While trying to solve a starting problem, I found what appears to be a grounding lug, but I am not sure. My engine install is unique in that the starter is on the right side. It is a very long expensive story, but that is where it is mounted since I have what I believe to be the first 3.4 in a 1ST Gen Trooper.

Vehicle is a '91 V6 LS. On the right side of the firewall, a large wire bundle emerges right next to the upper a/c line. The large bundle immediately splits into four smaller bundles. Three of those bundles go to connectors on the right fender well.

The fourth bundle goes to a clip down further down on the fender well and then to ? The bundle terminates four wires in a single lug-type connector with a squarish hole.

My best guess would be that it is a ground, but I have no idea where it leads. The bundle is long enough to hang down to the frame.

Anyone have an idea where the bundle should terminate?

Jim, on the 2.8 there's a machined pad on the side of the block, just forward of the knock sensor, where these wires bolt to.

On my 3.4 Donormaro motor, this area is occupied by the (now useless) crank position sensor. I just used one of the crank sensor's mounting bolts as a grounding post.

It's virtually impossible to even see where this is from the top of the eng. compt., but if you pull back the rubber inner fenderwell splash shield and peer in from the side, you can see the area underneath the pssgr's side exh. man.

Failing that, there's probably enough slack in the wires to find another, more accessible grounding point.

Can't remember fer sur what these wires are for, I recalll something about ECM grounds, but if so why would it run without these wires being grounded <img src="/forums/images/graemlins/confused.gif" alt="" />

HTH........ed

Thanks Ed. If I had made a bet with myself, I would have bet that you would respond and that you would know the answer.

I would be really surprised if it is the ECM ground because I am sure that it has been hanging loose for a while.

HEY JIM IF YOU WOULD LIKE A COPY OF THE LOCATION OF THE WIRING CONNECTORS AND THE GROUNDS I CAN COPY AND SEND THEM TO YOU I HAVE ALL OF THEM , EVEN HAVE THE PIX LOCATION BUT THEY DON,T COPY REAL GOOD , JERRY

What are all the colors of the wires?? Maybe I could look it up on my Mitchell CD-manual's electrical diagrams.

I have the starter out right now so I had to push the truck into the front of the garage. I will get the colors tomorrow when I roll the rig back a bit.

Here are the colors on those wires:

1. White with blue stripe
2. White with black stripe
3. white with green stripe
4. Brown with blue or aqua markers

Wires 1-3 all have yellow markers.

All those definitely go to the block grounding point.

I found the other ends on my wiring diagram:


1. White with blue stripe: ECM Term "A9" (Diag Enable)


2. White with black stripe: (they say black with white stripe but no matter): ECM Term "A12" (Ground)


3. white with green stripe: ECM Term "D6" (Oxygen Sens LO)


4. Brown with blue or aqua markers: ESC Module Term 2

These do look like pretty important wires, I'm surprised it would even run without them being connected. I'd hazard to say that it'll run MUCH better with them properly grounded.

BTW, re: your other post, Term "C9" of the ECM is for a Crank signal, it's a WHT-BLK wire that is supposed to go to the starter relay.

According to the diagram, for the V6, there IS a "starter relay" in the Fuse Block assy, it's got BLK-WHT, WHT, BLK-RED, and RED-BLK wires going to it.

The BLK-WHT wire off the relay ties to term "C" on the starter solenoid, if that helps.

I wonder if they got the wire colors BLK-WHT & WHT-BLK swapped in the diagram. Should be easy enough to figure that out, however.

Good Luck and let us know what happens.......ed

Well, the rig is back running. The problem this time was that the wire to the solenoid had fallen off. Unfortunately the solution was difficult as the eventual diagnosis was easy.

The starter is so buried on this rig that I had to take the starter back out to reconnect that wire. I spent over an hour trying to reconnect the wire without removing the starter. Even to attempt that I have to remove the collector pipe. Perhaps the smallest of Randy's dwarfs could have done it, but I couldn't.

The solenoid connection is simply a push-on connector.

I found a place to attach the multi-lead ground wire and that was almost as painful as the starter wire. It had to be a relatively small bolt to fit through the crimped on fitting on the wires. I finally found a correct size
bolt holding a wire loom on the bottom of the pan that locates the wires running to my favorite part of the engine - the starter. Even my Gear Wrench could barely get it off.

By the way, if my wife ever has the good sense to give up on me, I am going to find the inventor of the Gear Wrench, and marry them, regardless of their gender.

I did pull the main fuse panel loose and none of the wire patterns matched the documentation above.

We will see if the truck runs appreciably better with the ECM properly grounded.

This is strictly seat of the pants. With the grounds for the ECM properly grounded, there does seem to be a difference in performance. The engine seems to wind much quicker now, as though the ECM was not advancing the spark properly when it was not grounded.