Hello this is my first post, some back ground on the car it is a 1991 Volvo 240. About a month ago I got a 121 code witch is " Mass air flow meter signal faulty or missing". So I cleaned the MAF, sadly with brake cleaner and it totally destroyed it. So I bought a new $70 Chinese one from rockauto, and it ran alright. But then I got a 322 code which is " Mass Air Flow sensor burn-off signal missing or faulty (MAF wiring fault)" and a 231 code "Lambda control - too lean or too rich at part load". Ever scene then I have been getting about 10mpg or worse. And scene about a day or two ago it wont even start with out like a minute of cranking it over and spraying starter fluid into a intake manifold vacuum hose. This is a problem that I really need to be fixed because I have school and work to get to and from with this car, and scene i'm still in school i'm still very poor. My questions is what do I try, Should I get one of the serves books (chilton, haynes, bentley) if so which one. Can I check the wiring with a volt/ohm reader. Please help me.
-Travis

 

unplug the MAF

does it run better? if yes then its a bad MAF

go to a junk yard and buy a BOSCH one, the cheap ones do not work with Volvos very well

also STOP using starter fluid
that’s really meant for carbureted cars not fuel injected. I have never seen a need to use starter fluid on a fuel injected car. Plus it dries up seals and can do more damage than good.

 

So I got it running and then pulled the plug on the MAF and it ran worse, the engine shook and kept almost stalling but the it would catch itself.

 

try starting it with the MAF unplugged first, see what it does. When you unplug it while its running it may do that but eventually should default to a rich but stable AF mixture.

 

Basically code 231 is a reading form the O2 sensor saying the Air Fuel mixture is wrong

this could be caused by a lot of things. The code 322 is a code form the burn off signal of the MAF sensor. the wire you see in it gets really hot when you turn off the car to clean impurities form it. Mine is getting this code as well and it does not effect the performance of the MAF.

The fact that you had a very replaced issue/code before you change the MAF says perhaps the wiring is faulty. That’s what we are testing by removing the MAF signal completely.

Check out this video for general testing of MAF's

I don't know what all the specs are off hand unfortunately

 

So when I started the car with the MAF already unplugged it fired up almost immediately. It was a very rough idle and it smelled like unburnt gas like at a go kart race track. Then while rough idling I plugged it back in and it went back to a good idle. I will try plugging my volt meter up to the MAF cable tomorrow because I go to work in a few minutes. I'll respond with the results tomorrow.

 

Return this MAFS and get an OEM one, even if used.
Get a Bentley, the other manuals are useless. But you don't really need manuals, all info you need is on line, google, you will get your answer!

 

don't plug/unplug the MAF with the ignition on, that could conceivably fry things. always switch car off before plugging or unplugging it.