custom fuel regulator

brendan · Post by **brendan** » Mon Jan 16, 2006 5:24 pm

i have just bough a custom fuel reg for my piazza, just wondering if anybody else has done this and knows what pressure to set it at. If not i am just going to play trial and error till the car seems to run good.
Cheers Brendan

Post by **wedgenut** » Mon Jan 16, 2006 9:14 pm

Probably about 35psi would be okay but someone else might have the exact values.

brendan · Post by **brendan** » Tue Jan 17, 2006 8:01 pm

fitted the fuel reg this afternoon and started the pressure at 35 psi but the car still seemed to be running out of fuel at the rail up at 5800rpm and then the car would start missing and backfiring even in the next gear if i kept it flat. even when i had the pressure at 50psi it didthe same thing so i am thinking my fuel pump might be the problem again. Might try putting my vl pump back in, my car is cursed i tell ya!

Rodeobob · Post by **Rodeobob** » Wed Jan 18, 2006 1:35 am

Might also be that your boost is too high and its going too good and the injectors are a full cycle.

Bob.

brendan · Post by **brendan** » Wed Jan 18, 2006 6:57 am

the car is only running 10 psi boost, this hole mess started after a put the three inch exhaust on the car. it was running fine before that now i have no idea what is wrong

Rodeobob · Post by **Rodeobob** » Thu Jan 19, 2006 4:18 am

Exhaust could be too big.

Bugle · Post by **Bugle** » Thu Jan 19, 2006 8:54 pm

Careful going over 35psi with those hose tails they only have a clamp on the fuel rail and rely on the barbed fitting on the injector to seal there. I've heard they can leak if you increase the pressure.

I ran a bigger turbo at 10psi with 3 inch exhaust and everything else standard and it ran fine.

Be worth putting the ECU into diagnostic mode and seeing if its reporting any stuffed sensors.

Post by **wedgenut** » Fri Jan 20, 2006 9:05 pm

Problem might not be pressure but flow, check your fuel filter, blocked filter is common cause of starvation at higher RPM, exhaust change might just be coincidence.

Tommy · Post by **Tommy** » Sat Jan 21, 2006 1:58 am

Are you retaining the Vacum Switching Valve, if not fuel pressure should be 42.6psi at Idle. If you are retaining it, pressure should be 35.6 at idle, and 42.6 if you aply battery voltage to the VSV. Inoperative VSV might acount for leanout at higher revs under load.

Tommy

brendan wrote:i have just bough a custom fuel reg for my piazza, just wondering if anybody else has done this and knows what pressure to set it at. If not i am just going to play trial and error till the car seems to run good.
Cheers Brendan

Bugle · Post by **Bugle** » Sat Jan 21, 2006 12:43 pm

My service manual says normally 28.4 psi at idle and 35.6 if you switch the VSV.

brendan · Post by **brendan** » Mon Jan 23, 2006 4:02 pm

what is a vsv

Bugle · Post by **Bugle** » Mon Jan 23, 2006 4:51 pm

Electronic valve which cuts teh vacuum to the pressure regulator

brendan · Post by **brendan** » Mon Jan 23, 2006 7:49 pm

where is it, what does look like, and how do i test it..... please
cheers Brendan

Bugle · Post by **Bugle** » Tue Jan 24, 2006 4:15 pm

It's a little black thing somewhere near the cruise control actuator.
To see if it's working hook 12v up to it with the engine running and see if it turns vacuum off. Fuel pressure at idle with the standard regulator should be at 35.6 psi with the vacuum off and 28.4psi with the vacuum on.

Should get a service manual it's worth it has all this information in it.

Tommy · Post by **Tommy** » Wed Jan 25, 2006 2:46 am

My numbers came from a Workshop Manual for a 88/89 JR, these have O-ringed injectors. Probably this is the reason for the difference in the numbers.

Tommy

custom fuel regulator

custom fuel regulator

Re: custom fuel regulator