Bosch 772 manual fuel pressure regulator replacement

[dr_amx]

HI all,

I am looking for a replacement for the Bosch 772 manual fuel pressure regulator. I could go the FWD performance route of a new regulator and fuel rail but I am wondering if there is a replacement that will fit the current (OEM?) fuel rail.

https://photos.app.goo.gl/xjX1sisU4ckH2JDs6

Thanks,
Ben

[4 l-bodies]

Hi Ben,
I'm close to you in Bloomington. What is your vehicle or application? 772 Bosch regulator? Is that the part # on the regulator? Most people when using an adjustable fuel pressure regulator on a stock fuel rail, use the Accufab regulator. It is pretty much a bolt in, but you need to shim it with a couple washers or you'll booger up the bung on the fuel rail. You can also file the points off the hex bolt, and not use the washers (that's what I do). 2nd picture is what happens when you don't use the washers, and aren't paying attention! It's original application is for a Buick. (GN/T-type/TA/Typoon) Part # is BREG

The fitting coming out of the regulator NEEDS an o-ring to seal. The 88-89 fuel rails have a return fitting that bolts into the Accufab. If you have an earlier style you will need to come up with a proper return fitting. DON"T use a brass hose nipple pipe thread with Teflon tape wrapped around it. Fire waiting to happen! See pics for correct style fitting. PM me if you need anymore info.
Todd

[iTurbo]

The fuel return port on the stock and Accufab regulators use a 14 x 1.5 metric thread with O-ring. Like Todd said, don't use a 1/4" NPT fitting even though it *seems* like it fits OK.

[zin]

There was a Bosch adjustable regulator that used to be sold by MSD (maybe still?...), I bought one, but I've never installed it, so I don't know if it's a bolt-in or not.

My application was for an early T1, my aim was to have an adjustable reg, but still appear stock, thereby sneaking it past the "Smog Nazis" here in CA...

Does this sound like the one you mention?

Mike

[4 l-bodies]

There were others that made them over the years. I've seen one where the adjustable feature was inside of the vacuum/pressure port nipple (very stealthy). Others that had a metal plate riveted to end of regulator, and others still that used a billet cap with internal o-ring that bolted to regulator and were held in place with set screws. ATR the Buick and SVO aftermarket company had a beautiful aluminum one, but that company is long, long, gone.
Todd

[dr_amx]

Sorry All,

For some reason I did not get the notifications that there were replies here. The application is a 1991 Spirit R/T. The 772 is the only part number I can see on the top side of the regulator.

- - - Updated - - -


There were others that made them over the years. I've seen one where the adjustable feature was inside of the vacuum/pressure port nipple (very stealthy). Others that had a metal plate riveted to end of regulator, and others still that used a billet cap with internal o-ring that bolted to regulator and were held in place with set screws. ATR the Buick and SVO aftermarket company had a beautiful aluminum one, but that company is long, long, gone.
Todd

This is along the lines of what I have. The riveted on plate is leaking and I am looking to replace.

[dr_amx]

Is it possible to put a stock FPR back on the car and let the CPU handle the tune? Or am I already out of the range of a stocker at this point?

TIII
-57 trim T3/T4 Turbo from FWDperformance
-FWD Performance Stage 3 Computer (18psi)
-+40 (52 lb) injectors

I tried posting a picture link but cannot seem to get the settings right from google photos.

[4 l-bodies]

Is it possible to put a stock FPR back on the car and let the CPU handle the tune? Or am I already out of the range of a stocker at this point?

-57 trim T3/T4 Turbo from FWDperformance
-FWD Performance Stage 3 Computer
-+40 (52 lb) injectors

I tried posting a picture link but cannot seem to get the settings right from google photos.

You more than likely could put a stock FPR back on but depending on where the fuel pressure is set now, you could be right on, lean or rich. Have any idea where your static fuel pressure is set now? Stock is 52-55 PSI. BTW the Accufab regulator is rebuildable. If I were you, I'd just buy an Accufab and be done with it. Quick Google search they're around $140 shipped. They work fine.
Todd

[dr_amx]

I don't know the current fuel pressure. I will have to check. Since you guys have verified that the accufab works on a stock rail I will likely do that. Lots of little things to cleanup on this car.

Thanks,
Ben

[dr_amx]

Measured the fuel pressure last night. 42psi. The AccuFab also showed up but I still need to order some fittings. How thick do these washers need to be? With the 14mm adapter, is the o-ring near the tip or the hex? Maybe this is a good time to do all of my fuel lines.

