tornado019

Ok, I installed a new adjustable fuel pressure regulator this past weekend and after all kinds of problems I seem to be down to just one, the nitrous system is not getting a bump in fuel pressure when I engage it. I disconnected the nitrous line and let it fly off into the air while pushing the throttle down full with it running. The nitrous worked, but absolutely no fuel increase.

The regulator is working great now off the bottle, about 34 psi idle and 44 under throttle, which as far as I have read is correct for 4th gens.

I know it's capable of more because It was getting almost 85 psi at first. My old stock one was working fine right before I took it off.

What's going on guys? I got that feeling it's something little and stupid and I'm just thinking too hard, but I need help now...no bottle is no fun.

jcy98maxse

iTrader: (8)

what do u mean by no fuel increase? ur FP don't go up when nitrous engages. All the AFPR does is brings the fuel pressure back down to stock pressure from an aftermarket fuel pump. Your nitrous system just pulls a certain amount of fuel from your line (amount of fuel is dependent on how many shots ur running). If you run a bigger shot, it pulls more fuel hence the need for a aftermarket fuel pump to maintain the stock fuel pressure when nitrous engages. It sounds like its working fine...

tornado019

Um...yes it does increase. It always has before on the stock regulator. I am running a 100 shot and I would see 80 psi when I hit it. Now I get no increase at all, it just sits at 44.

Its a dry shot system and it has to increase pressure.l

jcy98maxse

iTrader: (8)

I thought u were running a wet kit, sorry no experience with that but wet kit, Fp don't go up.

mtrai760

iTrader: (19)

Check to make sure nothing is clogging the line. Debris can build up in the line. Have you cleaned the screen lately? Do you have the NOS dry kit? Have you tested that blue T-fitting that sends the pressure to your FPR? Your FPR is working correctly when off nitrous? Ive seen AFPR go bad before, but it sounds like you might have something else going on. You should be able to hook it up and test it sitting still. Just make sure you have the nozzle removed and venting to atmosphere, and you should be able to test it. You can also disconnect the second solenoid so that nitrous does not flow past #1, but I would feel safer removing the nozzle as well. What is your nitrous pressure at?

tornado019

I'm using a Zex kit dry kit. I did have some gunk in the line at first but I think it's cleaned out now. Nitrous pressure was around 800 psi, but I should still see some sort of increase, always have before.

The vacuum line I am using seems to work because it does affect the fpr. If I disconnect it I get lower pressure.

mtrai760

iTrader: (19)

Hmm... Doesn't Zex have their solenoids in a control box type setup? I would investigate there. Are you sure its sending pressure to your FPR?

Jime

iTrader: (10)

When you disconnect the vacuum line the fuel pressure should go higher not lower. Its the vacuum that pulls the pressure down and the opposite for the nitrous, it puts pressure on top of the diaphram and increases pressure.

tornado019

Yeah, I think I just said it backwards. But I do know the vaccuum does have an effect. And I hit the nitrous probably 2 weeks before I did this install and the pressure was fine then, jumped right up. All I did was install the new fpr then attach the vacuum line to it, I never messed with it besides pulling it off the stock.

This car is starting to **** me off. Now I got codes for a rear O2 sensor and 0302 code, EGR crap. Does that affect performance? This thing seems to be running like crap, especially now that the fuel is balanced out and not running 48 psi at idle like it was. I just CAN NOT get rid of this check engine light. Was IACV then knock sensor then some pressure switch i think related to the drop resistor mod now this crap. I'm about to run this car off a cliff.

tornado019

Ok, I think I figured out my problem, I'm illiterate. I had the vaccuum line for the intake going to the fpr and the fpr line going to the intake. Please try not to hurt yourselves laughing.

One thing, seems like I seen a fuel pressure chart or something posted here once for the different amounts of pressure for the shot your running. Anyone got that?

Jime

iTrader: (10)

Ok I was just going to post and tell you to check the lines and see if you do have pressure going to the fpr from the solenoid.

Here is a chart I made up,only 2 NOS jet settings on it and you should double check to make sure you have the correct pressure not all jettings seem to give the same readings.

Server should be up soon, ip changed and it takes a while for it to register.