrenched from the other side and finally got it out. Putting it back was a bitch. Took me two hours in the blazing sun.