Fuel Pressure Regulator compatability

[siteunseen]

Will this work on my '77 if I need one? "These MSD boost adjustable regulators are designed for turbo or supercharged engines. As boost pressure increases, more fuel is required by the engine. These regulators feature a boost reference circuit that adds more fuel in relation to boost pressure." Seems like boost would be the opposite of vacuum. I have a stock motor. What do you all think?

Edited September 8, 2011 by siteunseen

[cygnusx1]

I would try to get a factory spec. regulator to be sure the fuel mixture curve does not change too much from the original intention. Rockauto.com has them. The turbo regulators usually have a 1:1 ratio against boost. I am not sure what their vacuum curve looks like. Most adj. regulators can adjust the base pressure which alters the entire fuel curve linearly. If you are running boost and want to tweak the actual fuel curve, look at a Begi Regulator with adjustable gain and onset.

Edited September 8, 2011 by cygnusx1

[siteunseen]

So does this mean the same thing "The B.E.G.I. regulators are designed specifically to add fuel to EFI engines modified with turbos, superchargers, and normally aspirated. This is accomplished by using the manifold vac/pressure to drive the fuel pressure up as the boost rises, or with the N/A engines, as the vacuum goes toward atmospheric"?

[Zed Head]

The B.E.G.I regulators allow the addition of "extra" fuel, by increasing fuel pressure at a greater then 1:1 ratio under boost. Here's a link, I can't find what B.E.G.I. stands for but I think the B.E. is Bell Engineering - http://www.bellengineering.net/PDF/FMU%20Instructions.pdf Apparently the one referred to in the link is used along with the stock regulator.

Either way, you don't need a boost referenced or rising rate regulator with your NA engine. But you really should measure your pressure under load as recommended in your other thread. The more you know, the less "extra" money you'll spend.

If you do decide to go with a new regulator though, I would avoid the Aeromotive brand. No offense to FastWoman (she mentioned the brand in the other thread), but I have one and although it is well-made and works great while the engine is running, it has a basic design flaw which lets the pressure leak out rapidly when the pump is turned off. If I don't prime the rail before hitting Start, the engine will crank for a long time before starting.

It's a good anti-theft feature and might be indirectly helping the "hot-start" issue (with fresh cold gasoline) but it's kind of tiresome to wait for the rail to pressurize after every stop.

[siteunseen]

Just got through looping the neighborhood (cops probably soon to come) about 4 times. with the gauge on drivers windshield blade. start up 24psi, cold. patted throttle went down to 22psi. started my 1st loop medium warmth 24psi, up a hill climbed to 28psi, back down other side dropped to 24psi. middle gauge heat range (hot) 24psi, rev up drops to 20 to 22psi. hot idle 24psi @800rpm. ran terrible. unplugged TPS, ran worse, got a little smoother after 3k rpm. plugged back up TPS. unhooked vacuum line from bottom of FPR and clamped it from intake side. 34psi and ran way better until I got caught at redlight. maintained 34psi but sputtered and fluttered until excess gas burnt off then ran like a jacked leg rabbit which was very strong and quick. when running so well psi was between 32 & 34. I'm no mechanic, more a maniac but I am pretty sure it runs better with the higher psi when vacuum to FPR is clamped off. $64k question, what is the problem? thanks for any input, I'll try anything.

[cygnusx1]

There is a procedure in the FSM for testing the fuel pressure regulator. You can get the 77 manual online. If the regulator passes the tests BUT you are getting low fuel pressure at high RPM/Loads, then I would look at your fuel supply line. i.e. Fuel pickup tube in the tank, fuel pump inlet, fuel filter, fuel lines, and last but not least the fuel evap control system, which could cause pressure/vacuum to build up in your fuel tank.

Besides all that, check all the basics first, then move on to the EFI checklist stuff in the FSM.

Often, one can focus on one component only, and miss the actual problem.

Edited September 8, 2011 by cygnusx1

[siteunseen]

Spoken like a true Philosopher. I've had that problem my whole life, I get something in my head and start obsessing on that one thing. Thank you Mr. Putnam for reminding me to think of all the small things that make up the big picture. I've been couped up this past week from all the rain we've had and gone crazy thinking about that FPR. I apologize to all for being kind of lazy and hoping for a quick answer for my low psi. I've downloaded FSM and will try to figure it out.

[ZCurves]

Don't forget about the Fuel Injection Bible! You can download a copy of it from the downloads section. It covers all of the EFI components and has troubleshooting too.

[cygnusx1]

Spoken like a true Philosopher. I've had that problem my whole life, I get something in my head and start obsessing on that one thing. Thank you Mr. Putnam for reminding me to think of all the small things that make up the big picture. I've been couped up this past week from all the rain we've had and gone crazy thinking about that FPR. I apologize to all for being kind of lazy and hoping for a quick answer for my low psi. I've downloaded FSM and will try to figure it out.

I only learn that it hurts, after I have hit myself with the hammer. I speak from personal mistakes. ;-) BTW, Putnam is a county in NY. I also perform grammar mistakes.

Edited September 9, 2011 by cygnusx1