Fuel Regulator - ZR-1 Net Registry Forums

ROGER E · 06-08-2007

I think my fuel regulator which is located at the rear of the plenum is bad. I removed the vacuum line to it today and forgot to put it back, then started the car and drove down the block. The car didn't run very well due to the vacuum leak, but I thought that with out the plenum vacuum the regulator should'nt let any fuel pass at all. So if this is the case... is it possible that it is not opening enough during high demand? Or is this just an open or closed type device with no actual regulation properties?

jonszr1 · 06-08-2007

no actually you can plug off the vacuum part and get 4lbs increase in pressure . its an old lt1 trick . nothing is wrong with it at all just hook it up and go . or id she running bad?

Tyler Townsley · 06-09-2007

Quote:

Originally Posted by ROGER E

I think my fuel regulator which is located at the rear of the plenum is bad. I removed the vacuum line to it today and forgot to put it back, then started the car and drove down the block. The car didn't run very well due to the vacuum leak, but I thought that with out the plenum vacuum the regulator should'nt let any fuel pass at all. So if this is the case... is it possible that it is not opening enough during high demand? Or is this just an open or closed type device with no actual regulation properties?

I believe you pulled the hose off the MAP not the fuel regulator. This is a 0-5 volt ref signal the ecm uses to calculate fuel pulsewidth. It does a real poor fuel calculation without that signal.

Tyler

ROGER E · 06-09-2007

Thanks Tyler. This vacuum line is visible from the top of the plenum and the device it connects to has fuel lines running throught it. It is black and round with a small 1/8 tube connector on the top of it. A year or so ago I did some engine work and forgot to reinstall this vacuum line then too, and the engine would not fire at all.

ROGER E · 06-09-2007

The car runs fine with it all hooked up. I'm just trying to figure out if the car should fire up at all if this device controls fuel delivery.

carter200 · 06-09-2007

Yep, that is the fuel regulator.

ROGER E · 06-09-2007

Thanks Carter. So the engine shouldn't have fired with the vacuum hose removed...right?

carter200 · 06-09-2007

Can't tell you for sure but I do know 100% that the unit is the fuel pressure regulator. Sorry I do not have an answer on the starting part

XfireZ51 · 06-09-2007

The vacuum line you pulled off actually raises FP when disconnected because the regulator vacuum port is now at 100% MAP. If anything you're running rich which shouldn't harm the motor. ECM will be pulling fuel out trying to get back to stoich.

jonszr1 · 06-09-2007

the car should start with the vacuum hose unplugged. but I dont know why yours didnt/doesnt?

06-08-2007	#1
ROGER E Join Date: Apr 2004 Location: Folsom Posts: 23	Fuel Regulator I think my fuel regulator which is located at the rear of the plenum is bad. I removed the vacuum line to it today and forgot to put it back, then started the car and drove down the block. The car didn't run very well due to the vacuum leak, but I thought that with out the plenum vacuum the regulator should'nt let any fuel pass at all. So if this is the case... is it possible that it is not opening enough during high demand? Or is this just an open or closed type device with no actual regulation properties?

06-08-2007	#2
jonszr1 Join Date: Sep 2006 Location: lone pine and mammoth lakes Posts: 1,407	Re: Fuel Regulator no actually you can plug off the vacuum part and get 4lbs increase in pressure . its an old lt1 trick . nothing is wrong with it at all just hook it up and go . or id she running bad?

06-09-2007	#4
ROGER E Join Date: Apr 2004 Location: Folsom Posts: 23	Re: Fuel Regulator Thanks Tyler. This vacuum line is visible from the top of the plenum and the device it connects to has fuel lines running throught it. It is black and round with a small 1/8 tube connector on the top of it. A year or so ago I did some engine work and forgot to reinstall this vacuum line then too, and the engine would not fire at all.

06-09-2007	#5
ROGER E Join Date: Apr 2004 Location: Folsom Posts: 23	Re: Fuel Regulator The car runs fine with it all hooked up. I'm just trying to figure out if the car should fire up at all if this device controls fuel delivery.

06-09-2007	#6
carter200 Join Date: Jun 2004 Location: Texas Posts: 2,431	Re: Fuel Regulator Yep, that is the fuel regulator. __________________ 95 ZR-1 BLK/Gry #392 LT5 Reg# 868 RIP ZR1NET Founding Mem #155

06-09-2007	#7
ROGER E Join Date: Apr 2004 Location: Folsom Posts: 23	Re: Fuel Regulator Thanks Carter. So the engine shouldn't have fired with the vacuum hose removed...right?

06-09-2007	#8
carter200 Join Date: Jun 2004 Location: Texas Posts: 2,431	Re: Fuel Regulator Can't tell you for sure but I do know 100% that the unit is the fuel pressure regulator. Sorry I do not have an answer on the starting part __________________ 95 ZR-1 BLK/Gry #392 LT5 Reg# 868 RIP ZR1NET Founding Mem #155

06-09-2007	#9
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Re: Fuel Regulator The vacuum line you pulled off actually raises FP when disconnected because the regulator vacuum port is now at 100% MAP. If anything you're running rich which shouldn't harm the motor. ECM will be pulling fuel out trying to get back to stoich.

06-09-2007	#10
jonszr1 Join Date: Sep 2006 Location: lone pine and mammoth lakes Posts: 1,407	Re: Fuel Regulator the car should start with the vacuum hose unplugged. but I dont know why yours didnt/doesnt?