My 1990 240 had the check engine light come on about two months ago.
I checked the codes and found that with the pin in the #2 position, I got the following codes:

2-3-2: Fuel system compensating for rich or lean mixture at idle
and
1-1-3:Fault in fuel injectors

I can clear the codes, and generally go for between 2 and 10 days without it coming on again.

I have noticed that, occasionally, the car smells like it's running rich, and when that is happening, it also idles rough, which makes sense.

I'm wondering, where do you all think I should start? Injectors? O2 Sensor? Injector O-Rings?

I thought it was the 02 sensor, but the fact that I can clear the code and get by for a while without it makes me hesitant, plus the code specifically says there is a fault in the injectors...should I just put new ones in? I see them for $69 a piece at NAPA and Ive got 272k on the car now... probably original injectors :/

Thanks a lot guys! Love this forum, it's saved me many times, but I'm kinda stumped.

 

too high fuel pressure from a bad fuel pressure regulator? defective coolant temp sensor (ECU thinks engine is cold, so it enrichens it). bad injectors that leak too much gas?

[I'm really just guessing here]

 

Thanks for those leads!

As long as the regulator isn't letting fuel into the vac line that connects to it, it should still be good, right?

Ill give the coolant temp sensor a check--any guess how to test that?

I think it's the injectors, so I'll probably pull the plugs before I start it one morning and see if they've been leaking.

Thanks!

 

you test the ECT with an ohm-meter. see Engine Sensors