Fuel Pressure Regulator - IMPORTANT!

BosnianLanos · Post by **BosnianLanos** » Sun Nov 25, 2007 7:03 pm

Well, after a pretty hectic first semester at school, I finally found enough time to work on my car and finish up my fuel system install. I did a Metric-AN conversion with fittings, SS braided hoses, and fittings for nitrous. Well, I managed to get everything up and running, but I think I ran into some issues with my fuel pressure regulator, the main one being that I don't think it works. Yes its just a cheap-o model from eBay, but I bought it with the intention of replacing it as soon as everything was ok.

Now, the car runs, but it threw a CEL, which begins the blink occasionally. The engine has a slight shudder (noticeably worse than normal), and the exhaust comes out in spurts, like the car has a misfire. There are no leaks, and the Air/Fuel gauge reads "optimal" when it is supposed to, and the power for the car is there, maybe even a little more power than stock. However, the FPR reads 70 psi. No matter how I turn the knob, no matter what, it reads 70 psi. I know the Lanos needs to run 40-45 psi. I took the FPR off, and found the return line to be totally dry, leading me to believe 2 things. Either that the FPR as a whole is faulty, or my placement for it is faulty. Right now I have it between the exit side of the fuel rail and the return line, in the same sequence as the stock one. Is this right? Should I have it between the filter and the inlet of the fuel rail? It seems strange, but there are some photos online showing it in that position on some cars. I do have the FPR hooked up to vacuum if anyone was wondering.

Please help guys. This is a real pain in the ass. I have to go back up to Gainesville tonight and have to leave my car at home 'till winter break before I have this figured out. Did I do something wrong or should I go online and get a new FPR.

HELP!

Damir.

BosnianLanos · Post by **BosnianLanos** » Sun Nov 25, 2007 7:22 pm

I've been searching the web for EFI FPRs. At this point cost doesn't really matter, just something that will work with the Lanos. However, almost everything I'm seeing is strange. Some with 3 ports, some with 4. I think that I only need 2 ports, one inlet, one outlet. But why do some have 2 inlet one return, or 1 inlet 2 return.

I'm so friggin' pissed.

elhombredemierda · Post by **elhombredemierda** » Sun Nov 25, 2007 10:20 pm

Damir Turina!!!! right?????

Post by **PrecisionBoost** » Sun Nov 25, 2007 10:38 pm

There are lots of different styles.... some are a single port.

Bascily with the extra ports you can usually fool around with it to adjust it so that the fuel pressure rises the way you want it to.

With vacuum it's going to be at it's lowest pressure, then if you remove the vacuum line it should jump the pressure up by about 15psi ( so 30psi with vacuum and 45 psi at atmospheric)

That would be considered a 1:1 ratio FPR (which is fairly standard)

Most have two ports one above the diaphram and one below

Usually one is "atmospheric pressure" which means you don't connect it to anything and the other is for the Vacuum line

Some will have a port for boosted cars so that the fuel pressure will rise with boost.

There are dozens of different designs.... If I were you I would avoid the cheap ebay crap like this....

http://cgi.ebay.com/ebaymotors/Fuel-Pre ... enameZWDVW

if you get a brand name one like Greddy, HKS, AEM, SARD you should be fine..... but they aren't exactly cheap.

Here is a good example of a simple AEM adjustable reg.

http://cgi.ebay.com/ebaymotors/AEM-Univ ... 0185012667

Post by **PrecisionBoost** » Sun Nov 25, 2007 10:44 pm

here is a nice SARD unit.... not too bad price wise.

http://cgi.ebay.com/ebaymotors/NEW-UNIV ... 0182821258

It's adjustable and it's a rising rate unit (in case you go turbo sometime later on this will come in handy )

If your just running naturally aspirated it will work just fine as well.

Rodd1s · Post by **Rodd1s** » Tue Nov 27, 2007 6:35 pm

sorry for jumping into this thread (seems pointless making a new one for my question)

what would be a safe maximum fuel pressure to run on the Lanos 1.3? without any modifications except cold air intake?

Post by **PrecisionBoost** » Thu Nov 29, 2007 1:50 am

Well.... I don't know if you will gain much by making it run richer... you will see it in your wallet.... as your gas mileage will definitly drop as you increase pressure.

Max pressure is 80psi.... but I personally wouldn't go that high unless you were maxing out injectors with a turbo setup

If I were you I would increase fuel pressure by no more than 5psi to 10psi (max 50 psi ) and see if the car is more responsive.

Rodd1s · Post by **Rodd1s** » Thu Nov 29, 2007 1:25 pm

thanks, a slightly quicker throttle response is all i'm after really - i just want to be able to boot it out of corners more quickly.
because ive driven an astra mk2 sri (MPFi) with increased fuel pressure and the response is far greater than standard EFi/MPFi.

Pir0 · Post by **Pir0** » Fri Nov 30, 2007 1:56 am

Most Aftermarket FPRs actually increase throttle response at low end without increasing the fuel pressure above 3 bar if I'm right. I've an FSE one on my 2.0 8v and it seems a bit gruntier at 3bar

BosnianLanos · Post by **BosnianLanos** » Thu Dec 06, 2007 5:55 pm

Thanks for all the help gentlemen. I ended up going with an Aeromotive Compact EFI Fuel Pressure Regulator, because it is from a reputable company, the reviews were good, and I can be pretty sure that it wouldn't break. Yes, it was expensive, but at this point, I couldn't care less.

http://www.jegs.com/webapp/wcs/stores/s ... 7_-1_10323

I hooked it up this morning, and all is well. This one is actually a regulator, rather than that eBay piece of crap. The car idles well, drives well, no bogging, exhaust is smooth and consistent, A/F gauge is right where it should be. All is well

I have it set at 45 psi WITH vacuum. I don't know if thats right. Like PrecisionBoost said, if I take the vacuum off, the pressure spikes up about 15 PSI.

Is it correct the way I have it set, or should I set it to 45 PSI without vacuum and allow it to drop to 30 PSI under vacuum.

Luckily this time its an easy fix.

And to Rodd1s, I really wouldn't run more than 65 PSI. Even though the max may be 80, when my car was stuck at 70, it was just straight bad for it. Misfiring, rough idle, bad exhaust flow, blinking CEL. Theres no point it in.

But I must say, I think that the new fuel system did something good to the power. Last year, when I had my bald tires, I could spin the tires shifting into second. Then, after I got my grippier Falkens, that went away, and now, with the new fuel system, It sounds more throaty, and I can chirp the tires into second again.

Good times.

Now I have to go watch for leaks.

Post by **PrecisionBoost** » Sat Dec 08, 2007 8:05 am

Looks like a decent unit..... and it has the 1:1 boost reference ( so if you turbo it the fuel pressure will increase by 1psi for every psi of boost )