Fuel pump and TBI problems

[southernvaughan]

New guy to the forum here and not from Colorado but a K5 lover all the same. I recently put a TBI 350 and an SM465 in my 85 blazer i used the wiring harness computer and all from the donor truck i have it all hooked up and engine turns over and all but the fuel pump isnt coming on. I believe im having a grounding issue or something. Any help is appreciated.

 

[DizturbedOne]

That's really vague and hard to even start on, especially since it's a swap job and not in the original truck... What year/options is the donor truck? How about the recipient vehicle? Were both vehicles originally a manual (did the trans come from the donor also)?

To get started

Those relays aren't the best, I've seen a fair share of them go out, apply power and make sure it clicks and applies power to the other side

Alot of those TBI/TPI setups will not fire the fuel pump until it gets the OK from the oil pressure sender - Is that installed and all is well? Usually when they go out they ground out continuously and the pump won't turn OFF so you can still drive, but if it isn't even installed... Who knows what the ECM is thinking?

Those pumps are known to go out - Did you put power to it first and check it?

 

[bp71k5]

You should be able to hear the fuel pump turn on for a couple seconds after you turn the key on, but before you start the engine. If it doesn't, you can jump power to the red pigtail wire on the fuel pump relay to see if the pump comes on or not. If it doesn't come on with the jumper wire, the fuel pump isn't hooked up correctly. If it does come on, there's something wrong with the relay or the relay wiring.

 

[zombie1969]

You even sure the pump is good to begin with?Is it new?Checking for power and ground to the pump is easy enough then go from there.You could try banging on the bottom of the tank while somebody cranks it to see if it starts.I check for bad pump that way all the time.