brunwerk

Checked my pressure today , key on goes to 60 then needle goes down after that, loses pressure. On crank it goes to 60 then idles around 52.. give it gas and it jumps up then goes below, then back to 50ish.. this normal?

Been having all kinds of issues lately so trying to check everything out , fuel pump and relay are only a few months old.

2000 5.7 express 1500

Triaged

I'm not sure what the specs are supposed to be for your van but...
The pressure is vacuum referenced so as vacuum goes up (like at idle), fuel pressure will go down.

brunwerk

Thank you for reply.. pressure seems fine when running but when key on / engine off it rises quickly then falls to zero. When I crank it goes up to 60 quickly, then runs around 53. Engine off it quickly falls to zero. I’ve been reading this is caused by check valve in pump, regulator or injectors. I have spider injector within the intake and regulator is a part of that assembly. Might try to crimp the return line and see if it holds pressure but not loving the idea of taking intake apart for something that’s not causing me trouble. Starts fine and runs fine now thank goodness

Did check my 2002 Yukon with the 5.3 and it does hold pressure on key off

my short and long fuel trims are within spec, seems to be +\_~ 3% in both banks

would there be any reason for the fuel pump not to have a check valve?

Triaged

My Hayne's manual says 60-66 psi engine running at idle speed for 4.3L, 5.0L, and 5.7L.