adjustable fuel regulator questions

[doitover]

I have a 91 318is with DASC installed. The people that did the install added an adjustable fuel regulator. No idea whose. The car has been sitting for nearly 9 months while I've been fixing other stuff. It's finally back to running but I've noticed a couple of things.

The fuel pressure dropped to 30 pounds, it should be 34 or so for how they had tuned it. I could turn the pressure down with the regulator but not up. I bought a test guage and it matched the gauge they installed on the regulator, so that's good. A quick check to see if it was one of the pumps, I pinched the return line. The pressure shot to over 60 PSI before I released the return line.
They installed a series pump in their tuning process, it seems pretty capable.

Odd thing, after doing this test the regulator started working again. I was able to set the pressure back to 34 PSI. I ran it through a few on/off cycles and it seems to hold up.

I had known for a while that the rail wasn't holding pressure with the car off. I checked that also by starting the pump then releasing it while pinching the return line. It holds pressure that way.

So, I know nothing about fuel pressure regulators but it seems that this one is dead or dying. I do know one thing, they are expensive.

Anyone have an opinion on whether this is the regulator? Also, any tips for buying a replacement?

Thanks,

[P. Kennedy]

Grassroots Motorsports magazine did a series of articles on this exact upgrade starting with the June 2005 issue, I believe.

They also could not get the adj. FPR from DASC to work, so they tossed it, in favor of a really fine unit from AEM.  $200 + shipping.

I'm building this project car as well, but have a ways to go before I get to the supercharger installation.  Maybe this summer.

[1991 E30 M42]

Stock fuel pressure is supposed to be 3bar approx 43psi. I have an adjustable fpr and will try to post a few pictures when i get a chance. I am using an external adjustable Aeromotive Universal EFI bypass reg pn: 13301. I removed the stock fpr and welded a piece of metal and an 1/8th npt bung into it to mound a gauge. I then removeth the return line from the rail and fooked it up to the bottom of the Aeromotive fpr and then ran a hose from the front of the reg to the return port on the rail. So basically the fuel goes into the rail then out into the reg then back to the tank.

[doitover]

That's the car I own. My kids have made the issues I have disappear for the time being and I didn't recall them mentioning who's unit they used.

Thanks,

Grassroots Motorsports magazine did a series of articles on this exact upgrade starting with the June 2005 issue, I believe.

They also could not get the adj. FPR from DASC to work, so they tossed it, in favor of a really fine unit from AEM.  $200 + shipping.

I'm building this project car as well, but have a ways to go before I get to the supercharger installation.  Maybe this summer.

[doitover]

Quick responce from AEM, their regulators don't hold pressure with the pump off. They do hold pressure quickly after the pump is on. They have suggested either the fuel filter or a pump going bad. I'll swap the filter, it's easy and cheap.

[JP 91iS]

That's the car I own. My kids have made the issues I have disappear for the time being and I didn't recall them mentioning who's unit they used.

Thanks,

You own the same car GRM owned and did the DASC swap into? That's cool.

[doitover]

It is cool. It hasn't really been running since I bought it last year but it is still cool.

I went by at lunch to get the PN off the filter and saw that AEM is clearly displayed on the side of the regulator. This sort of thing explains why it has taken over 6 months to fix all the little stuff that was wrong with it.