Still too rich

[GripGreg]

Hi again dudes. Willl someone tell me what sensors, or whatever I need to change to make my '81 run leaner? Like, maybe, the fuel pressure regulator is getting old? Or what else besides the AFM gear needing adjustment? Does the computer get old after 250,000? I would appreciate any & ALL opinions. I keep reading about people saying their e12 passed smog with no sweat. How come?? What's the magic trick??
Thanx In Advance,,,,,Greg

[1st 5er]

I'm thinking new hoses to insure there are no air leaks, also gaskets and seals related to the intake must not leak, the coolant temp sensor, auxiliary air valve functioning properly, ignition components including timing setting in proper working order, clean functioning injectors, unobstructed air intake system, to name a few.

The coolant temp sensor sends a signal that engine is warm and requires less fuel so this would be my first place to looks for the specific rich running symptom, after that I'd suggest systematically going over each system beginning with the simplest, air intake, then to ignition, etc. and inspecting and cleaning and/or replacing components only as needed.

I think, typically the AFM wiper adjustment will eliminate rough idle, running, etc. and not cause a rich mixture, I may be wrong, but if idle is smooth and acceleration and running is smooth through all RPM bands I'd guess your AFM is doing it's job as far as signal is concerned.

Addressing the AFM door's smooth operation is another situation which a little cleaning will more than likely correct.

Hope the above helps.
It is pretty much my weekend project list though I'm starting with my AFM because of poor performance from about 1200 to 1500 RPM's I have a stumbling effect, no matter the gear.

Then next I'm going to the Aux Air Valve, that is if my hoses get here today or tomorrow.

[Mike W.]

Always check the oxygen sensor readings first. I harp, but it is such an essential tool, along with being an input. If it shows a rich reading, I'd first look at the FPR, next AFM. If it has no reading, I'd change it, the O2 sensor itself will cause it to run rich, but if it's working, it can self correct quite a bit to compensate for errors in the FPR or AFM. Unless you have lots of spares, troubleshooting is quicker and cheaper than changing parts.

[1st 5er]

Always check the oxygen sensor readings first.

Forgot the O2.

[GripGreg]

Thanx Sherman & Mike!
The 02 sensor was replaced & checked with the engine. I just checked the FPR; it's OK. All, repeat, ALL hoses are new. No Leaks. Next is the AFM.
I just found out that there's an authorized Bosch dealer in Riverside. HUMMMM.
Does anyone have their website, or phone #? I''m going online to hopefully find the address.
Please, keep you guessing coming. Thanx,,,,,Greg

[alotawatts]

Or what else besides the AFM gear needing adjustment?

Have you tried the 1/4 turn (I think) rule of thumb for the AFM mixture screw on the bottom corner ?

[1st 5er]

Here's one reference I used when I Rejuvenated my first AFM

[GripGreg]

Carl; thanx for responding! Which way should I turn the screw?
Righty tighty(close), or lefty loosey(open)?? And, what does this do? I'm game to try anything! This makes sense, I just want to make it right: or, maybe left? Thanx,,,,Greg

[alotawatts]

It' the rich/lean mixture adjustment. Clockwise/right will close. Then left/counter-clockwise to open about 1/4 turn. This has been discussed but I cannot find it searching this site. Maybe someone else can chime in here. It may be one full turn and not 1/4 I just do not remember...

[Mike W.]

Typically 2 to 3 complete open turns is close. But when I had a less than perfect FPR, I had it open much further than that, regardless, it only really affects idle mixture IF it's not running closed loop, otherwise the O2 corrects the mixture to the ideal setting.