Cascade Crew

[Raiden]

I put some 24lb injectors back in my Z becaus of fuel prices. I then pumped up my fuel psi to 52. It ran fine, but then the car would not idle. Tuns out my fuel psi was 100!!! Then I checked the vacume line and it was leaking fuel. I replaced the fuel pressure diaphram and the injectors back to the 30's. Now, my fuel pressure is still 100! No fuel is coming out of the vacume port. The car will run when I pull the vacume line off, but when I put the vacume line back on the fuel pressure regulator, the car dies??? Any ideas??????

[Twilightoptics]

Might check your gauge.

If you put the vacuum line on your pressure will go down.

Changing your fuel injector size isn't going to save milage. Just permit you to have a failure of the engine in higher RPM/Load situations.

If you're pressure really is 100psi, you've got a bad regulator or a blockage in the return line.

[Raiden]

I will disagree with the fuel injector size and gas mpg. I get way better gas mpg with my 24's! significant difference, however, that's not the issue.

The issue is my fuel pressure. I just swapped out fuel pressure regulator diaphram and my fuel pressure is 100psi. now, my little nut that allows you to increase/decrease fuel psi is completly backed out so I can run stock fuel psi. My fuel psi normally fluctuate between 40-50 with the vacume line off. Now, it's a whopping 100! The psi regulator I had that was bad was showing this psi too, but fuel was leaking out the vacume port, since I've changed the diaphram, no leak? I checked the return lines for kinks & have found nothing! I do have a FMU but all looks fine there. Couuld you refresh my memory, the fuel suppliie line is the larger one, right? Smaller = return?

Thanks for your help!!! This is so frustrating!

[Raiden]

Something interesting,

my fuel pressure with key on engine off is 40
Key on engine on = 100

Raw fuel and water are coming out my exhaust???

[Twilightoptics]

[Raiden]

Well, the new fuel pressure diaphram is leaking. I would not doubt that was the problem all along! GRRRRRRRRRR makin me mad

[91RSVert]

Sounds like you do have a plug in the line.

[Raiden]

How do you find a plug in the line?

My fuel pressure diaphram is leaking..yes, the new one

Should I use my air compressor and push some air in the lines? I will definatley purge my fuel rail once I remove it.

[Twilightoptics]

You can use compressed air. Make sure your gas cap is off. Don't blow down the supply line.

[91RSVert]

It could be plugged back in the sending unit as well.

But IMO, if you blew the old regulator, then the new one. To me that sounds like your not sending anything back to the pump, and the regulator is the "weakest point".

[Raiden]

Good point! I'll make sure to blow my return line...with the cap off! Anything else?

[Twilightoptics]

You might verify that the return line is hooked to the right hardline at the trank and not the Canister line or the burst valve line.

[blue89]

if you have 40psi off and 100psi on it sounds like your gauge is tweaked. Hook it up to someone elses car and verify that it working right. I doubt that the car will be running at 100psi though. The stock fuel pumps dead head at about 80psi with NO fuel running to the engine. So unless you have an aftermarket pump and replaced your rubber pump connection tube you won't run 100psi very long before something breaks and spews fuel everywhere.

Without changing the injector constant in your ECM you will drasticallly change the way the car runs. Check your gauge. Not to mention i doubt you can idle a car on 40's with 100psi.

[Raiden]

I'm running 30lb injectors.

I have a Walbro 255lph pump.

Gauge is working perfect. Checked it on my other car.

Tomorrow, when I get home, I will check the lines to make sure they are connected correclty, blow compressed air into the return line, check again for crimped lines. Another thing I will check is my FMU. Maybe it's clogged or not working? I'm gong to bypass the fmu if my fuel psi is 100 and go from there

Thank you all for the help!

[Raiden]

Well, here's what I found.

I bypassed my FMU and my fuel pressure was 43.5. It would idle, and run fine.

Now I have another problem.

When I go through the rpm band, I get around 4500-5K rpms and I get a backfire? I thought it was fuel pressure. I hooked up my fuel pressure gauge and the fuel pressure increased to 85 which is normal with my FMU. I changed multiple fmu ratios with no change. I changed my timing, no change.

Another strange behavior my Z is having is it idles fine. 15inches of vacume. When I put it in drive, I get an occasional surge and vacume drops to 10, then zero. I don't think it's a vacume leak as I have sprayed the crap out of my intake, vacume hoses with started fluid and no change in my idle. My idle is a steady 15 @ idle, even in drive. But it's in drive when I get the occasional surge.

HELP Please

[Raiden]

Backfire.......the rev limiter on my MSD box is not working. I did get it to run right after chasing the gremlin

[Dewey316]

Sweet, so is she running good now?

(you should come to cows!)

[Raiden]

Dewey,

I would love to, however, I have a week @ North Bend Fire Academey for Hazmat crap for work

It's always something..usually work related.