That's a pretty informative post. Thanks.

Brett

 

Interesting and useful information, but what is the name of the part and where did you get it?
It looks like the MAF. Did you replace the whole thing or the connector to it?

 

Link to the part and where i bought it

It is the entire housing including the Mass Air Flow sensor and connector

P.S. the name of the part is in the title of the thread

 

Ditto re. a useful post which should help out many on the forum as those seem to be common and persistent symptoms. Glad that it was so successful for you!

Were you getting any Check Engine Light issues or did you check your codes before you replaced the MAF?

 

I had a MAF / VAF code. Though this code did not show up until my problems became much worse. My initial problems (the car balking in traffic) caused no codes.

I also have an 02 sensor code. I need to replace the O2 on one of the banks, i forget which one. THOUGH...and i know this is optimistic, the O2 code could have come through because of the weird readings it was getting as a result of the MAF causing such messed up air fuel mixes. Though i'm pretty sure it's just a faulty sensor.

Those were the only two codes i had before i switched the MAF out.

 

I used to have a Ford a long time ago that would give 02 sensor codes and cause strange problems and it was the MAF sensor.

 

Partstrain has it for 212USD with a core, for older W140s with the metal housing, I think I should order one quick, Earl knows what I'm talking about, my car never runs smooth before/after new caps and rotors, wires, plugs, coils, one new injector etc, time for a new MAF YAY!!

 

Thanks bazookatooth,

Good info:thumbsup:

 

Same Issues as Failed MAF

I have exactly the same symptoms as yours on my 1996 S420. It lunges forward, suddenly die, erratic idle, does not respond after stopping, etc, etc. I changed the vacuum lines, breather hoses to no effect. I will try to clean it first with CRC. Can I clean it on the car or do I have to pull it out?

A lot of members say that this is indicative of a MAF sensor failure or problem with it.

 

Could plain rough idle be the MAF?

I have idle issues w/ my car stopped in drive with the brake on - nothing like is described here in earlier posts (no stalling, lurching, etc...), just enough intermittent rough idle to annoy me.

I've replaced the plugs, engine mounts, run BG 44K through twice but no improvement. Anyone know if this could be early symptoms of a MAF problem - does the MAF dies slowly or as edong mentions above, can it be cleaned?

My car is a 1996 S500 w/ 139K.

Thanks for the advice.

 

I have idle issues w/ my car stopped in drive with the brake on - nothing like is described here in earlier posts (no stalling, lurching, etc...), just enough intermittent rough idle to annoy me.

I've replaced the plugs, engine mounts, run BG 44K through twice but no improvement. Anyone know if this could be early symptoms of a MAF problem - does the MAF dies slowly or as edong mentions above, can it be cleaned?

My car is a 1996 S500 w/ 139K.

Thanks for the advice.

Did all the same as you, would also like opinions on this!

BUMP!

 

MAF smoothed my engine a little, a very tiny amount. Still not close to perfect at all. My car seems to have a miss upon heavy accel and idle but the ignition system in it's completeness is new, from the plugs to the coils, new new new, no improvement. Maybe one of the 2 fuel pumps is done?

 

I recently encountered some of the same problems on my 2002 C320. I was waiting in a parking lot for about 10 minutes with the AC running max, went to pull out, car died. With accessories still on, restarted the car went to take off, car died again. Turned off all the accessories, car started and made it home a 1/2 mile later. I take the car in to the shop, they say it's a failing fuel pump, fine, whatever. Pick the car up from the shop at closing and it hesitates as I go to leave, make it home, drive it the next day to confirm the hesitation and OH BOY it runs like crap for sure now whether the AC was on or not. Hesitates on take off from a stop, idles rough, wants to lunge forward at a dead stop. Take it back to the same shop, they finally managed to get an error code that pointed them to the MAF, what a circus sideshow let me tell you.

It really acted initially like a fuel delivery problem of some sort.

 

Is it possible to distinguish/diagnose between a faulty MAF and a bad engine wiring harness?

I'm having the same stalling-while-standing issues, but I also have warm (no) start problems. No check engine light though (after I replaced a crankshaft position sensor)

 

It would help if we knew what year and engine you had in yours.

