Author Topic: 454 Engine Harness  (Read 1539 times)

Offline Woody444

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454 Engine Harness
« on: October 09, 2020, 01:05:01 PM »
Hey! I’m new to this forum and really enjoy reading all the topics and answers everyone has. I have just purchased a 1988 (squarebody) 1ton,4x4, reg cab, automatic transmission truck. The guy I bought it from said He was driving it one day and the harness started smoking under the hood. I have checked with multiple places American Auto Wire, Painless and quite a few more and cannot find anyone that carry’s a new OEM harness. Didn’t know if anyone might have any other ideas on what I should try and do? I would also like to find a wiring diagram of the engine harness if anyone had one. It is fuel injected with the 454 and the harness is still in the truck and doesn’t looked harmed but all plugs are disconnected so it’s a guessing game right now.. Thanks!!

Offline bd

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Re: 454 Engine Harness
« Reply #1 on: October 09, 2020, 02:50:41 PM »
1988 Wiring Manual - Section Page D-1

Begin by giving the fusible links connecting to the firewall junction block and the starter solenoid 3/8" B+ stud a tug to see if any stretch or separate or if any appear to have distressed insulation.  Report what you find.
« Last Edit: October 09, 2020, 02:56:19 PM by bd »
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Woody444

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Re: 454 Engine Harness
« Reply #2 on: October 15, 2020, 05:52:05 PM »
Hey, thanks for the reply. It has no slack in it.

Offline bd

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Re: 454 Engine Harness
« Reply #3 on: October 15, 2020, 06:21:02 PM »
There should be three, at minimum.  Two at the starter and one or two at the junction block.  Did you tug on all of them?  Do any appear heat stressed (e.g., split, swollen or distorted insulation)?  You should determine what the cause of failure was before replacing or repairing anything so you don't have a repeat occurance.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Woody444

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Re: 454 Engine Harness
« Reply #4 on: October 25, 2020, 04:15:19 PM »
Hey I just checked at the fuse block and it does have about an inch of play and about 3 inches at starter

Offline bd

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Re: 454 Engine Harness
« Reply #5 on: October 26, 2020, 11:16:39 AM »
The melted links need to be replaced.  Post pics.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline twebb101

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Re: 454 Engine Harness
« Reply #6 on: January 13, 2021, 10:55:55 AM »
Hey all, new the forum, so please excuse any missteps. I have an '84 C20 454 A/T Carbureted, and need a new engine harness. I can't find them anywhere online...so I'm hoping someone here can help me locate one? If not, is there a diagram of the fuse/wire block on the firewall that explains what each wire in that block goes to? Thanks in advance!