I think that I may have found the reason that my car has failed emission not once, not twice, but thrice. I actually decided to look at my guages and my fuel pressure is showing 95 psi ! Holy **** that high. I'm guessing that the cause is the fuel pressure regulator being stuck closed. Anyone know where I can get a new and/or adjustable FP regulator?

 

Is the car running when you have the high pressure or are you reading it when the engine is shut off.

 

When it's running.

 

What should the fuel pressure be anyways?

 

There's the Mazda 38 psi + 1/psi for each pound of boost rule.

My fuel system seems to beef that up a bit though. I'm not complaining now though having run rich and safe at up to 16 psi boost now a few times.

 

Ok, thanks! So my car is TERRIBLY out of whack, I'm seeing 90 psi !!!

Please help!

 

Another question, does the FD have a returnless fuels system or not?

I'm guessing that it does have a return line. If so, I'll call the dealer and see how much a fuel pressure regulator is.

 

Yeah, from what I understand you never want to be above 70 psi.

 

Yeah that's a good guess that your regulator is broken or your return line is clogged or pinched. When you completely block flow, the stock pump has a bypass on it that triggers. This happens at around 100 PSI which fits with what you're seeing.

Did you have any work done on the car recently? Perhaps a shop guy lifed the car wrong and squashed a fuel line on the underbody and it's blocking the return?

B

 

Oh yeah ... if it turns out your FPR is bad, I'd just replace it with another stock one. Your fuel pressure should be around 38 or so at 0 manifold pressure (disconnect the vacuum line or test with the engine not running).

B

 

Thanks Wargasm...I did some work on the car recently, but I jacked it up from the engine cradle. What side of the car does the return line run down?

BTW - how much is a new fuel pressure regulator?

 

Fuel lines are on the drivers side ,if you ever changed your oil or fuel filter you should know.

 

Thanks, well I just bought the car a month ago and changed the oil once. I didn't pay attention to the fuel lines when I did it.

Any other ideas?

 

toddzilla, i think i saw your name on the corral a few time lol, welcome to the FD forums. btw how's the cobra running?

 

Yup, that's me.

The cobra is running great....running low 13s on street tires and high 12s on drag radials. It is for sale though, I'm trying to cut my expenses and throw some money into the FD. That's why I bought the GT in my sig.

 

HOLY ****! The dealer wants $1014 for a fuel pressure regulator. WTF?

 

Is that parts and labor, or just the part?

 

dude just go ahead and get either the sx unit or the aeromotive unit. you can adjust it to what you want. im not sure what it should be as i need to ask that question (in relation to my mods) also. anyways, i would go ahead and get it if you are planning on beefing up your fd. i was told the stock fpr is only good up to about 15 psi. is this true?

paul

 

Where can I buy the aeromotive FPR?

 

pm me, i can get you the aeromotive or the sx regulators. Any of your local mustangs show should have aermotive products. they are one of the biggest company that supply fuel system for the Renegade class.

 

http://66.216.67.51/subcatmfgprod.asp?0=211&1=262&2=-1

 

Ok, just to summarize. It's either

1) The stock FPR is shot
2) My return line is crimped

Is that IT? Vacuum issues couldn't cause this?

 

I would get under the car, and look over all the fuel lines. They are on the driver's side, in the little protector tray under the car. If they all check out, what I would do next is to hook up your fuel pressure gauge and check the pressure with the car not running, but turned on. Take note of that pressure. Next, take off the UIM. Disconnect the return line coming off of the FPR. Put a hose on the FPR to aim the fuel that will be leaving into a bucket or something. Now turn the car on(but don't start it), and check the fuel pressure. If the pressure is the same as the first reading then it is probably your FPR. You may even see a lack of flow from the FPR. If the pressure returns to normal then you have a block/crimp somewhere in the return system. Make sure your gauge is reading right as well. I though I had fuel pressure problems before, but it turned out that my MAC gauge was reading about 10psi too high. If you need a stock FPR I have one that I'll sell for cheap.
--Danny

 

Thanks a lot for the procedure. I only have one question, what is the UIM?

 

Sorry, it's the upper intake manifold. Once it is off the fuel lines are easily accessed.
BTW: Go Disco Stu!