TRUCK IS ACTING CRAZY

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

PlayingWithTBI

2022 Truck of the Year
Supporting Member
Joined
Jan 3, 2019
Messages
9,667
Reaction score
15,013
Location
Tonopah, AZ
Are they supposed to ground to the intake in some way?
The iron s/b isolated from the coil, even though it's grounded to the manifold, it just helps concentrate the magnetic field from primary to secondary windings. FWIU the primary winding is grounded through the 8 wire ICM. The secondary is grounded through the spark plug, head, and then the manifold.

You must be registered for see images attach
 

thinger2

I'm Awesome
Joined
Jul 6, 2019
Messages
1,596
Reaction score
4,031
Location
Tacoma
So it sounds like you want to avoid passing current through the head bolts. If they (heads / bolts / block) were dissimilar metals, I would buy the argument sooner. For aluminum heads... it might be an issue in the long-term.

GM for years has grounded the battery to the block, at least on the iron-head engines I've seen. The battery charging current goes from the alternator to the head, the bolts, the block, to the battery. GM evidently is OK with this.



Most people don't have the experience or the knowledge base to know better.

Some talk without thinking.



Hence the reason for a "star" ground. Eliminate the undesired paths from being in the conducting path.




Yup. That's why one should stick with the OE ground arrangement.




A "ground plane" actually has a formal definition if you happen to look.
Pre TBI systems and their ground paths have very little in common with TBI systems.
The basic idea is that all grounds need to go to a cast iron part.
If that "path" is lost trough a bad or missing ground it will instead try to ground through a weaker or "less noble" material.
Which will be any cast aluminum or pot metal.
Which is likely sitting on a gasket.
Or only has a bond through the bolts.
Which is weak already.
The least noble material will get eaten up.
This is a known thing in the boat world and a known thing in automotive design.
And is the entire basis behind aerospace engineering.
It is an actual science
Chock full of folks folks with degrees and ****.
And that is just how metals react when differing materials are not properly isolated and grounded .
Its gets into all kinds of ionic tranfer and all kinds of crazy atoms and bonding ...
 

Erik the Awful

Supporting Member
Supporting Member
Joined
Aug 9, 2019
Messages
7,822
Reaction score
16,111
Location
Choctaw, OK
It's an issue with boats and aircraft because of the humidity of their environments. It's less of a problem in vehicles because we don't often get electrolytes pooling on dissimilar metals - unless you let your coolant get acidic. I've never worried about "ground planes" and I've never had a problem with cars or equipment, but I've also spent most of my career in a very dry region.

Please expound.
A battery is two dissimilar metals with an electrolyte (acid) between them. Electrons move from the anode to the cathode, and the movement of the electrons is your "electromotive force", aka voltage. Eventually the surface metal of the anode is stripped of electrons and the battery goes dead. You can force a current backwards through the metals and acid and replace those electrons, also known as "charging" the battery. In the context above, the electrons are being circulated by the alternator, so there should be no metal losing electrons, instead they're just being circulated in a loop by the alternator. When a significant amount of electrolyte ends up on dissimilar metals in the ground loop you can have a slight increase or decrease in the voltage circulating because the metals are making a weak battery. You wouldn't see the voltage change on a gauge, but gradually the anode of the two metals erodes. If your grounds are made of the same metals or stay clean and dry, you won't have a problem with it.
 

618 Syndicate

You won't...
Supporting Member
Joined
Sep 17, 2020
Messages
6,761
Reaction score
15,892
Location
Southern Illinois
It's an issue with boats and aircraft because of the humidity of their environments. It's less of a problem in vehicles because we don't often get electrolytes pooling on dissimilar metals - unless you let your coolant get acidic. I've never worried about "ground planes" and I've never had a problem with cars or equipment, but I've also spent most of my career in a very dry region.


A battery is two dissimilar metals with an electrolyte (acid) between them. Electrons move from the anode to the cathode, and the movement of the electrons is your "electromotive force", aka voltage. Eventually the surface metal of the anode is stripped of electrons and the battery goes dead. You can force a current backwards through the metals and acid and replace those electrons, also known as "charging" the battery. In the context above, the electrons are being circulated by the alternator, so there should be no metal losing electrons, instead they're just being circulated in a loop by the alternator. When a significant amount of electrolyte ends up on dissimilar metals in the ground loop you can have a slight increase or decrease in the voltage circulating because the metals are making a weak battery. You wouldn't see the voltage change on a gauge, but gradually the anode of the two metals erodes. If your grounds are made of the same metals or stay clean and dry, you won't have a problem with it.
Great explanation. I learned some stuff.
 

