P38A Wont run

oakey · Dec 30, 2018

95 4,6 auto 180k
Car hasnt run for about two weeks and when I started her today she rstarted fine but immediately died,
Very low fuel pressure at rail as fuel just ran out rather than spraying out umder pressure
Left ignition on for few minutes to let pressure build up if a slow pump but no difference.
Eventually after many attempts she started an ran fine, but then started cutting out again,
As I didnt know I had one, the fuel filter hasnt been changed for at least 120000 miles,
Could this have the crud solidified inside due to not running fpr a bit?
Nanocom showed no faults but air flow jumping all over the place.
Anyone any ideas please?
Thank you

ukadamwest · Dec 30, 2018

sounds like your initial diagnosis might be a good start

Wazzajnr · Dec 30, 2018

I think there's a pressure relief valve somewhere to stop it overpressurising, I guess that could have failed. No idea where it is on these, might be integrated in the pump but some have one on the rail itself with a return to tank

dieseldog69 · Dec 30, 2018

Can you check the fuel pressure with an analogue gauge off the fuel rail just in case the fuel pressure sensor is out of whack?

oakey · Dec 31, 2018

Didnt know there was a pressure relief valve.
I will have a look for it
Dont have a pressure gauge.
I dont suppose a tyre pressure gauge would work?
Thank you

Saint.V8 · Dec 31, 2018

Do not use a tyre pressure gauge....must be a fuel pressure gauge or similar.

The pressure regulating valve is hidden toward the back of the plenum, under the throttle assembly....small diaphragm thing with a vac hose connected thereto.

It could be your MAF failing - if the MAF is unplugged, once the rpm gets to 500 the engine will die, unless you keep the revs above this value until the engine stabilises around 650-750 rpm.

oakey · Dec 31, 2018

Thanks for that Saint
I will check tomorrow

wammers · Jan 1, 2019

oakey said:
Thanks for that Saint
I will check tomorrow

Usually if the engine will not run with MAF connected but will run with it unplugged the MAF has failed.

oakey · Jan 1, 2019

Never got the chance today so will try again tomorrow ta

P38A Wont run

oakey

Well-Known Member

ukadamwest

Well-Known Member

Wazzajnr

Well-Known Member

dieseldog69

Well-Known Member

oakey

Well-Known Member

Saint.V8

Dyed-in-the-wool 100% RR Junkie

oakey

Well-Known Member

wammers

No longer with us, RIP

oakey

Well-Known Member

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