camerory

iTrader: (10)

I looked over some threads about the fuel pressure regulator and I think mine has a problem.

When I accelerate or let the car sit for a while I can smell unburnt gasoline. The car will take long to start or even needs to be primed when it sits for more than 8 hours. I took off the vaccum line on the FPR and it smells like gas. Also when I took off the line with the engine on it made a hissing sound from the regulator, is this normal? I am thinking I need to get a new regulator to fix the gas smell and long starting time. The car runs fine when it is started. Any other thoughts?

Thanks,
Ryan

Formula350

iTrader: (3)

The hissing sound is more than likely the sound of vacuum from the line. Unless you covered the line with your finger after pulling it off. Otherwise there shouldn't be any fuel smell around the regulator. Generally a bad regulator will leak fuel, but I suppose that depending on how bad it is, it could leak little enough that it evaporates right away and thus only a smell is present. If the motor has it's fair share of miles, and you think that it's not been replaced ever (see if you can spot AC Delco or a GM part number on it), it wouldn't hurt to replace it.

Best way to test if it is bad is hold a torch next to it. If you car goes up in flames, you've got a bad regulator! (I'M JUST KIDDING OF COURSE!! DO NOT DO THAT heh)

camerory

iTrader: (10)

Lol, yeah, if I used a torch without the line off I could probabaly put it up in flames from the raw gas smell.

Dmaleck

iTrader: (6)

I also get a gas smell from my car when its idling or when i go WOT, but I remember a thread a while back and they said lt1's smell like that. Doesnt make sense to me but whatever. Mine starts fine though.

GMRL

Those sound like classic symptoms of a leaky FPR.

camerory

iTrader: (10)

When I first got the car about a year ago it had the gas smell but started quick and fine. But just recently it has not been starting quick. The engine/car should not have a gas smell. I am going to order a FPR this week, I will let you know if this works for me.

Dmaleck

iTrader: (6)

please do let me know if it fixes your problem!

Formula350

iTrader: (3)

Well, it could easily have gone out more than when you originally got the car. Could've been just a small rip in the diaphragm and now a larger one.

Hope the new one fixes it. If you haven't ordered it, and if the new one is around $100, might as well pick up an adjustable one

ss.slp.ls1

iTrader: (36)

For what reason exactly? Fuel delivery is computer controlled.

If the FPR doesn't solve the smell, another area to look at for a fuel smell is the EVAP and EVAP purge solenoids and the hoses that connect to them. Finally check the carbon canister in the drivers side rear wheel well.

rufrntn

you should test the fuel pressure first. if your key is in the on position and there is no or little pressure it could be the fuel pump.

that is exactly what my car was doing and i replaced the fuel filter and fpr but still same symptoms finally i replaced the fuel pump that fixed all the problems.

2XR95Z28

iTrader: (4)

i'm having the same problem right now (hard starts, cut's out above like 3500rpms, and occationally stumbles pullin away from a red light) i put a FP gauge on the schraeder valve, turn the key to the run position and the pressue with shoot up to 50psi then instantely drop to very low like 5psi max. I tried a new fuel pump and that didnt do anything, next on my list is either the FPR or injectors but i heard if it was a leaky injector is would smoke preety bad on the start up as it would be burning all the gas in the cylinders. so that leads me to either the FPR or a vacuum line or something. Could deleting the EVAP have anything to do with this cause i'm preety sure i left mine off when i did my cam swap.

ss.slp.ls1

iTrader: (36)

Easy way to tell, pull the rail up w/ injectors still attached. Turn the key to the on position but do not crank over the motor. If you see any fuel come out of any injectors, than the injector(s) are bad. Otherwise, it's likely your FPR.

Dewey

iTrader: (1)

there are a ton of different reasons for the smell of fuel, probably a loose line. the long starting makes it sound like a bad fuel pump or injector.

camerory

iTrader: (10)

Which diaphram are you talking about, in the FPR? Yes, could have been broke when I got the car. The replacement is $55 gmpartsdirect.com

camerory

iTrader: (10)

Where are the EVAP solenoids located? I actually had to replace the carbon canister because the one in the car was the the correct one and almost fell off my car, lol.

camerory

iTrader: (10)

Yeah, I was told the same think from a friend, he has a fuel pressure gauge and I will check it soon. I am going to get a new FPR because the vacuum line smells like gas. The service manual says this problem can be from: leaky injectors, bad FPR, bad ball check in fuel pump, or the flex hose in the fuel pump. After I check the pressure I should know for sure. But the only reason I am leaning toward the fuel pressure regulator is because the fuel does not cut out anywhere, it just won't hold pressure when it sits. I am thinking it is slowly leaking out of the FPR.

2XR95Z28

iTrader: (4)

I'm just confused on mine, first off like i said it hold very very little pressure once you prime the pump (shoots to 40-50psi then down to next to nothing) then it starts hard 95% of the time, and it cuts out when i try to get into it like 3500-4000rpm+. The pump is brand new. has 24# SVO's (tuned for them also). What could it be? Only things i can think of are FPR and leaky injectors? anything else i should look at?

Formula350

iTrader: (3)

So everyone has said, and maybe it's the older computers as the reason for this but, when I had my 91 (which is the same computer style as my 93) I had an AFPR on it. I could tell quite a difference between the different fuel pressures. TPiS says this about it:

"Since we introduced our Fuel Pressure Regulator in 1987, GM has adopted on the '88-'90 vehicles the fuel pressure that we have found to work well on the '85-'87's. For the '88-'90, we find that 49-52 works well. The LT1 fuel pressure is unusually high for the way the computer is calibrated. We are finding that, unless you send us your computer for reprogramming, you will be faster at 39 PSI, with a stock to bolt on modded engine.

My TPI ran really good @ 48psi, but I've always been slightly confused by their wording about the LT1s. I think they're saying that the fuel pressure @ 43psi is high for how the stock computer is programmed, but if they're saying that it's high as in NOT 43psi then I'm lost since we DO run 43psi

Anyways the computer IS set at a certain injector #, but increasing the PSI will give a small bump to your injector # rating. So the pulse width for 24# will be applied to the 25# you could make them. Which is why for someone upgrading to a really big injector needs to have it tuned.

camerory

iTrader: (10)

My factory service manual says this: Fuel pressure above 47 psi may cause a rich condition and may set DTC 45/65. Driveability conditions can include hard starting (followed by black smoke) and a strong sulphur smell in the exhaust. This test determines if the high fuel pressure is due to a restricted fuel return pipe or a faulty fuel pressure regulator.

The test basically says: fuel pressure above 47 psi, Locate and correct the restriction in the fuel return pipe to fuel tank. Or if there is no restriction in the return pipe remove the pressure regulator and check for restricted filter screen (if equipped). If that doesn't fix it says you have a faulty pressure regulator.

camerory

iTrader: (10)

Yeah, I am going to pick up a fuel pressure gauge soon. But anyway, when your car had these similar problems did it smell like a fuel leak? I am thinking the loss of pressure is due to the fuel pump ball check but the smell has to be from something else.