Gents,

Good evening.

i am a complete noob with the world of LS but have completed my LM7 swap into my 66 C10 after a few years of stop start action.

what have i got and what’s the issue?

Stock computer with a Speartech tune removing the Vats, current performance harness. Painless fuel relay and a Walbro 450 pump.

Engine would start and run with no issues initially.

It then became harder to start feeling like it was firing on 6 before clearing up to a steady idle.

Now it wont start. No fuel pressure - was a steady 60psi previously and the pump doesn’t run.

Changed the painless relay, had a spare one, still no pump.

Jumped the 85 86 terminals and pump runs.

With the pump running tried to start truck. Nonstart.

Checked feed from trigger wire. Voltage but not12v.

Question. Should the truck start with the painless relay removed and jumped or does it need the trigger wire to ‘see’ the pump is running?

what voltage should be seen at the trigger wire?

Seems like it should be a simple issue but after numerous searches not found a simple answer!

Any Advice greatly received and appreciated.

Thanks.

Paul.

 

I'd be checking grounds first. Unless you're running boost that's much more Fuel Pump than needed for a 5.3l.

 

Thanks for the reply Merv.

Building once so have specced everything for 600hp.

I also think it is an earth issue, have just purchased a pack of ground straps and am going to earth the cab, chassis and ECU and start there.

Will report back.

Paul

 

Good one Paul. gotta make sure grounds is sorted.