TBI Help PLease! I am at a loss. What wires needs power?

[gmcjimmy88]

need the wires (the colors) that need power for the TBI and Spark to work. I am pulling my hair out on this thing. If you have any insight please call me at 1-910-818-3929. The city Say the truck needs to run by Mon. morning or it is a $250 Fine and it gets impounded.

TBI setup is from a 1990 K5 Blazer

I am not getting fuel through the injectors. I am getting fuel to the throttle body.

Are the steering column wires needed?

What wires need what power? What color wires need switched power? I am lost with this thing. Been working on it for 7-10 days now. Need it ready for URE this weekend.

 

[bp71k5]

Usually there's an orange wire that needs constant 12V power and a (pink with black stripe) wire that needs power on start\crank\run.

There's a bunch of wiring diagrams on diy-efi.org

 

[gmcjimmy88]

Usually there's an orange wire that needs constant 12V power and a (pink with black stripe) wire that needs power on start\crank\run.

There's a bunch of wiring diagrams on diy-efi.org

It may be my work computer but none of the links on that page work. I get the http404 error

 

[Russell]

Check out www.chevythunder.com

They have complete wiring diagrams for TBI systems on there. Do you have any details on how it behaved when it quit? More than a couple times the ignition module failed on my old 89 which causes you to have spark, but not provide the timing signal to the ECM to make it pulse the injectors.

That website I provided has a step by step diagnostics section which will walk you through testing the ignition module, among other common failure points. It focuses a lot on TPI, but they share a ton of characteristics and components, so try out the TPI diagnostics too.

 

[dyeager535]

If you aren't getting fuel out of the injectors, then it may be that the injector wiring isn't powered (they are ignition 12V) or you've got something going on with the ignition. The ECM needs to see engine RPM (from the ignition components) for it to start pulsing the injectors.

Make sure you THOROUGHLY understand the wiring, and how it is interrelated, before trying to "fix" things. 99% of the time when doing an EFI swap, something isn't getting power when it should be, because it's not coming from the right source. (ignition switched, constant, etc)

 

[AZ79K5Project]

This schematic is from Chevy Thunder: http://chevythunder.com/1227747_ecm_198892.htm