I jumped b+ to pf with key in on position and fuel pump didnt come on. Then I jumped fp to the actual battery the fuel pump came on and truck ran like a top. What could the problem be

 

SOrry truck is 1987 pickup fuel injected

 

http://www.4crawler.com/4x4/CheapTri...shtml#FuelPump

Read this link...

 

Is there power to the B+ connector? You check with a voltmeter. If there is no voltage to B+ you may have an EFI relay that is not working.

No voltmeter? There's no excuse for that: http://www.harborfreight.com/7-funct...ter-90899.html

 

I know I have asked 50 times and I have spent unknown hours looking through old posts and wire diagrams I just cant find the efi relay on my 87 pickup?

 

Try this (current) thread: https://www.yotatech.com/forums/f116...ic-box-250159/

 

YEah that is my thread but I dont see a metal canister relay in engine compartment. plus he has got a newer truck than my 87

 

Sorry, didnt see it was an 87 before I posted. I think it is behind the drivers kick panel inside the vehicle. Once you find it, everything else I posted still applies as far as the B+ wire.

 

I think you are right. Thanks for the help

 

For future reference, the FSM is a great resource for troubleshooting. Straight from the FSM:

 

Someone please correct me if I'm wrong ....

The B+ terminal in the check connector only goes hot when the key is on. So if B+ isn't hot, it would be an issue in the wiring or ignition switch.

I'll check my diagrams in a few but just wanted to put that out.

 

Thats correct, it is only hot with the key on. The reason I am suggesting the EFI relay is because that is where it gets it power from when you key on. The switch inside the EFI relay is from constant power to ignition (B+), so when you key on and that relay clicks, it switches the B+ to hot. I only know because I had the same problem, no power to B+, and when I traced the whole thing down, B+ goes into the EFI to get its switched power. Mine was bad, not making the switch to power B+. Replaced the relay, had power on B+ and started right up.
Granted, there could be many other causes, but the relay is probably the easiest thing to check to start with.

 

@replicant:
Your point is well taken; thanks.

Jumpering battery to the B+ terminal in the check connector will "back feed" voltage to any circuit that is connected to that terminal. It now looks like there's some tracing to do- find out why B+ isn't getting voltage from the ignition switch / efi relay.

(I haven't got to my diagrams yet.... )

 

BAd efi relay problem fixed thanks

 

Glad you got it fixed man.