850 code 2-3-1 problems

easyrhythms · Post by **easyrhythms** » 29 Mar 2011, 16:39

Hey everyone, first time poster (i love this site). I've been having this problem with my 1994 850 Turbo for months now and can't figure it out. My car seems to run too rich and continually loses rpms and stalls out. It happens in every condition and does it whether i'm moving or not. When I accelerate, pressing the pedal sometimes seems to do nothing and the car will not move until it surges and takes off quickly. It sometimes surges intermittently when i hit the gas pedal. The rpms will often drop to 300 gradually and the car will attempt to stall. After this I am always able to start it right back up. The car has also lost about 1/4 of its fuel mileage. I've replaced the spark plugs, wires, distributor cap and rotor, and battery to no avail. The only code that I am receiving consistently is 2-3-1 on A7 (long term fuel mixture too lean or too rich in part load stage). I have also received an oxygen sensor code saying the oxygen/fuel mixture is too rich and a knock sensor code but they each appeared only once and not at the same time. I have tried unplugging the maf but that made the car run even worse. When I rev the car a lot in park I can see that the exhaust fumes are a grey color and there is sometimes a small pool of gas under the exhaust. Are there any common causes of a 2-3-1 code? I'm completely clueless at this point. Please help.

Thanks in advance,
David

Post by **jblackburn** » 29 Mar 2011, 18:20

Hmm...it actually does sound mass airflow related, but I'd hate to tell you to go buy one and not have it solve the problem. Do you happen to know anyone with an 850/-70 series that you could quickly swap sensors with as a trial?

The other possibility is that there's a large vacuum leak somewhere that is throwing off the reading between the MAF and O2 sensor and causing your car to run ridiculously rich.

easyrhythms · Post by **easyrhythms** » 29 Mar 2011, 18:57

I may just go buy a new maf then. Is there some sort of diagram of vacuum hoses to check?

Post by **jblackburn** » 29 Mar 2011, 19:09

There is indeed!

If it idles consistently, a can of carburetor cleaner sprayed around suspect vacuum lines can help you look for broken lines - you'll hear a surge in the engine speed.

easyrhythms · Post by **easyrhythms** » 29 Mar 2011, 19:14

Thanks a lot. I'll give it a try first thing in the morning.

Post by **Pauloil** » 29 Mar 2011, 19:55

http://volvospeed.com/volvo_repairs_how ... lines.html

that is water at end of exhaust

easyrhythms · Post by **easyrhythms** » 30 Mar 2011, 12:41

Well I didn't find any vacuum leaks. I guess that leaves the MAF. Any other suggestions?

easyrhythms · Post by **easyrhythms** » 30 Mar 2011, 15:02

I started cleaning the throttle body and IAC and noticed that there is an oily substance in the intake hose. Is this normal?

Post by **jblackburn** » 30 Mar 2011, 15:04

Yeah, a small bit of oil in the intake hoses is normal. If it's a lot, your PCV system probably needs to be cleaned.

If that does nothing for you, I think I would go with a new mass airflow sensor.

easyrhythms · Post by **easyrhythms** » 30 Mar 2011, 15:58

Are there any tests I can do for the pcv system or are there any signs of it failing?