Car struggles to make fuel pressure

Mitco39

What did you replace them with? Just more fuel hose?

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2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

Zat_Zuma

I used the specialty fuel resistant hose that Phunk uses and didn't over tighten the hose clamps. No more gunk.

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[B]2009 & 2017 370Z Touring Sport Autos SOLD

Mitco39

So first nice day here where temps were around 70F and the stupid car can not even make enough fuel pressure out of boost. It drops down to the 20s as the car starts to get going and building boost.

When you guys set your regulators do you see the fuel pressure change? When I left the house this morning with a cold car the pressure was ~60psi with the car running. Right now as it sits it barely makes 50 with the car off. Is it common for a regulator to fluctuate that badly? Regulator is warm but not hot to the touch. I redid the wiring around the relay and I can 100% confirm that the wiring is not hot, again relay is warm but I can hold it in my hand without it burning.

I also confirmed no leaks internally in the tank anymore because the car has no issues holding ~40psi when you turn the car off.

This is very frustrating. I guess its time to get a new regulator to test it out. Its the last thing left.

__________________
2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

phunk

If you have a vacuum line connected to the regulator, the pressure will be all over the place as idle vacuum can change a bit. But if its tuned with a static fuel pressure and no vacuum line, than you shouldnt see any noticeable differences in fuel pressure.

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Mitco39

No vac line is connected.

Cold start sits at ~56-58psi, when hot its about 46-48psi.

Would this be a regulator issue possibly then? Ill get another regulator and try that tomorrow hopefully.

__________________
2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

phunk

As long as your Venturi is opened up enough and not backing up your regulator, than I would say the regulator must have a problem.

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Mitco39

I modified it with the suggested drill bit size when I did the larger pump. It doesnt creep up or anything like that. Ill get my hands on another regulator today hopefully and test it.

Thanks for your help!

__________________
2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

Mitco39

Well my spare basket showed up today...

__________________
2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

Mitco39

Well I did a thing...



I ran wires all the way to the pump, not just splicing into the small ones in the bulkhead. Took a small drill bit drilled to holes for the wires and ran them up to through the bulkhead and put some silicone around them. Filled up the tank right to the brim and no leaks, ill be keeping a close eye on it for awhile but I think shes good.

First road test I had to pull 15% fuel out of my enrichment table just to get it to run properly, it was that rich.

Time will tell if this was the fix, trying not to get my hopes up but we will see once I take it out for a good cruise.

__________________
2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

Kamillio

How is the car doing now? What did you find was your problem?

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370z