Combined electrical grounds?

[obijuank5]

This is the exhaust gas temp gauge instruction sheet and it states it needs a good chassis ground, as well as a ground wire to the thermocouple amplifier chingaso.

First question, why are they separated?
Second, is the big grounding lug on the driver side a pillar considered a "good chassis ground" since the body is grounded to the frame?

Basically I want to use this main ground lug to ground everything because it is inside the cab and literally right there.

Am I allowed to do that with good results?

I am electrically unsupervised at the moment. Please advise.

 

[Wiregeek]

Proceed with caution - there may be rats remaining in that rats nest.

What you're looking at is two separate products on the same page. They are being sold together and probably work great together, but they're different parts. Each one of them needs a ground, they're not set up to share the same ground internally. Shouldn't be any heartburn at all grounding them both to that stud. I've used that stud or variants of it for a whole lot of different stuff over the years, never had problems due to it.

 

[Joel Wilson]

I am a little anal when it comes to grounds. Big wire, fine strands from battery to engine. Engine to frame. Frame to body. Both batteries too, not just the one. Put some of that spray on anti corrosive stuff on the terminals too. A good strong mechanical ground then solder the crap out of it. I had some really trick electronic gauges that I really liked, LED, set points, memory, the whole nine yards. But my alternator couldn't keep up with my overall electric load and failed causing those gauges to take a crap so please, make sure your alternator is big enough to keep up. If you could run a big ground to your A pillar, maybe like a bulkhead ground fitting or something, then I think you would be okay. Run your interior grounds to that one point, then a big fat ground straight to the battery inside the engine compartment.

maybe the extra ground is because the exhaust pipe may not be adequately grounded back to the frame or the battery? At best, you are looking at a ground path from the exhaust pipe, through the exhaust flange bolts to the manifold and then back to the block, then to the battery. I can see lots of places of high resistance there.

 

[Wiregeek]

Joel's advice is overkill but fine. Except I think you're misreading the diagram hoss - there's no ground reference at all on the sensor side of the amplifier doingus, that is a thermocouple throwing millivolts of difference due to physics stuff happening in the wires. It's self referenced and doesn't involve ground at all on that side of the amplifier.

(sayin' that brick should never be looking for ground down the thermo port, mostly).

...man, thermocouples are neat.

 

[Joel Wilson]

Joel's advice is overkill but fine. Except I think you're misreading the diagram hoss - there's no ground reference at all on the sensor side of the amplifier doingus, that is a thermocouple throwing millivolts of difference due to physics stuff happening in the wires. It's self referenced and doesn't involve ground at all on that side of the amplifier.

(sayin' that brick should never be looking for ground down the thermo port, mostly).

...man, thermocouples are neat.

I said I was anal when it came to grounds. Between Navy Electrician and Ham radio, yeah, I kinda go over kill. Sorry.

Its funny though, some people run EGT's and some don't. Our 550hp Cat at work has sequential turbos and doesn't have EGT's and it can run 40 lbs of boost under the right conditions. Things happen quick under 40 lbs of boost, sure is fun though. I personally have no problem with extra gauges, the more information you have about your rig, the better.

 

[Wiregeek]

Between Navy Electrician and Ham radio

Hooooo doggy. Next time I run into it, I'll snag you a copy of Motorola's latest R56 standard for grounding comms shelters. That book is my bible and nemesis.

 

[BoondocK5]

Painless 40140 Engine Ground Strap Kit https://a.co/d/1Usukaa

 

[Wiregeek]

My only heartburn with those is they trap filth and corrode, but hose 'em with battery terminal spray and keep an eye on 'em, they good.

 

[Joel Wilson]

Hooooo doggy. Next time I run into it, I'll snag you a copy of Motorola's latest R56 standard for grounding comms shelters. That book is my bible and nemesis.

I will keep an eye out for one. Hard to go wrong with Motorola. Thanks for the tip, man