TBI wiring issues, again...the week of bad luck... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cfan10 · 05-18-2018, 05:37 PM

Dog cracked tablet and all the downloaded wiring manuals were on it.
Phone camera not working, and not compatible to download the wiring manuals again! That means I cannot show photos of the wiring I need help with.
What I need help with I can't seem to find on google searches.

Wiring up the '91 suburban I've run into a few issues...wiring harness is from a '90 suburban doing the swap because the frame on the '90 is damaged. I've already swapped the 5.7 you/700r4 over to the '91... Help/advice is greatly appreciated! Thanks in advance for your time!

Oil pressure switch plug: what wire does the tan wire connect to, (mine is cut off)

Bulkhead connector: gray wire is cut off what looks like it was 3 wires connected using soldered metal clamp.
On google I saw a bulkhead diagram and looks to be (E7)

Alternator plug: brown wire is cut off what/where does the brown wire connect?
(2 wire alternator plug, pink/black and brown wire)

Transmission TCC plug: 2 purple wires with unknown plug, 1 purple wire is cut off. What/where does this wire connect to?

cfan10 · 05-18-2018, 05:44 PM

Wondering if the '88-'95 tbi ck series harnesses are a somewhat direct replacement for '90-'91 because all the old suburbans harnesses are always gone and the junkyard is overflowing with ck obs trucks and suvs.

redneckwheelman2 · 05-20-2018, 06:56 AM

the ck harness can be useable with alot of work, most of the engine and trans harness is the same on them just where they enter the cab is different with different bulkhead connectors. and different computers and wiring pinout. and different cab wiring
i had swapped the harness from my 92 k2500 into my 87 when i swapped the 4l80 in the first time. it was time consuming to do it. when i swapped from the tbi 350 to an 8.1 i ended up buying a new harness from howell instead of trying to rework a ls harness myself.

the tan from oil pressure should be for the oil gauge if i remember right.

alternator plug one of the wires should go to the computer i think for signal and one goes to the gauge

are the 2 purple wires for o2 sensors?

there is some great computer wiring diagrams on gearhead efi. thats where i had got like 95 % of my diagrams when i did the harness swap

cfan10 · 06-01-2018, 03:35 AM

Thanks this truck is driving me insane!

05-18-2018, 05:37 PM	#1
cfan10 Registered User Join Date: May 2011 Location: Texas Posts: 968	TBI wiring issues, again...the week of bad luck... Dog cracked tablet and all the downloaded wiring manuals were on it. Phone camera not working, and not compatible to download the wiring manuals again! That means I cannot show photos of the wiring I need help with. What I need help with I can't seem to find on google searches. Wiring up the '91 suburban I've run into a few issues...wiring harness is from a '90 suburban doing the swap because the frame on the '90 is damaged. I've already swapped the 5.7 you/700r4 over to the '91... Help/advice is greatly appreciated! Thanks in advance for your time! Oil pressure switch plug: what wire does the tan wire connect to, (mine is cut off) Bulkhead connector: gray wire is cut off what looks like it was 3 wires connected using soldered metal clamp. On google I saw a bulkhead diagram and looks to be (E7) Alternator plug: brown wire is cut off what/where does the brown wire connect? (2 wire alternator plug, pink/black and brown wire) Transmission TCC plug: 2 purple wires with unknown plug, 1 purple wire is cut off. What/where does this wire connect to? __________________ Rest In Peace:Mikhail {Mickey Rooney} Alpha 2/5/13 Omega 7/22/14 10:28AM I love you tremendously and outragiously Superpuppi Thai Ridgeback...The most intelligent dog known to me. Don't mess with my truck, my momma or my money...not necessarily in that order. © Stand for something or fall for anything. [LIST][*]'98 Bourbon St. Brawl ©2010

05-18-2018, 05:44 PM	#2
cfan10 Registered User Join Date: May 2011 Location: Texas Posts: 968	Re: TBI wiring issues, again...the week of bad luck... Wondering if the '88-'95 tbi ck series harnesses are a somewhat direct replacement for '90-'91 because all the old suburbans harnesses are always gone and the junkyard is overflowing with ck obs trucks and suvs. __________________ Rest In Peace:Mikhail {Mickey Rooney} Alpha 2/5/13 Omega 7/22/14 10:28AM I love you tremendously and outragiously Superpuppi Thai Ridgeback...The most intelligent dog known to me. Don't mess with my truck, my momma or my money...not necessarily in that order. © Stand for something or fall for anything. [LIST][*]'98 Bourbon St. Brawl ©2010

05-20-2018, 06:56 AM	#3
redneckwheelman2 Registered User Join Date: Jun 2009 Location: harris mn Posts: 126	Re: TBI wiring issues, again...the week of bad luck... the ck harness can be useable with alot of work, most of the engine and trans harness is the same on them just where they enter the cab is different with different bulkhead connectors. and different computers and wiring pinout. and different cab wiring i had swapped the harness from my 92 k2500 into my 87 when i swapped the 4l80 in the first time. it was time consuming to do it. when i swapped from the tbi 350 to an 8.1 i ended up buying a new harness from howell instead of trying to rework a ls harness myself. the tan from oil pressure should be for the oil gauge if i remember right. alternator plug one of the wires should go to the computer i think for signal and one goes to the gauge are the 2 purple wires for o2 sensors? there is some great computer wiring diagrams on gearhead efi. thats where i had got like 95 % of my diagrams when i did the harness swap __________________ 1987 v20 regular cab - work in progress swapped in a (1992 tbi 350 with vortec heads) old motor. currently has an 8.1l and 4l80 swap. flatbed bed 2 inch lift and 64 inch spring swap in the rear. 2002 chevy 2500hd extended long- blackbear tune. DD

06-01-2018, 03:35 AM	#4
cfan10 Registered User Join Date: May 2011 Location: Texas Posts: 968	Re: TBI wiring issues, again...the week of bad luck... Thanks this truck is driving me insane! __________________ Rest In Peace:Mikhail {Mickey Rooney} Alpha 2/5/13 Omega 7/22/14 10:28AM I love you tremendously and outragiously Superpuppi Thai Ridgeback...The most intelligent dog known to me. Don't mess with my truck, my momma or my money...not necessarily in that order. © Stand for something or fall for anything. [LIST][*]'98 Bourbon St. Brawl ©2010



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