Do I need a new maf sensor?

[mss5413]

I have had off and on acceleration problems with my car. Last time it seemed like it was the maf sensor connection because when I had disconnected it and reconnected it, it fixed my rough idle and acceleration problem, but the funny thing is that I never saw the malfunction lamp come on at the ECU. This time I tried cleaning the sensor with carb cleaner because the acceleration problem came back. I seems like I have tried to clean this sensor almost 8 times already, this seems ridic. right? Why should I clean my maf sensor that many times? Should I just buy another maf sensor? If I do, where should I get it? I have read in these forums that maf sensors and o2 sensors are common problems on the 240, does anybody have any input on that?

[Acuratechva]

what do you mean on an off acc problem,/? see i got this same problem ...well i think it's same . i just made a post read up tell me i fyou think it's smae problem

[JPG0511]

sounds like the same problem i have. it is like the car is allmost missing but not much. it is weird. how are you cleaning it. at the conection or the inside?

[deeznuttz2]

I've just changed my MAF....I was told that because of my K & N filter, that is not tied down so the sensor moves up and down while I drove. Brought a used one for $65 on ebay....just put it on today, the car is running better, but gotta monitor the gass mileage....the dealer quoted me $500 for a new MAF...

hey are u running very rich cuz of your f'ed up MAF? Cuz I was from 22mpg to 15mpg....I hope I get my gas mileage back because I've got to smog my car.

[mss5413]

what i mean by on and off is when i fix it, it will come back say 2 weeks later and i am tempted to think i have a problem somewhere else. A friend of mine from work was riding with me while my car was bogging out like it is now, and she said that she could smell fuel fumes. Maybe I am still running rich, I don't know. By the way, I am cleaning the sensor on the inside and outside. I am spraying the little internal resistor with carb cleaner and also spraying the connection itself. Is it worth the risk of buying a new sensor, since it did come out of a salvage yard, or does the fact that it came out of a salvage yard have nothing to do with it? Maybe some of you having the same problems can give me some more input. Thanks. I will keep ya'll updated if I find a solution or get any ideas.

[onosqv]

what i mean by on and off is when i fix it, it will come back say 2 weeks later and i am tempted to think i have a problem somewhere else. A friend of mine from work was riding with me while my car was bogging out like it is now, and she said that she could smell fuel fumes. Maybe I am still running rich, I don't know. By the way, I am cleaning the sensor on the inside and outside. I am spraying the little internal resistor with carb cleaner and also spraying the connection itself. Is it worth the risk of buying a new sensor, since it did come out of a salvage yard, or does the fact that it came out of a salvage yard have nothing to do with it? Maybe some of you having the same problems can give me some more input. Thanks. I will keep ya'll updated if I find a solution or get any ideas.

Actually, I think the correct way to clean the sensor is to drip carbcleaner/alcohol above it and let it slide down over it - not to spray it directly because it's a sensitive device.

There are so many ways our cars can get rough idling/acc problems it's not even funny.

For my problem, after cleaning the sensors, I also noted that the sensor plug was slightly hitting the hood, so I rotated it a lil so it cleared it.

Another thing you may want to check is removing/plugging/cleaning the aiv (the smaller resonator box that connects to the intake via a smaller tube. You can do a search for aiv removal/cleaning. This usually cures up a lot of the idling problems that come and go. To test it, just plug up both ends temporarily and see if your problem goes away. If it does, that means the aiv is dirty and actually sending exhaust gas into your intake.

Also, have you replaced your spark plugs, wires, dist cab, and rotor lately? Check those to see how they are doing. Just to rule those things out.

Hope that helps some.

[mss5413]

Is it a small black box that is directly attached to the airbox via small hose or is it on the other side that opens up by four screws?

[mss5413]

Did you mount the maf sensor differently after rotating is 90 degrees or did you slightly rotate the whole air box?

[onosqv]

The small black box attached via hose.

Basically, block off the hose going to the intake & either block off or put a breather on the small box for now. This will give you an idea if it has anything to do with your problem. You can use radiator stoppers (about 3/4" or 1/2" or so).

[mss5413]

I tried removing the black box, so-called the aiv and drove it, but did not notice a difference, any other ideas?

[onosqv]

I tried removing the black box, so-called the aiv and drove it, but did not notice a difference, any other ideas?

Hmmm, well that narrows it down, so at least we know it's not that.

What have you changed so far?

Have you changed the o2 sensor? Checked the spark plugs for oil/contamination/gap? Check the spark wires? Checked your dist cab + rotor?

And can you elaborate? What kind of rough idle (a little, or alot or rpm surging/dropping)? What kind of acceleration problem (1st gear, 2nd gear, rpm range, characteristics)?

I may not be able to help, but if you list these things, I"m sure many other more qualified members will be able to narrow down your situation even more.

[mss5413]

Sorry, I don't mean that I have a still have a rough idle, that is not a concern anymore. And it doesn't feel like it is missing. What it feel like is that it is not getting the right fuel delivery, and the way that it drives, it feels like it is the same problem or at least same symptom that I have had off and on in the past. When I say off and on, I mean that when I fix it, it seems to have trouble again later on. Oh, please clarify exactly what you did as far as rotating the maf connection to clear the hood.

[onosqv]

What do you mean by right fuel delivery? That may have to do with the fuel pump or fuel filter. The only way you can truly verify that is to get a wideband sensor that would tell you your air/fuel ratio's - or get a dyno when the problem occurs.

Exactly what does the car do when you feel you are not getting the right fuel delivery??

As for the maf rotating, I have a cone filter (like one of the pics in the sigs above). I just had to rotate the part w/ the maf clockwise in regards to the intake path as the origin. Since you have an airbox, that may not work great with you.

However, to see if you even need to rotate the maf, you can look at the top of the connector, if it is being eaten away and getting exposed, that probably means the hood is rubbing against it, which means every time you fix your problem, a few weeks later the hood could have knocked or rubbed it the wrong way.

Hope that helps.

[mss5413]

I mean I lack acceleration the whole time that I drive it. Like I mentioned earlier, my friend said that she could smell fuel while we were riding in the car.

Fuel pressure is o.k.

Fuel filter is fairly new.

Don't know why working with the maf connection fixed the problem last time, both bad idle and poor accleration, and doesn't fix it this time???

Remember, the idle is not an issue anymore, just poor accleration.

Could it be injector related?