3.5 Efi Flapper Fuel Pressure

[V8david]

Hi all

RRC 3.5 Efi Flapper 1989

As the title really. I've installed a fuel pressure gauge in the 9th injector hose for diagnostics.

I'm getting 28 psi at tickover, 34 psi if I pull the vacuum hose off the back of the regulator (no fuel coming from the vacuum hose on the regulator, so that seems fine).

When I switch the engine off the fuel pressure sits at 34 psi, after an hour or so it starts to drop slowly, in the early 20's after 2 hours, 0 psi the following morning.

So my question is, is that norman? What does yours do?

Reason is I can smell a faint whiff of petrol in the oil so am trying to diagnose dribbling injectors.

Is it just a case of lifting the fuel rail and injectors, pressurising the system and seeing if any of the injectors leak?

Cheers

David

[V8david]

Sorry, just read this and realised I've been asking if my fuel pressure is norman...

NORMAL is what I meant.

So.... has anyone with a flapper efi system measured their fuel pressure and what did you get?

[Hybrid_From_Hell]

That is all about right

28 is a TAD on the lowish side, but fine, the PRV works via manifold depression, so the pipe on the back moderates pressure

so yes it will vary. Putting the guage on the 9th is prop not best best is between fuel in and the rail itself.

Some PRVs hold pressure when switched off but many don't and leak down - some fast some slow

Preesure is unlikely to be the issue - get hold of some FORTE injector cleaner, run the tank to say 1 gallon and add 2 tins and go

for a blast it will clean the varnish off more than you can belive !

Hope this helps

Nige

[V8david]

That's great, thanks Nige. I'll give that a go.