I have 75 1.8L with L-jet FI. We have completed an engine rebuild and determined that it is running to lean. A:F ratio of 17. We are trying to get it in the 13 or 15 range to make it fatter. I have replaced the AFM with a NOS unit. Any suggestions?

The AFM is adjustable. It's pretty easy, the hardest part is getting the cover off. There's a great tutorial available..

Here...
http://forums.bimmerforums.com/forum/showthread.php?t=489885

Not sure what this link is for...it talks about tranny swaps for BMW's. Can you be more specific? Thanks.

Are you drinking again Joe?

Oops.

Yes.

http://www.itinerant-air-cooled.com/viewtopic.php?t=7761

Perfect. I shall read this carefully and have a go at it in the morning. I'll let you know how it turns out. Thanks.

Mucking with the air flow meter is very very very hard to un-do. I wouldn't try it as the first step.

In fact, the first step should be to find and eliminate any and all vacuum leaks. When un-metered air gets into an L-jet intake, the FI doesn't "know" about it so it cannot add fuel to go along with it. Which results in a lean mixture.

Also check the fuel pressure. Is it in spec? (I forget the spec for the 1.8s, sorry!)

--DD

Not adjustable. If it's not right, you have choices. Pump, fuel line path, regulator, vacuum supply to regulator. Of course, if the cam profile has been "Upgraded", there's always the ol' "split the case and put in a stock cam trick". As with D-jet, L-jet is intolerant of camshaft changes.

The Cap'n

I guess I'd better tell Andy (Scarlet75) he needs us to install a stock cam in his 2.2L.

Previous owner installed a 73 grind. Is it that much different than stock? We've checked for leaks and fuel pressure is in spec. Just put the engine back in car after rebuild using the 73 grind.

What RPM does your tach show when at idle?

I will never go back to stock

Its pretty easy to adjust the AFM once you open it up. You need a A/F meter to tell you the mix as you do the adjusting inside the AFM. If you are at 17 to 1, what rpm is this at?
You want to be running the test at 2500 rpms up a slight long slope so the engine is under load not coasting. Read the AF meter and then adjust the wiper like in Colin's article. Check the WOT and then set the idle mix.

With a Web 73 you will have to run 1000 rpm idle speed.

That may just be mis-adjusting things to cover up a more basic problem. I still say that there's a good chance of vacuum leaks.

--DD

Dave, he says he is running a Web73 which takes a richer mixture to run right so you have to adjust the AFR. There is no vooddo just a little work.

....Strictly voodoo, unless you" know" what you are looking for?(readings)

do you still have your decel valve hooked up? mine gave me plenty of trouble trying to get idle down and A/F ratio under control. try blocking the vac line to it if you have one and see how she goes, those are some big ol' vacuum lines and contribute a lot of air to the system.