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I'm at a complete loss at this point. I've installed a begi rrfpr on my 745i and no matter what changes I make, absolutely nothing happens.

I've installed the FPR on the return fuel line after the rail. All the instructions I've read say this is the way to do it, however I swear I've seen a few m30 cars with it installed on the feed line feeding into the stock fpr? Am I missing something here?

I've used two different fuel pressure gauges, no matter what happens the line feeding into the stock FPR is about 5psi and the return line is 36 with vacuum going to the stock fpr, 40 without. I can apply/remove vacuum to the begi, mess with both adjustments and absolutely nothing happens. I've even tried flipping the in/out around (because they weren't labeled like begi says they're supposed to be) and that made no difference.

Any ideas?

You need to place it on the line coming off the FPR at the front of the engine. The FPR functions by closing up a diaphragm and increasing pressure inside the rail. The RRFPR does the same thing but with boost pressure.
You can see my begi 2025 when i was using it, close to my oil dipstick:


My settings were needle valve full open and main screw adjustment just barely looser than 43psi when the vacuum line is off. So at atmospheric it adds just a slight bit of fuel.

Are you sure your fuel pump is strong enough?

tschultz wrote:You need to place it on the line coming off the FPR at the front of the engine. The FPR functions by closing up a diaphragm and increasing pressure inside the rail. The RRFPR does the same thing but with boost pressure.
You can see my begi 2025 when i was using it, close to my oil dipstick:


My settings were needle valve full open and main screw adjustment just barely looser than 43psi when the vacuum line is off. So at atmospheric it adds just a slight bit of fuel.

Are you sure your fuel pump is strong enough?

So you're saying I need to install it in the feed line so the RRFPR feeds the stock FPR? I thought the point of it was to build pressure in the return line so it exits through the fuel rail and into the engine instead of back to the tank. Wouldn't installing it on the feed line before the stock FPR just cause it to restrict flow?


Also, I'm running a walboro 255lph pump so I certainly hope its strong enough.

Alright so I installed it to the feed line, in order of fuel pump > begi > fuel gauge > stock FPR > rail > second fuel gauge.


Still absolutely no change with vacuum hoses on/off or playing with the hex screw. I'm pretty ****ing sure I bought a 250 dollar paper weight and I'm going to end up using this as an excuse to start buying megasquirt parts so I can just put my TCD turbo kit on.

Like tschultz says, install it on the fuel return line after the FPR. My install.

demetk wrote:Like tschultz says, install it on the fuel return line after the FPR. My install.

This.

I did end up installing it as shown above, still had no change in behavior. I figured pulling the vac line should have spiked the pressure up as I've seen all over the net.

I almost want to pull it apart and see if anything is broken inside.

If a change in a vacuum isn’t changing pressure at the rail then you have a problem with the standard FPR.

George wrote:If a change in a vacuum isn’t changing pressure at the rail then you have a problem with the standard FPR.

Its a brand new Bosch 2.5bar, when I pull the line off the stock FPR the pressure does go up. When I pull the line on the begi, nothing happens. When I pull the line on both and play with the adjustment, nothing changes.

The Begi doesn't work on vacuum, it works on pressure.

offroadkarter wrote:

George wrote:If a change in a vacuum isn’t changing pressure at the rail then you have a problem with the standard FPR.

Its a brand new Bosch 2.5bar, when I pull the line off the stock FPR the pressure does go up. When I pull the line on the begi, nothing happens. When I pull the line on both and play with the adjustment, nothing changes.

With no vacuum line connected and the engine idling, you should be able to crank in the main adjustment screw with an allen wrench. At some point you will reach a point where it starts bumping up the fuel pressure. With a turn or so past this point, you should be able to hit 65psi fuel pressure.

If that's not happening, yous diaphragm could be damaged...

The BEGI goes in the return line after the stock FPR. Won't do anything until it sees boost in the signal line. That is the whole idea.

tschultz wrote:

offroadkarter wrote:

George wrote:If a change in a vacuum isn’t changing pressure at the rail then you have a problem with the standard FPR.

Its a brand new Bosch 2.5bar, when I pull the line off the stock FPR the pressure does go up. When I pull the line on the begi, nothing happens. When I pull the line on both and play with the adjustment, nothing changes.

With no vacuum line connected and the engine idling, you should be able to crank in the main adjustment screw with an allen wrench. At some point you will reach a point where it starts bumping up the fuel pressure. With a turn or so past this point, you should be able to hit 65psi fuel pressure.

If that's not happening, yous diaphragm could be damaged...

I have read about people screwing the main screw in too far and damaging the diaphragm, I haven't threaded mine past 3-4 threads above the hex head. I've yet to see anything, hell from what I read even putting it on backwards it should spike the fuel pressure at idle.

turbodan wrote:The BEGI goes in the return line after the stock FPR. Won't do anything until it sees boost in the signal line. That is the whole idea.

Yeah I realized I was retarded and got the mix/feed lines backwards. I did install it behind the stock FPR but still noted no change. I'll mess around with it one more time this weekend and see if I can get anything to happen but I don't have high hopes at this point.

IIRC, I adjusted mine by adding pressure to the vacuum port with the help of a hand held vacuum pump and then adjusting the needle valve to get the fuel pressure I was looking for at 8 psi.

Bell has had a bunch of manufacturing issues the past few years. Most of the failures I have seen where leaking fuel but I suppose you have an out of box failure. Send it to them for repair.

Never really messed with one of these but kamotors did a rebuild on his e23 with begi, here is his video on the process.

https://www.youtube.com/watch?v=5BLOF9Dfmns