fuel pressure?

[Neelsonwheels]

I know I am going to get some crap for this but here goes. I need to rebuild my AFPR and I need to remove it to do so. I need to discharge the pressure in the rail. I can't locate the schrader valve on the rail to let the pressure out. I know you remove the gas cap also. I think the electric fuel pressure sending unit is connected to the valve that would be used to release the pressure. It is on the drivers side front of the rail. Any thoughts on how I should go about releasing the pressure. Thanks in advance.
Neels

 

[jollygreen1964]

Re: fuel pressure?

you are correct, I would suggest waiting as long as possible to allow the pressure to bleed off, then slowly remove sending unit packed with rags. then reinstall with a T fitting so you reinstall the scrader valve.

 

[Quickstop [UK]]

Re: fuel pressure?

Disconnect the relay on the firewall by the driver fender - orange and grey wires to the fuel pump. Second from the right as you look at it from the front of the truck, just by the hinge for the hood.

Start the truck and the residual pressure will run the engine for about 10 seconds until it's gone. Easy peasy.

 

[Neelsonwheels]

Re: fuel pressure?

Thanks guys.
I'll give it a shot.

 

[Neelsonwheels]

Re: fuel pressure?

popped the gas cap and removed the sending unit. There was no pressure in the rail. The truck hasn't been started in a week. I removed the AFPR and replaced the diaphram assembley. I couldn't see a tear in the rubber but I did smell fuel in the vac line when I removed it. I will start the truck tomorow after work. I need to roll it out of the garage in case I have a fuel leek and it is raining here.I am hoping I don't have a sticking injector.

 

[Syclone22]

Re: fuel pressure?

popped the gas cap and removed the sending unit. There was no pressure in the rail. The truck hasn't been started in a week. I removed the AFPR and replaced the diaphram assembley. I couldn't see a tear in the rubber but I did smell fuel in the vac line when I removed it. I will start the truck tomorow after work. I need to roll it out of the garage in case I have a fuel leek and it is raining here.I am hoping I don't have a sticking injector.

The best way to check for a leak in the pressure regulator
is with a vacuum handpump if it leaks vacuum you have a damage
diaphram or rubber it should not have any fuel in the top of the
regulator and also check the fuel pressure at the rail when finished !! :tup:

 

[Neelsonwheels]

Re: fuel pressure?

changed out the oil and filter. Then started the truck and it started much better and seemed to run okay. I have no fuel leeks from the work I performed which is good.
My fuel pressure is 40 psi at idle and increases with throttle/boost. Is this the correct pressure or is it a little low?
I am going to drive it to work tomorow and see how it runs.

 

[Black Knight]

Re: fuel pressure?

You're good, I run 42psi, vacuum line unplugged from the regulator.

 

[alwayscode390]

Re: fuel pressure?

I think a stock truck is 42.

What is this electric fuel pressure sending unit? I have the stock fuel setup and have a gauge on the Schrader valve , will I have to get rid of that guage when I go to a walbro 255 pump in the future? ---

 

[Neelsonwheels]

Re: fuel pressure?

Its an autometer adapted to the shrader location on the rail. My truck isn't stock though.
Its .030 over Vortec heads, PT 61mm turbo, so on. I think I need a little more I will try to contact the previous owner and ask him if he remembers what it should be.

 

[Black Knight]

Re: fuel pressure?

I think a stock truck is 42.

What is this electric fuel pressure sending unit? I have the stock fuel setup and have a gauge on the Schrader valve , will I have to get rid of that guage when I go to a walbro 255 pump in the future? ---

No

 

[Black Knight]

Re: fuel pressure?

Its an autometer adapted to the shrader location on the rail. My truck isn't stock though.
Its .030 over Vortec heads, PT 61mm turbo, so on. I think I need a little more I will try to contact the previous owner and ask him if he remembers what it should be.

Do you have a wideband?

 

[alwayscode390]

Re: fuel pressure?

OOPS, I see now that its a sender to a fuel pressure gauge he has in his truck ... DUH , lol ---