check engine light flickers with engine miss

[cobb535]

My check engine light flickers with a miss in the engine. This happens at idle and all the way up through acceleration. The miss goes away on harder acceleration but the light glows solid during this time. No codes are being set other than the 1222 that has been there for a while.
A little history. This is a 1989 535i. I had an occasional high speed miss that I thought would be corrected after I peplaced the crankshaft pully/harmonic balancer yesterday. I installed a unit from my donor car as the old one had a cracked bore and broken keyway. This showed up as no spark last week due to the pulley not moving with the motor. I replaced the cap and rotor before I discovered the pulley problem.
The repair was finished yesterday afternoon and at the end of an otherwise uneventful 20 minute test drive the missing started. Cruising seems Ok. this shows up at idle and acceleration. I have checked the crankshaft position sensor clerance (0.40 ) and resistence (545 ohms) with no changes when moving the wires.
Does anyone have suggestions where to look next?

[dennyg]

I had same problems with hard acceleration and almost stalling at idle light would come on. I noticed my spark plugs had a huge gap of over .040 so I put in new NKG and gapped at .032 and light now is not coming on. Idle is still rough but not almost stalling as before. I think I have to clean contacts on AFM. But rough idle seems to be a common problem on M30.....Has anyone with 535 have a smooth idle?????????????

[cobb535]

I had same problems with hard acceleration and almost stalling at idle light would come on. I noticed my spark plugs had a huge gap of over .040 so I put in new NKG and gapped at .032 and light now is not coming on. Idle is still rough but not almost stalling as before. I think I have to clean contacts on AFM. But rough idle seems to be a common problem on M30.....Has anyone with 535 have a smooth idle?????????????
Went through as manny ignition related connectors with dielectric grease that I could find. No luck. Out of desperation I replaced my ECu Motronic box with a spare I hade from a 735 of the same year. Problem went away. Reinstalled old computer and problem returned. Today I am hapilly driving with 735 brain installed and no problems!
The computers both had the same part numbers on them. Am I missing something or should this computer work fine for me?

[Dave M]

same part number, same computer, quick fix :D

[misfortune]

This sounds like my problem exactly.

How much are ECUs? Would an EAT chip have the same effect?

[misfortune]

0 261 200 150


Those the right numbers for an 89 535i ecu?

[cobb535]

0 261 200 150


Those the right numbers for an 89 535i ecu?
My 89 535i ( build date 11/88) has 0 261 200 179 both the old one and the one from a 735i that is currently working in my 535i.