Really need your expert help on Fuel pump Relay

[Art'74]

I have a '99 454/7.4 in a K5 Blazer. It has run on ether with good oil press, etc. So all the wiring to make it run for a short time is good. Now to make it where it will run more than 15 seconds, I need the following info:

I understand from searching that I need a relay for the in-tank fuel pump to work. I also understand the wiring is orange - batt pwr, tan/gray to pump, green - 12v from computer & black grd.

What I need help with is two items (actually I need a lot more help than that but that's another story )

1) Please tell me where to get the 12v from the computer? wire color/location - as much info. as you can provide.
2) Can I just hook the tan/gray to the wire going back to the pump from under the hood or do I have to run a separate wire back to the pump wiring by the tank?

Please keep it simple for a dummy!

Thanks!

 

[dyeager535]

Is this a '99 454 *Vortec* setup, or a '99 454 that's been converted to TBI, or a 454 that is now carbed?

Kind of need to know what we are dealing with wiring-wise. I assume EFI of some type as you mention the computer, but people have tried stranger...

 

[Art'74]

I always try to provide enough info but somehow fall short. My wife says that a lot too.

It is a '99 454 out of a suburban. It is the whole engine, wiring harness for the motor and computer. Nothing has been done except put it in a different vehicle ('90 K5). I have an in-tank pump (high pressure not TBI) and was mainly concerned with getting the 12V from the computer to the fuel relay. I didn't know if I used a switched 12V if that would be sufficient.

I appreciate you replying and look forward to you bestowing your wisdom on me.

 

[bigblock72]

Pin 1 on connector C4 (black connector) at PCM applies voltage to terminal 85 on relay.

Terminal 86 on relay is connected to ground.

Terminal 87 on relay is connected to battery power and protected with a 20 amp fuse.

Terminal 30 on relay is connected to fuel pump.

Hope this helps,
Chad

 

[Art'74]

I will get on that tonight. Thanks for the phone calls and the expert technical knowledge.

I know it will be correct now instead of me trying to fumble in the dark.

I can't say thanks enough.