1222 stomp code..found the problem

[Kibokojoe]

My son's 1991 735i e32 was running poorly and throwing a 1222 code for months now. It has finally warmed up and I decided to tackle it.

There are a number of problems that can arise from this code, but most of them come down to air/fuel mixture problems. So my plan of attack was to use a smoke generator on the intake manifold. Best place to introduce this is at the brake booster non-return valve. Sending the smoke into the intake produced nothing, but when I sent the smoke into the booster through the non-return valve I found the problem. The non-return valve has a little tube that I am assuming at one time had a hose attached to it. In this year they just capped this little tube. Well it appears this tube broke off and was introducing un-metered air. Interestingly the car was also throwing a anti-lock light. Once I plugged the tube hole the anti-lock light went out and it no longer throws the 1222 code. Double bonus.

I am now looking for a replacement non-return valve. Problem is they want ~$70 for the original valve with the little tube. Wondering if I can just put in a straight valve instead of this 90 degree valve?




1222 code problems:
air leak
defective Air Flow Meter ( AFM)
bad engine temperature sensor
incorrect fuel pressure
problem with injector(s)
defective evaporation system
empty gas tank
issue with spark plugs
problem with valves

[shogun]

If it fits, install a straight pipe non return valve. I assume they designed it in that way due to space reasons, but maybe even not for this engine, guess they also use it on other engines.