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LS engine grounding

gt1guy

gt1guy

Apparently a racist
Joined
May 19, 2020
Member Number
241
Messages
3,275
Loc
New Iberia, La.
My understanding of the LS platform is that it very picky about how the grounding is done. (I'd imagine all computer controlled engines are the same)

Here's what I have:

LS3 crate/6l90, PSI stand alone harness/ fuse block and it has its own battery that's mounted in the back of my gutted JK.

Then I'm also running a Painless wiring system. Which has it's own fuse block. So the Jeep will be wired like a hotrod and also have its own battery in the back of the JK.

I also have a switch on the dash that can connect the two batteries together for running the winch.

Can I just use the frame as the ground for both systems? Any issues with doing that?

Can I use the frame as the ground for the winch? The batteries and winch are at opposite end of the jeep. I believe Max draw from the winch is 509amps.

Anything I should be mindful of to eliminate problems?
 
Twankie said:
Factory gm ground is to the block.
Have a ground from battery to block and battery to body.
Second ground from block to body if you want.
Click to expand...

Ok, straight from battery to block. No using the frame and/or body in the mix.

I've got a bunch of those fat braided wire ground straps. I designate one for block to tub.

Rangerrod said:
^^^this. Definitely bond harness to the back of the head.
Click to expand...

There are two ground wires that break out of the harness specifically to go to the heads.

I'm assuming this is what you were speaking about? If so, it appears that has been built into this PSI harness. Maybe that's a normal thing with any harness, I have no clue.




SLOWPOKE693 said:
I prefer to run the ground cable for the winch back to the battery. That eliminates any possibility of a sensor or other computer component becoming the path of least resistance back to ground and fucking shit up. But thats just me.....
Click to expand...

That makes sense.
 
These are slick to keep your battery connections clean.

www.victronenergy.com

Busbars - Victron Energy

Busbars are used for high current distribution and at the same time they provide connections for batteries and/or DC equipment. We offer a number of...
www.victronenergy.com www.victronenergy.com

Like so...
20171128_102549 (1).jpg
 
gt1guy said:
Good videos, I learned a few things I had no idea of. Need to watch a couple more times so it all sinks in.
Click to expand...
Even then, most likely you will be fine with what you have now.

More often than not ECM/PCM/ECU, whatever you call it, is the "star point" as it controls the engine via ground side, or provide B+ (typically 5V) and B- to sensors (and monitor B- as a data input from sensors).
 
my computer had a ground wire that said go directly to the battery.
i also did winch directly to battery.
engine to chassis ground strap
and a few other places i have grounds set up also..
always thought the more the better so something else does not find its own path to ground and heat it up..
 
M92PV4U said:
These are slick to keep your battery connections clean.

www.victronenergy.com

Busbars - Victron Energy

Busbars are used for high current distribution and at the same time they provide connections for batteries and/or DC equipment. We offer a number of...
www.victronenergy.com www.victronenergy.com

Like so...
20171128_102549 (1).jpg
Click to expand...

Do you run it like that, or do you install the cover for the positive bus? After watching a few people not put boots on connectors and rollover or various trail accidents have dead shorts I'm a little more cautious.
 
Thefishguy77 said:
Thread derail derail. What does everyone like for an aux fuse block?
Click to expand...

I've got two of the Eaton-Bussman sealed fuse boxes. One came with the Chassis wiring kit from Painless and I bought another one to transfer all the PSI harness connections/fuses over to. The second part makes me a little nervous cause when it comes to electrical, I do know what I don't know, which is everything.
 
How far away from the ECU do the ignition coils need to be?

My ECU is mounted inside the tub on the back side of the firewall extension.

Basically inside the bead rolled rectangle on the left side of it.

DSC00396.JPG



And I'd like to mount the coils just under the lip where the new firewall meats the old at the top.


DSC00364.JPG




The two locations are roughly 15"-18" apart.

Do I need to worry?
 
Last edited:
Put the coils on the valve cover, like the factory intended.
 
chaplinfj60 said:
and a few other places i have grounds set up also..
always thought the more the better so something else does not find its own path to ground and heat it up..
Click to expand...
Not how it works
Put one and size it correctly.
 
Bebop said:
Put the coils on the valve cover, like the factory intended.
Click to expand...
No can do anymore. The air intake tube runs over the valve cover.

Even if they were on the valve covers, the rear coil on each side would actually be closer to the ECU than where I'm wanting to put them. So my question would still remain.
 
GM ECU doesn't care. Put them wherever.
 
My square body chevys use this firewall battery cable buss location.

The CUCV factory battery and brackets are obnoxious but a nice group 31 and proper mod on a gm battery bracket fixes that issue.

Sorry for blurry pics, was on steelsoldiers.com and I wasnt logged in was quicker than going to take pic of 85/K30.

Originally the buss bars both positive and negative had screw on insulated covers but these dont last long in the civilian world.

20230811_095541.jpg
 
Last edited:
PAE said:
My square body chevys use this firewall battery cable buss location.

The CUCV factory battery and brackets are obnoxious but a nice group 31 and proper mod on a gm battery bracket fixes that issue.

20230811_095541.jpg
Click to expand...

For some reason having black and red wires connected together just seems like a bad idea. How can you trust what any other wire actually is at that point?

If the only thing I have to take fuzzy blurry pictures of is the paint job, I'll be happy.:flipoff2:
 
Was a stolen pic from steelsoldiers, my junction block has all black on bottom and red or a black wire wrapped first 6 inches with red electrical tape to identify it as + on positive top section.

I neglected to mention that its pretty obvious as the positive cables lugs are 5/16 hole and the negative are 3/8 hole lugs or its opposite.
 
Last edited:
gt1guy said:
How far away from the ECU do the ignition coils need to be?

My ECU is mounted inside the tube on the back side of the firewall extension.

Basically inside the bead rolled rectangle on the left side of it.

DSC00396.JPG



And I'd like to mount the coils just under the lip where the new firewall meats the old at the top.


DSC00364.JPG




The two locations are roughly 15"-18" apart.

Do I need to worry?
Click to expand...
Our teams Ultra 4 car is rear engine. Our coils are mounted up behind the driver and passenger helmets, plug wires over 2 feet long. is this right, meh, seems to be working just fine. At the last Disney, Ok race the cares suffered issues with all the high speed water crossings with the coils in the stock location. At this last Reading race, the engine took the creeks with no issues.
 
jeepkevin said:
Our teams Ultra 4 car is rear engine. Our coils are mounted up behind the driver and passenger helmets, plug wires over 2 feet long. is this right, meh, seems to be working just fine. At the last Disney, Ok race the cares suffered issues with all the high speed water crossings with the coils in the stock location. At this last Reading race, the engine took the creeks with no issues.
Click to expand...

Where is the ECU mounted compared to the coils?
 
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