We have a 1990 760T with the Check Engine light on. It has a lot of spark knocking going on. The engine codes we are getting are 221 - Fuel trim too lean at part load, and 231 - Fuel trim too lean or too rich at part load.

We checked for false air leaks between the engine and the AMM. Nothing. We replaced the O2 sensor. No change. We replaced the AMM, but with the new one, the car would not run - bad part, possibly?

Now, prior to all of this, we've had trouble with the alternator charging. At start-up, both the SRS and ABS lights stay on, until you rev the engine to a high enough RPM for the alternator to start charging - then they go off and no more out of them. Don't think they're related, but would also like to fix that annoying problem. As a side note, we have a 1989 760T that has the same type of symptom - only the overdrive arrow is the light that stays on until the alternator starts charging. Of course, the A/C won't work until we get "full power" from the alternator either - but it's the most puzzling thing. We've been driving it that way for several years and 150k miles or so. It's only a problem at start-up, and we couldn't find a reference to a similar problem.

Thanks for any advice or experience anyone might be able to offer.

Mary-Belle
simmons@asheboro.com