MyE28.com

Supposedly there is a simple tweak that can be made to the pump to increase fueling. I have no idea where this might be.
I stopped at a diesel shop since I read that the early Cummins diesel used a similar pump, and they had no idea what I was talking about (and no desire to even look at the car).
Just wondering. Since it's Motronic, there also may be some electronic mods/upgrades that are possible but I have never seen any.

Do you have the electronic IP? Or mechanical?

USA spec pump (mostly mechanic with the start of injection injector).

There are basically 2 adjustments for fuel, one is the boost compensator for non-boost fuel, the other is the full load fuel screw. Boost comp is the round item on the top of the pump facing the hood. Possibly it has a cap on it, but underneath is a torx screw with a lock nut. Full load fuel adjustment is one of the screws sticking towards the firewall down under the boost comp. See the pics below. Turning the screw in adds fuel, but it also increases the idle speed so you'll need to compensate. I never got mine tuned quite right. It was jacked up so high when I got it that the idle screw wasn't even in contact with the throttle lever and it had visible smoke at idle. With any throttle it looked like I was competing in a tractor pull. I wound the screw out probably 2 full turns and was still working on getting it reasonable when the pump sprung a leak. Its currently tuned to factory spec at least until the warranty on the pump job expires. It was a little more snappy with more fuel, but its nowhere near what I'd consider fast. I think the Lincoln is a little heavier than the BMW though, so thats not helping me.

here's some info and pics

https://mopar1973man.com/cummins/articl ... pump-r299/

I think this one might be better aligned with what you want on a BMW though. I was in the process of following this when the pump went TU. I'll probably get back to it once I'm allowed to fool with it.

https://www.landroverweb.com/Pdf-files/ ... _Rev_2.pdf

If you're adding fuel, make sure the boost pressure is proper too. That was also screwed up on mine, the wastegate was partly open all the time so the turbo spooled very slow, and that adds to the redneck in a pickup truck effect. Off the top of my head I want to say the blow-off valve is set to a little over 13 psi, and the boost is supposed to max out around 12 psi. Make sure yours gets there otherwise the fuel won't do as much as it could. Boost without fuel doesn't do anything either, but if the wastegate isn't right the turbo is "lazy" and it spools up a lot slower than it should. Makes for extra-lame acceleration from stop. Making the rod shorter increases boost pressure and spool speed. Do not pinch off the wastegate though. The turbo spools quick but its not designed to run at full scream like that.

I don't think the electronic stuff is really going to affect fuel adjustments, it controls injection timing. The non-electronic pump is a mechanical advance based on engine rpm.

oh, and something I forgot, if you mess with the idle screw, you'll need to go through the high idle / cold start system and tweak that so it works right. Too much change in idle speed could get that out far enough that it never fully disengages. At that point the idle screw stops being able to adjust things. Not sure if that is covered in the BMW manual but its well covered in the Ford manual here

http://www.grandmarq.net/gadget73/Ford% ... engine.pdf

if its not been totally screwed with, you should just be able to adjust the star wheel to get whatever the proper gap is. If the linkages have been messed with, there is a procedure for putting those all back to right too, it involves a bunch of measurements and some math and a chart.