0xDEADBEEF

Supporting Member
Supporting Member
Joined
May 3, 2021
Messages
2,593
Reaction score
6,454
Location
127.0.0.1
It's an issue with boats and aircraft because of the humidity of their environments. It's less of a problem in vehicles because we don't often get electrolytes pooling on dissimilar metals - unless you let your coolant get acidic. I've never worried about "ground planes" and I've never had a problem with cars or equipment, but I've also spent most of my career in a very dry region.


A battery is two dissimilar metals with an electrolyte (acid) between them. Electrons move from the anode to the cathode, and the movement of the electrons is your "electromotive force", aka voltage. Eventually the surface metal of the anode is stripped of electrons and the battery goes dead.

It's not really because it ran out of electrons. It either ran out of electrolyte (sulfuric acid) or the lead/lead oxide became sulfated (in a lead acid battery).

The electrolyte actually reacts with the metals to form new compounds with result being free electrons on one side and free H+ on the other. The electrolyte is used up in the reaction. The overall result is lead sulfate and water in a lead acid battery.

Anyway, there are still electrons present on the surface. The surface has just become lead sulfate which doesn't react with sulfuric acid.
 

JACK34

I'm Awesome
Joined
Sep 6, 2020
Messages
156
Reaction score
125
Location
Illinois
You guys went deep on this one. It's running good now and if you read my previous posts you will know what I did. I cut off my exhaust just behind the 02 sensor and it's running BETTER. Gonna have my man replace the 02 sensor and weld a short exhaust system and drop it right around the back of the cab tomorrow. Thanks for all your help.
 

JACK34

I'm Awesome
Joined
Sep 6, 2020
Messages
156
Reaction score
125
Location
Illinois
Thanks for everyones help here. Just got it back the other day from my mechanic. He put a straight pipe on it just after the 02 sensor and ran it back just behind the cab with a super 10 muffler. He also replaced the 02 sensor. Runs better than it ever has. I told him what it what was doing and what I replaced and he said the distributers on these trucks are junk and he just did three last week. Maybe I should have started there first. Sanded down the cab and front end getting it ready for some SPI Epoxy primer tomorrow. Thanks again for all your help.
 
Joined
Oct 30, 2022
Messages
38
Reaction score
54
Location
Alaska
N

Your mechanic doesnt understand obd1 gm tbi.
Which is no big surprise at all..
An anceint rather short lived tech that never got passed on because of the microfiche to early document scanning transition to document imaging storage
A lot of mid 90s tech and its documentation is lost.
There was this big rush to digitize everything back then.
And they did.
And it was all done in feeble rapidly deteriorating formats that are essentially unreadable now.
We have the disks and the drives.
We just dont have a way to read them.
I can barely figure out how my friggen phone works.
I have no idea what any of you young people are talking about when it comes to computers.
None.
But I am probably one of the last people left who can program a tape reader Fanuc controller in HPGL or DXF and Im sure as hell the last guy who can run Prippet for Strippets
Since I stole the last copy of it
And the only reason that that is worthy of note is because we have some old aircraft and they need parts.
And now everybody is ancient or dead.
I know this has nothing to do with anything but Im rolling so Im gonna tell a story anyway.
Back not so long ago, back in the mid 90s.
We were all masters of our craft.
Aerospace prototype mechanics.
A guild of talented professionals.
And we built some crazy ****.
MX missiles , Tank armor, Bullitt proof cockpits.
We flew airplanes into mountains just to see what happened to them.

We shot frozen turkeys into a running ge jet turbine

And all of that is gone.
All of that generational knowledge and skill is gone.
What a lucky man I am.
To be in the right place at the right time and be smart enough to shut up and soak it all in
Thats my rant
Just wanted to tip my hat to the pioneers. There's some of the "OBS" software in us newer Models. These forums, and quotes like this will save someone some day in a way you can't imagine. I can read your code. I have no way to feel it just the same. Thank you for an inspired morning. I'm headed out the door now with a frozen turkey, ironically.... to go to my grandmothers. I must ignore any turbines.
 
Top