Hi all I just installed a Holley Terminator X on my 2005 GMC Sierra 5.3 gen 3 engine. My question is where would I hook up the green fuel wire from the Holley Terminator X so that it works with the stock fueling system.

I've read that I can run the Holley fuel control wire directly to pin 86 pos on the stock fuel relay but I'm wondering what I do with the stock fuel pump control that's in the truck now. Is this reasonable?

I plan to install a new fuel pump which I have regulator and make it a return system but that's coming later for now I would just like to get the Holly running the installation manual it says the green fuel wire is optional? If this is the case I'm not sure how the Holly is controlling the fueling does anyone have any ideas. And I'm not sure if it needs to considering the returnless system is just a steady 50 psi or whatever. The truck will start but runs really bad for only about 20 seconds not long enough to go into closed loop learn I have a feeling it's fueling issue

 

Are you piggybacking off the stock ECM? If not, you might want to and look into this harness: https://currentperformance.com/shop/...ation-harness/

 

tie it to the stock fuel pump wire from the ecu. its pin 9 of the green connector at the ecu. that will retain the stock fuel pump relay and fuse.
if you want to eliminate all the stock wiring, then just tie into the wire coming off the fuse box .
https://www.lt1swap.com/pictures/03t...20Controls.gif

 

Awesome, thanks

 

I was looking at my stock ECU and it looks like there are only two giant gray connectors going to it. Not sure I'm looking in the right place is that where you intended me to tie in? I'm looking at the ECU under the hood

 

I'm looking at the stock ECU under the hood but I don't see a green connector only two giant gray ones. Just checking to see if I'm looking in the right spot.

 

I haven't looked at the instructions in a while, but is the green wire that powers the fuel pump?

If so, you want to connect that wire to the wire that powers the fuel pump on the truck. I would not hook the green wire to the PCM, you will let the smoke out of something.

I would find the wire that powers the fuel pump, the fuel pump relay would probably be the easiest, connect the green wire to the wire that goes to the fuel pump.

The Holley harness has a fuse and a relay for the fuel pump ciircuit, there's no reason to have the green wire trigger the factory relay to activate the fuel pump.

The Holley will turn the fuel pump on when you turn the key on and the Holley powers up.

 

According to that schematic, you are going to splice the green wire from the Holley into the gray wire that comes off the fuel pump relay, which should be pin 87

 

that's what I'm going to try for now right now I have the Holly management green wire Jam down into 1086 on the stock fuel relay

 

in the Holy installation manual it says that the fuel control wire coming from the Holly is optional but I'm a little confused I can't get my head around if I use the stock pump why I would need the Holly because the stock pump on a returnless system just supplies 55 lb of gas give or take so I don't know why The Hollies needed. But I'm working with that tuner remotely who's very good at what he does because it looks like my fuel pump may be kicking on and priming but shutting off for whatever reason?

 

As I asked previously, do you have your system set up to piggyback off the factory ECM? You are going to be chasing your tail if you are and it's not set up correctly. Your crank signal needs to be split in order for your factory ECM to see the engine running so the fuel pump will stay on. This is why it keeps shutting off, most likely. You probably DON'T need to use that trigger wire, but you likely DO need an integration harness, or at minimum a crank signal splitter.

 

when you remove the connectors from the ecu they have removable colored pin retainers.