[4 l-bodies]

I used to use 2) fairly thin washers on each stud. I then (as noted in post # 2) file the points off the hex fitting, then you don't need to use washers/spacers. More than one way to go from outlet of Accufab to 1/4" hose fitting. Pictured is AN way (3 fittings) and factories solution. The Chrysler fitting is 89-92 turbo 1 application. Part # is 4418662. The o-ring is shown on fitting in post #2.
Todd

[dr_amx]

I used to use 2) fairly thin washers on each stud. I then (as noted in post # 2) file the points off the hex fitting, then you don't need to use washers/spacers. More than one way to go from outlet of Accufab to 1/4" hose fitting. Pictured is AN way (3 fittings) and factories solution. The Chrysler fitting is 89-92 turbo 1 application. Part # is 4418662. The o-ring is shown on fitting in post #2.
Todd

Thanks!
Ben

[dr_amx]

Here is why I asked the question about the fitting and the o-ring position. http://www.fwdperformance.com/Store/Product.asp?IDCatalog=7&ProductID=859 (Name: Fuel Fittings for Universal Regulator Part Number: FWD 7-0859 Description: Two fuel fittings for use with our universal Accufab regulator) These ones that FWDP sells appear to seal on the face and not the bore like the one pictured in post 2.

[4 l-bodies]

Not really sure what to make of FWDP catalogs part #'s listed. I can see how your perplexed. Shows picture of 7-0101. That looks like 1/4" NPT to 1/4" hose fitting with no o-ring. Just coincidental that 1/4" NPT screws into 14X1.50mm thread. Seal with Teflon tape? Picture of 7-0859 shows two fittings with AN o-ring boss thread? Then in Accufab description it notes; NOTE: 2 piece intake users require a brass fitting for fuel inlet, part number FWD 5-203. Inlet? Line coming out of regulator is actually the OUTLET or return going back to tank. No picture that I found of 5-203, or is that new/old part # for 7-0101?

Look where factory return line o-ring is placed. That should tell you how factory dealt with sealing this fitting.

FYI the O-ring on factory and AN fittings uses a difficult to track down O-ring. The correct O-ring part # is Standard Motor Products (SMP) SK18. Probably not going to find that at your local hardware store.
Todd

[dr_amx]

Thanks again Todd!

Ben

[4 l-bodies]

Thanks again Todd!

Ben
Glad to help Ben. Good luck with your project.
Todd

[dr_amx]

I finally got around to changing the regulator. I set the pressure back to about 44psi without the vacuum line. I also put in a new AFR. The AFR is going down to 11-10 when in a little boost. Do I need more fuel pressure?

[EaZyE426]

I finally got around to changing the regulator. I set the pressure back to about 44psi without the vacuum line. I also put in a new AFR. The AFR is going down to 11-10 when in a little boost. Do I need more fuel pressure?

If I recall correctly, 11.5 is the safe spot, 12 works great, but not as safe. If you are dipping into the 10s, it's a bit rich. But I believe the FWD Calibrations tend to run on the rich side to prevent people from popping engines.

In theory, the FWD Stage 3 computer should be expecting 55psi base pressure, but I would hazard a guess that you don't want to turn it up if you are already running a bit rich.

When measuring AFR, are you at WOT or part throttle?

[dr_amx]

Oh, I was thinking that 14 was the safe spot. I guess I have it backwards. The Innovate AF gauge reads constantly. I was watching it as I accelerate so part throttle not WOT.

[EaZyE426]

Oh, I was thinking that 14 was the safe spot. I guess I have it backwards. The Innovate AF gauge reads constantly. I was watching it as I accelerate so part throttle not WOT.

14.5 is the perfect mix for air/fuel for fuel efficiency, but will blow your engine up at WOT. The higher the number, the more lean you are running.

Check it at WOT, as part throttle, I believe, still uses the 02 input to determine fuel amount instead of just referring to the WOT map in the computer. It may lean out to a 12:1 at WOT.

[dr_amx]

"The higher the number, the more lean you are running." That makes me feel better. Guess I need more boost, lol. Thanks!

[EaZyE426]

"The higher the number, the more lean you are running." That makes me feel better. Guess I need more boost, lol. Thanks!

Remember the FPR is rising rate, so more boost means more fuel pressure. I do not claim to be incredibly knowledgable in tuning, but I think high 10s to low 11s isnt TOO rich. Hopefully someone with more experience will chime in.

[85lebaront2]

12:1 is not lean, it is rich, 16:1 is lean.