5.7 tbi
 

Bought a '91 suburban without engine/transmission or wiring harness for $200 body is excellent...I have a '90 suburban cracked frame going to switch everything from the '90 to the '91
I haven't actually driven it since not really sure early 2016...fuel pump I thought went out but a friend hooked the relay to the battery and it started and drove fine but obviously would drain the battery. I did replace the relay and oil pressure switch but without it being hooked to the battery with the hot wire it won't start.
I'm a total novice at wiring, any help on what is out of place would be greatly appreciated!

'90 gmc suburban 5.7 tbi/700r4 miles on engine 45k
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Re: 5.7 tbi
 

A relay is essentially a switch. If you can only get it to run by applying direct power to the "switched" terminal then whatever is telling the switch to open is where I would look. There are 4 wires on a relay... 12v power in from battery, 12v out to fuel pump, ground, and switch wire. Figure out which wire is your switch and trace it back and see if a problem shows itself. I am not familiar with the wiring for the TBI engine to give you any better advice.

Re: 5.7 tbi
 

Now, I know why the wires were wrapped in duct tape, electrical and loom...to hide this mess!

Re: 5.7 tbi
 

Fixed the engine harness today, found this when tracing the wires to the tank. Could this cause it to not start? Thanks!