Anyone revived a MAF by cleaning it?
 

I may have a bad MAF in the 94 E320. Just checked and I have a new harness. Not sure about the throttle body or OVP Relay.

But I notice that if I unplug the MAF it'll run great (well as great as limp mode can be). If I plug it back in, it stalls and is all but un-useable once the engine warms up and enters normal run temp mode.

I'm really thinking this equals bad MAF sensor.

I sprayed a good amount of the cleaner on the wire/sensor portion of the insert and no change.

Curious if there's anything else I can do or if anyone else has had any luck with this?


If it's not something I can revive somehow, is there a way to buy just the Bosch insert? Any idea on how well aftermarket would work or otherwise?
I'm sketchy on whether or not this is my problem so I'd hate to dump a ton of cash into it.

I have on the BMW but not the Benz. Becareful of what cleaning soloution is used - some have suggested that simple green is to strong and leaves a residue. Electronic contact cleaner is recommended and using a cue-tip on the sensors.

I did clean the MAF on my W210 early on. It lasted for about 6 months. By that time new ones had come down in price so I replaced it. No further problems. The Chinese inserts are now so cheap, they are worth a try.

I tried all sorts of cleaners including SG, contact cleaner etc. What you need to clean, is the actual hot film or wire (not sure what a 94 used). Problem is that whatever reached the hot surface is now baked on. Solvents probably won't remove it. I never tried it, but something like oven cleaner is probably needed! I think I tried Q-tips, but also pulled something back and forth to try and abrade the dirt off.

My memory is bad, but whatever I did, it did extend the life. But now, I would just buy a replacement.

After going crazy trying to fix my maf code on a 1996 C280 it turned out to be OVP relay.This fixed 2 codes for me.If that does not work buy a german maf,not a cheapee.Cheap ones run good,no codes on new cars but can rich or lean and you will not know till you go for smog.Then thinking you have a good maf other parts will be changed instead.Not worth the savings for a cheap maf.
Thanks
Rich

Cleaning is not usually very effective on hot film because dirty is not really the problem. They just get worn out and tired. Hot wire often cleans up nicely. I'll say there is no insert available for a 94, and we'll see if someone can come up with a link to one. German Star has a nice summary of available inserts - Mercedes MAF Sensor

What are the fault codes telling you?

I checked the codes (after clearing them and making sure all sensors were connected and running for a bit).

Got a 4 and a 13, there was a 24 in there too but it didn't come back after it was cleared. Who knows how old that code was.

Definitely a MAF code in there though.

Is it a hot film or hot wire MAF? If it's hot wire I think you have a better chance of success. Many auto parts stores have MAF cleaning spray.

-J

Cleaning a maf works great...if the problem is that the maf is dirty. At least with benz that seems rarely to be the case.

Personally I'd replace it with an OE Bosch; the aftermarket ones are too unreliable, and finding a quality insert seems to be a challenge. Considering how long they last, and how critical they are to so much, the extra money for a quality part isn't that extreme. If you shop around there are affordable ones.

That said, however, unplugging a MAF sensor is a hit-or-miss test. When it's out of the loop, everything is set to defaults, so if there is something else causing the problem (say a different sensor, or even a vacuum leak) the default settings can mask that, took. However, with the MAF code showing up, that reinforces the idea.

Good luck.

Can we assume you're talking about codes on the DM? Have you checked the other pins? Why do you say you're getting an MAF code? Nothing but questions for now.

That was with the Arthur Dalton push button code reader. I think pin 8. According to my list that was a MAF code.

Which pin it was is really important. Most people giving code numbers without a pin number are testing just the DM on the built in LED. I think you're right - on pin 8 it's an MAF code.

Pin 8.

To update the thread: The problem ended up being the MAF sensor. Changed it and I've got an idle again.