This is the continuing saga of my wagon (108K). I have: cleaned throttle body, checked IAC, throttle switch, unplugged AMM and replugged several times (an effort to clean the contacts), replaced FPR. The car was running very good at this point but with check engine light on. After these repairs, I disconnected the battery to clear codes and check engine light. Upon restart it idled poorly, stalling several times like it was flooded. It ran fine at speed but continued to stumble and hesitate at acceleration. The symptoms gradually improved and it finely seemed to work itself out but I got a check engine light and codes suggesting it is compensating for running lean/rich. Ran great at this point. No hesitation from start, idle good and acceleration with some minor hesitation under heavy load not really effecting drivability. Yesterday I completed the installation of a tach and again disconnected the battery which of course reset the codes and computer. Same thing happened. The car idled rough upon start and stalled a couple of times. Hesitation at most but not all starts from stop. Runs fine at speed. Has only been driven a short distance, <10 miles, since this started. I suspect the computer will compensate at some point, register a CLE and the problem will work itself out but I sure would like to get at the root of the problem. Any suggestions.

Thanks
Randy

This is an update from last week. I ordered a salvaged AMM ($50) as suggested by Ryan_R. Before I installed in a cold engine, I tried starting a couple of times with the old meter. Started, stumbled and stalled, restarted stumbled when throttle advanced but did not stall. Replaced AMM. Started, no stumble or stall. Tried again, same thing but the exhaust smelled rich. Disconnected battery to reset computer. Started and everything seems right. Drives great with no hesitation on acceleration.

I have one question though. Both AMM are bosch with #016. However the "innards" appear different. Both have the four post and wire connecting them. The new one has a "y-shaped" assembly in front of the post and wire. The old one has a small flat plate turned sideways in front of the post and wire. What is the difference. The VIN number of the car indicates a 2.4 FI system. A North Carolina car from the dealer.

Thanks everyone for your help.
Randy

My guess is the Y shaped arrangement is a newer AMM. Dan

Is your AMM original? LH 2.4 is *incredibly* adaptable.

I recently solved some vacuum problems on my 1990 245 (that triggered the CEL--the main intake hose had a hole in it). I also changed the fuel pressure regulator. While the fuel sytem was open, I had disconnected the battery. After I got everything back together again, I started her up and she ran awufl rich and then stalled. I did this a few more times with the same result. I looked at everything over and over. Everything looked OK. I unplugged the AMM and then she would idle OK... with a "funny mixture" smell in the exhaust that went away when the car was warm and the O2 sensor was doing its job. I immediately got a junkyard AMM, swapped it in, and she's run fine ever since.

Turns out that LH 2.4 can compensate for a very sick AMM... so sick that my car couldn't run after the ECU's memory had been cleared.

Mixture problems at acceleration and not at cruise seem to be AMM issues.

Good luck!
-Ryan


--
Athens, Ohio -- 1990 245 M47 125k

Ryan,
Yes this is the original AMM. The injection system is LH 2.4. The symptoms that you describe sound familiar. When I restarted yesterday it ran for a short period and stalled. This was repeated a couple of times before I could get it to run. I am trying to locate a functioning used meter to test in the car before making the purchase. I have hesitated to purchase to this point because of price and the feeling that other things might be problematic, but have just about run out of options.

Thanks for your comments
Randy

Try "www.uneedapart.com"

Between selecting for proximity and price, I was able to get a used (gauranteed working) AMM on my doorstep the next day for $30.

-Ryan
--
Athens, Ohio -- 1990 245, 125k, M47, E-codes -- 1991 745, 278k (girlfriend-mobile)

You might get more feedback if you divulge the specific codes you are getting for both the FI and Ignition systems.

And you can reset both ECUs just by pulling fuse #6. No need to disconnect battery.
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.