Just had the 928 Specialist adjustable fuel pressure regulator installed along with Carl's fuel pressure gauge and the car runs worse than ever. Takes almost 30 seconds of cranking for it to catch.
No fuel pressure when engine is turned off.
On top of that a "so called direct swap repalcement "of the AFPR took the better part of 3 hours at $98.00 per hour!!!
The 928 Specialist regulator is larger than the oem unit and will not fit in the oem bracket. Also butts up against the ac lines and once in position the adjustable nut is burried in foam insulation for the ac lines and can not be adjusted.
Anyone have any clues as to why the engine needs thirty seconds of cranking to start? This can't be right. Fuel pressure is set at 30 psi.
Let's see i spent $185.00 for the RRFPR and $300.00 in labor for a engine that runs worse than before I spent the money?. WTF.

RDS

Sorry to hear about your trouble. Did you have any problems running lean before?
Why add more fuel to an NA setup? Did you change anything else?

Yes,

Motorsport x-pipe/no cats,Autothority software and 2.5 inch custom dual exhaust.

rds

Three hours seems a little rich for removing three couplings, even though they can be a pain sometimes.
How did you arrive at the 30lb figure? Its seems a little low, isn't stock around 50lbs for the 32v S? Is 30 sufficient for starting?

Maybe try cranking in more pressure to see if it affects starting for the better.

Ulimately, you need to take the car to a dyno that meters the A/F so you can properly dial in the fuel. The advantage of the RRFPR is to take out some fuel at WOT above 5K rpm. That's when the fuel really starts to dump. For the most part though, if your car is stock, its going to be tough to improve on what the stock ECU is doing during most of your driving.

With the aftermarket exhaust, you should be able to get some benefit with adjusting the fuel. Get thee to a dyno with A/F reading.

I have the same set up!
Your need to up the P! 50 psi when off.
Do it at home (free)

L-jet and LH-jet cars up through 86 should be ~36psi (2.5bar) without vacuum, which should drop to around 30psi with vacuum reference. S4+ cars should be ~55psi (3.8bar) without vacuum and 47/48psi with vacuum reference. Test and set while running.

I'd guess the system is not holding pressure in the lines while not running if it's taking an extended time to build fuel pressure to be rich enough to start. Do you smell gas while cranking?

I agree - almost sounds like the regulator is not holding pressure when the car is off - so when cold you have to wait for the lines to build up enough pressure to start. During this the injectors are squirting a rich mixture anyway so it takes that much longer to start the car.

Just a guess. I have the same gauge - right now in the garage it reads 30ish on my 81.

Could also be a bad check valve at the pump - doubt it though since you would have had the same starting problem with the stock regulator.

I also bought Dave's "adjustable fuel pressure regulator" This unit is NOT a RRFPR, it is simply an adjustable one. If you want a RRFPR you can get something like the BEGI unit that Andy supplied with his SuperModel kits.

I installed Dave's adjustable fuel pressure regulator in the position of the rear damper on my 1987 car, and swapped the damper over to the right-side fuel rail. They pretty much bolted up to the fuel rails without issue although the mounting brackets to the head did require some minor "tweaking". Of course, the other end fits to a flexable fuel line between the two, so that fitment positioning is non-critical. This provides substantial extra room for the adjustment screw.

Upon initial testing, I noticed that the system would not hold fuel pressure once the fuel pump was shut off. I called Dave, and he related that there had been some similar reports, but that the units soon began to hold pressure after they had been in service. I have only run my engine for 20-30 minutes in total since the install, and have noted that the fuel system now holds pressure for over 20 minutes before appreciable leak-down. I have also noted that the system repressurizes to full pressure within 2-3 seconds of starter cranking.

On my installation, there is adequate room for Dave's "remote adjuster" device to be installed on the diaphram adjustment screw, as well.

There are a couple different BEGI units. The one on my car is a RRFPR & a boost variable regulator all in one. This unit would not be ideal for a non-boosted car. I'm sure it would still work since it does increase pressure as vacuum decreases based on where you set it.

My AFPR also does not hold pressure. It drops to zero as soon as the motor is shut off.
No gas odor when cranking.
I presume that's why it wont start.
With the stock unit the pressure was 40 psi when the motor was off.

I need a definitve factory pressure settings so I can adjust to the reccomended 4-6 psi over per instructions.

Thanks Rich

Hit a dyno.

I posted it above. The stock Bosch regulator is 2.5bar. That is 36psi with no vacuum reference. Start the car disconnect and plug the vacuum line to the fpr and adjust to 36psi (+ 4-6 if that's what the instructions say). When you reconnect the vacuum line, it should read somewhere around 30psi (+ 4-6) at idle.

I bought an LM-1 from Innovate Motorsport to provide wideband Air/Fuel ratio information to allow me to properly tune my fuel pressure. You can log the A/F ratio while driving, thereby avoiding the need for a dyno, which are rare and expensive up here.

Unfortunately, this technology is very intreaguing and I have purchased a bunch of their peripheral engine data logging pieces, and then totally lost it and purchased a Shark Tuner from John Speake!

Matt,

its reading 30 psi now at idle?
The instructions state "4-6 psi over stock"-so should'nt that be 34-36 at idle?.


Thanks Rich