foshdafosh

Hi there all,

Does anyone have any suggestions as to how I can sort out the fuel pressure in my new ITB build?

I can't get it over 1.2 bar or so, but can't find any leaks.
It's fitted with new Jenvey fuel rail, Deatshwerks injectors, and an AEM FPR. All joined together with Earls braided hose, attached to a Full Blown motorsports hardline adapter.
The FPR is set to full pressure.

Don't skip the obvious stuff under the assumption that I know what I'm doing. Because I don't. :-)

Thanks either way!
Pete

crxdx

Base pressure should be set with the vacuum line off the regulator. did you do it this way?

foshdafosh

Thanks for the reply.

Not sure what you mean by setting base pressure, so I'll let you know what I've done instead!

I've been turning the key to On to start the fuel pump for a moment, and reading the guage as I do. I've tried that with and without the vacuum hose attached to the FPR.
No position I put the adjuster in seems to make any difference to the reading.

There are no fuel leaks that I can see/hear/smell.

Any of that sound like I'm doing it wrong?

chris_barry

Is the fuel pressure gauge fluid filled? If it is you need at least 1/4 of the gauge with a bubble in it. if its full of fluid and gets hot the fluid expands against the fuel pressure and it will read low, sometimes very low as the glycerine they use expands alot.

Prise off the rubber cap on the back of the gauge and shake out approx 1/4 of the liquid. Push the rubber back in at it should read correctly.

foshdafosh

Thanks Chris, annoyingly there is already a bubble of about 1/4.
The guage is almost completely upside down as I assumed that made no difference. Am I right in that?

wadzii

Sounds obvious but I had a car come in with a similar issue.. had a fuel hose kinked.

foshdafosh

Hmmm. Well it's braided hose, so it's not easy to kink, but then again you can't really see the actual hose so I suppose it could have some problem I can't see.

I'll check them all over when I get home, thanks for the tip!

chris_barry

Gauge can be any orientation. Can you get the right fuel pressure when everything is cold? What is the layout of your fuel lines? ( connection schematic, ascii art will do)

Is the return line soft enough to squeeze and block with a set of pliers?

foshdafosh

The car is always cold, you could punch a hole in the garage so it's tricky to heat!

Standard Fuel Pump ==> Standard Hard Line ==> Braided Line ==> Jenvey Fuel Rail ==> AEM FPR ==> Braided Fuel Return Line ==> Standard Return Hard Line

I can probably squash the return line, or I could just replace the return with a plug or something if you think I should try cycling the pump with the return blocked?

I just had a thought, I've taken this off the car:
https://www.dropbox.com/s/j2errzx4tk...id%20Valve.pdf
All I did was block off the hardline it was attached to as I thought it was another fuel return that I didn't need.

By the way, I checked the lines and there are no kinks etc. Ta for the tip anyway!

chris_barry

Is the return line coming out of the bottom of the FPR?

Run the return into a container to make sure its gushing out.

Try blocking the return line and cycling the pump. Should stall the pump around 70psi or 4.5 bar.