Explore Swap fuel pressure question

[Tiko433]

I have a 347 stroker with Ford EFI. 97 Explorer electronics. I been having a random miss or acts like it’s not getting fuel. The scanner shows a TPS fault, I ordered a new. While trouble shooting, key on run not started the fuel pressure goes to 30 PSI , then with key left on the pressure drops to zero . Is this normal? I have never noticed this before. It has a BBK adjustable pressure regulator. It is a return system. Should the PSI hold and stay with the key on ? Maybe the regulator is bad ?

 

[EPB72]

On an OE system with initial key turned on you will a 2 second prime then pump is deactivated and fuel pressure should hold ,,test spec from memory is a max PSI drop 5-10 psi after 5min.. So no your's is not normal but I've tested hundreds that customers didn't want to correct because it possed no drivability concerns.. But one symptom could be extended cranking on start up after sitting..;;;to test regulator pressurize system pinch off return line and see if pressure drops .if so then fuel pump check valve (most common) possible injector but (way less likley)..if holds then regulator...

were you able to confirm a TPS fault? backprobe signal wire .5-.9 v closed to nearly 5.0v fully open ,,

 

[Tiko433]

Thanks … so the check valve? Is that built into the regulator? That’s a good idea on pinching the line . It through code P0 122 and PO 123, both TPS code saying circuit low and High… Im going to put a new Motorcraft one on it , I don’t trust the one that’s one there. Thanks again…. I will keep it updated