Main ground connections

[Zorba]

Looking at both the service manual, and the actual Jeep, there are two wires that ground the battery - they look like #6 or maybe even #8, but there are two of them. Ok, so one of them goes to the engine block, the other goes to the firewall. How is the frame grounded (reliably)? I'm going to put in a heavier negative harness - should I "stop off" at the frame on my way up to the engine block? Or is there a big ol bolt someplace making that un-necessary? Dumb questions I know...

 

[GEEP4ME]

I have been over almost every inch of this thing, but I know I haven't seen it all. That being said, can't remember ever seeing a chassis ground. Don't recall anything attached to the chassis that would need a ground. I think the fuel pump....well.....can't remember on it, where it gets its ground from. Everything else that comes to mind is body grounded or engine grounded.

 

[Zorba]

I have been over almost every inch of this thing, but I know I haven't seen it all. That being said, can't remember ever seeing a chassis ground. Don't recall anything attached to the chassis that would need a ground. I think the fuel pump....well.....can't remember on it, where it gets its ground from. Everything else that comes to mind is body grounded or engine grounded.

I know it has a ground (from testing) - but how good it may be is unknown.

 

[Ephry73]

In years past it was always recommended for us "tuners" to add three more ground wired connections to the Audi/VW block from the engine bay area. One from each area of the motor mounts at 3 and 9 o'clock and another one going to the firewall at 12 o'clock. This actually made the ECU and motor seems to perform better and perhaps it was subjective, but I can honestly say whenever I did this I could feel the engine respond more smoothly, not to mention the idle steadiness and vacuum signal always improved. This was done to all MK3 and newer fuel injected cars, specially those with turbos.

A good ground is always a plus. I seem to remember a grounding strap in the TJ from the firewall area where the hood ground strap connects going to the back of the motor and bolting down at the valve cover. Don't see how it would hurt, unless you're constantly welding something to the frame and body.

 

[ColoJeep]

In this electronic filled world we live in, adding additional ground locations make sense to me!
Multiple wired connections would minimize any single point of high resistance failure.
Especially since you are changing out the cables.

A wiring rule of thumb I like to follow is what ever VW would do on a system, run as fast as you can in a 180 degree direction.

 

[Ephry73]

In this electronic filled world we live in, adding additional ground locations make sense to me!
Multiple wired connections would minimize any single point of high resistance failure.
Especially since you are changing out the cables.

A wiring rule of thumb I like to follow is what ever VW would do on a system, run as fast as you can in a 180 degree direction.

This is why we added extra grounds instead of keeping the single ground to te transmission.

 

[Cjames44]

Well if you think about it, the frame is connected to the body with bolts. So in theory, the frame is bonded to the body which is grounded.

 

[TJ4Jim]

There should be 2 grounds, a braded copper strap from the right rear head bolt stud to the firewall and a insulated strap from the dipstick bolt area to the top of the frame behind the pass shock tower.

 

[Cjames44]

On my 06 there is no strap from the dipstick area to the frame. I do have a strap from the head to the firewall, firewall to the battery, engine block to the battery. My Jeep is a 3 owner including myself, low low mileage, Jeep.

 

[TJ4Jim]

On my 06 there is no strap from the dipstick area to the frame. I do have a strap from the head to the firewall, firewall to the battery, engine block to the battery. My Jeep is a 3 owner including myself, low low mileage, Jeep.

Things changed over the years but the 06 FSM still shows it there, who knows.

 

[SSTJ]

@Zorba, what did you find on yours? I know I have the same two negative cables that you mentioned (one to engine block, one to firewall of tub). In the morning I'll see if I have the one from the dipstick to the shock tower. Mine is a 97.

 

[Zorba]

@Zorba, what did you find on yours? I know I have the same two negative cables that you mentioned (one to engine block, one to firewall of tub). In the morning I'll see if I have the one from the dipstick to the shock tower. Mine is a 97.

Nothing attached to the dipstick...

 

[SSTJ]

Nothing attached to the dipstick...

So, in your case, the only connection between the tub and the frame is the bolts attaching it? Plus the ground strap between the firewall and the engine block?

 

[Zorba]

So, in your case, the only connection between the tub and the frame is the bolts attaching it? Plus the ground strap between the firewall and the engine block?

AS I UNDERSTAND IT: There is no "official" ground connection between the frame and anything else. @mrblaine said something about the frame being only grounded through the brake lines - hopefully he will elucidate further. I added a large gauge jumper on the passenger side motor mount to act as an ADDITIONAL negative for my winch (in addition to a cable run directly to the battery).

 

[mrblaine]

AS I UNDERSTAND IT: There is no "official" ground connection between the frame and anything else. @mrblaine said something about the frame being only grounded through the brake lines - hopefully he will elucidate further. I added a large gauge jumper on the passenger side motor mount to act as an ADDITIONAL negative for my winch (in addition to a cable run directly to the battery).

We've come up with the steering column since it bolts to the tub behind the dash and then the steering shaft don't look to be specifically isolated all the way to the steering gear. Brake lines from the master to the frame at the front, and little else.

Not sure I follow the winch ground though since it is supposed to be hooked directly to the battery.

 

[SSTJ]

We've come up with the steering column since it bolts to the tub behind the dash and then the steering shaft don't look to be specifically isolated all the way to the steering gear. Brake lines from the master to the frame at the front, and little else.

Not sure I follow the winch ground though since it is supposed to be hooked directly to the battery.

Interesting, and I was just doubting this guy for saying that he had resolved his grounding problem by finding a loose ground strap under the steering column.

 

[mrblaine]

Interesting, and I was just doubting this guy for saying that he had resolved his grounding problem by finding a loose ground strap under the steering column.

There is a ground strap behind the dash that grounds the dash to the firewall. Most all items that need a ground are grounded to the tub. Almost nothing is grounded to the chassis intentionally.

 

[Gollywomper]

My 98 has a ground wire to the frame near the starter. Looks to be original, maybe.

 

[mrblaine]

My 98 has a ground wire to the frame near the starter. Looks to be original, maybe.

My 97 has one that does look OEM on the right side from the side of the block by the motor mount over to the frame. But, it is no larger than 14 gauge which is at best, Oh hey, toss a ground on that spot to confuse the fuck out of folks.

Actual intentional grounds are like the ones from the block to the firewall which are large and substantial.

 

[Gollywomper]

My 97 has one that does look OEM on the right side from the side of the block by the motor mount over to the frame. But, it is no larger than 14 gauge which is at best, Oh hey, toss a ground on that spot to confuse the fuck out of folks.

Actual intentional grounds are like the ones from the block to the firewall which are large and substantial.

Same on my 98. Found it when doing my MML.