Tonight I was going to adjust my '86 300E's mixture setting slightly rich to help smooth my idle. After reading the DIY article on engine controls and reading all the posts regarding lambda adjustments, I thought I was prepared.

Here's what happened. Hooked my meter to X11, diagnostic socket pin#3. Key on, meter read 30%. (coolant temp sensor fault I think). Started engine, ran fine. Meter read 50%. After warmup duty cycle fluctuated about 50-54%. Shut engine off, turned adjustment screw right, about a quarter turn. I did press down and engage adjustment screw below. No change in duty cycle. Re-adjusted screw another 1/4 to 1/3 turn, started engine and it ran extreamly rough. Duty cycle went down into to 20s.(Too rich). Tried to correct by turning screw left to lean, now car wont start at all.

I remember reading members' posts about overturning and being sorry they ever touched the adjustment screw. Well that's me tonight!

Any ideas on how to return my '86 300E to its former running state? There were no other symptoms before this, other than a slightly rough idle. Car ran like a champ. Car won't start now and I am in Lambda Crisis! Help!


Thanks in advance,


Blake
'86 300E

Blake:

I suspect you first read what Benzmac had to say in the following posts. Thought I'd pass it on.

starting my 300e

300E air flow sensor