Important Wiring Question

[Nick88]

On my 1988 k5 Blazer 350 tbi i want to work on the esc to narrow down a timing issue, I want to rewire the ground of esc to manifold and run a new wire to the knock sensor. I have a red wire, blue wire, black/red, and black wire running to the esc. Which wire is for what? Any help is appreciated.

 

[Nick88]

Also is it a bad idea to run a new ground to the manifold??

 

[Nick88]

the bolt on the manifold to the right of harness next to the tbi in the picture is where I want to ground it. The esc wires are coming out of the harness to the left and spliced up to a new connector with the white wires in top left.

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[Caman96]

This is no disrespect to anyone on this forum, but I would look a the GM Shop Manual for verification. Free on the forum too!

88-98 Service Manuals

Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...

www.gmt400.com

 

[PlayingWithTBI]

I want to rewire the ground of esc to manifold and run a new wire to the knock sensor. I have a red wire, blue wire, black/red, and black wire running to the esc. Which wire is for what?

This is no disrespect to anyone on this forum, but I would look a the GM Shop Manual for verification. Free on the forum too!

Yep, look at the FSM for these questions. You'll find this diagram for your 88.

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Here's where you can find all of your FSMs

www.gmt400.com/threads/88-98-service-manuals.43575/

88-98 Service Manuals

Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...

www.gmt400.com

 

[Nick88]

Yep, look at the FSM for these questions. You'll find this diagram for your 88.

You must be registered for see images attach

Here's where you can find all of your FSMs

www.gmt400.com/threads/88-98-service-manuals.43575/

88-98 Service Manuals

Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...

www.gmt400.com

I was just wondering because the ESC diagram from the manual doesnt look much like the one above my valve cover, I figured out blue for ks but do you know if it would cause any issues with ecm if i run a new ground off of esc connector to manifold?

 

[PlayingWithTBI]

do you know if it would cause any issues with ecm if i run a new ground off of esc connector to manifold?

I would run it to the same bolt on the T-Stat housing where the other grounds for the ECM go. Did you check to see if your ground is bad?

 

[Caman96]

^^^Just beat me
I too would get everything as close to original as possible.

 

[Nick88]

I would run it to the same bolt on the T-Stat housing where the other grounds for the ECM go. Did you check to see if your ground is bad?

Just out of curiosity, would there be any difference grounding it by tstat housing compared to other area closer to esc? just wondering. Also the grounds are clean yes, i wire brushed the stud and nut and also replaced the eye connector. Another question is, I am going to splice the "old ground" black wire to the connector ground on the same side, then run a new wire on the other side to the new ground, should i do this? I just dont want to risk the old wire possibly also being the ground for something else and blowing it out.

 

[PlayingWithTBI]

Just out of curiosity, would there be any difference grounding it by tstat housing compared to other area closer to esc? just wondering. Also the grounds are clean yes, i wire brushed the stud and nut and also replaced the eye connector

IDK, it may work, it may not. The Knock Sensor works on resistance so, if you lose, or change it, you may have issues. There's a reason GM did things, mostly expense but it could be "cross talk" between different sensors/components. What I was asking, did you check the ground wire from the ESC to its grounding point? If it's still good, why f**k with it? If you do, try to get it as close to OE as possible.