 

Thanks you so much! This helps me greatly. I'm gonna replace this. I really cannot afford to have Mercedes Dealership do something for an outrageous price when I can do it myself. I got codes that have to do with the MAF. I also had to replace my transmission myself. Easy. (kinda) You can do it all from your driver's seat. I saved over $1200 according to the quote they gave me.

 

this thread should always be up. since this saved my w140 and i had all of these symptoms too and changing the maf saved me you would never guess how much stuff i changed before finding out it was the maf. my maf got ruined thanks to a friend with carb cleaner. the worst part is when you make a turn and it stalls

 

NHZRUTHLESS818

You didn't change the MAF, you changed a whole lot of stuff ending with the MAF.

So it is logical to assume that it was not just the MAF which solved all your problems.

 

I have all these symptons as well, but my 93 300se is also hard to start. When I disconnect the MAF it is still hard to start but will ultimatly start after a few tries. It still dies on me even with the MAF disconnect although it happens less frequent if I had it still plugged in. Shuts of especially in turns and taking off also randomly while rolling. Alt/Battery giving 14amps so they are fine, fuel pressure is 50-60 so thats fine. Could a bad MAF also contribute to hard starts hot or cold?

 

well funny thing is what ever i changed nothing fixed the issue until i did the maf. i did one thing at a time and there was no change until i did the maf. like i have said in the past i don't like to wait for repairs i will change out everything and pay hgih prices for parts until i fix my car.

 

Doyou have to re-program, or is just replace ?

 

I've started having the same problems and my check engine light has also just come on. We pulled the codes and the MAF and knocking came up which I assume is due to the wrong air mixture (too lean maybe?!?). I will be looking for a MAF to replace mine - any suggestions as I don't want to pay dealership prices!

 

No one wants to pay stealership prices ....

however I would suggest that you get a new one if you can.

Once you have it, and installed it will take some "tuning" effort for the car to come back to her smooth senses.

So you are stuck either with a stealership or a very good workshop with a good computer system and a wise mechanic.

 

Could you have MAF problems, and no engine light ?

 

Hi,

Would think so. I had a MAF problem.
My car does not have a check engine light (and no N59 module), but checked all other codes. MAF was just very dirty as far as I can tell, not actually broken (broken wire or so).
My car ran rich (could smell in exhaust), at the petrol station I ran poor lol.
Had rough idle and problems when the car was warming up, lack of power when trying to accelerate.
All gone.

Cheers

 

MAF?

Hey guys,
I know I'm in the wrong area but I have a 1992 400E(119.74) and can only find help with my car through the W140 forums. Anyway I replaced my upper wiring harness, complete major tune-up, and I'm having many of the problems listed here that seem to point to my MAF. I have not yet done the ETA but have none of the strange warning lights etc. usually listed for that part. However, the car is exhibiting all of the above issues. It seems to have progressed to a point that I will not drive my car now. I will first try e cleaning the MAF and the throttle body, then if that doesn't work I'll move to the MAF replacement. I'm thinking that I'll go ahead and send the ETA off to Beckmann for a rebuild at the same time. The issues seem to have progressed to the current almost no run status. Weird how it will snap out of it and run like a raped cat if pressed hard. At idle it is crap now. It first started that it would seem to go into limp mode unless I accelerated vigorously past 40mph. Then it would run great.
Apologies for being wordy here but the alternative is to be vague.
Any advice would be greatly appreciated.
Curt

 

Hey guys,
I know I'm in the wrong area but I have a 1992 400E(119.74) and can only find help with my car through the W140 forums. Anyway I replaced my upper wiring harness, complete major tune-up, and I'm having many of the problems listed here that seem to point to my MAF. I have not yet done the ETA but have none of the strange warning lights etc. usually listed for that part. However, the car is exhibiting all of the above issues. It seems to have progressed to a point that I will not drive my car now. I will first try e cleaning the MAF and the throttle body, then if that doesn't work I'll move to the MAF replacement. I'm thinking that I'll go ahead and send the ETA off to Beckmann for a rebuild at the same time. The issues seem to have progressed to the current almost no run status. Weird how it will snap out of it and run like a raped cat if pressed hard. At idle it is crap now. It first started that it would seem to go into limp mode unless I accelerated vigorously past 40mph. Then it would run great.
Apologies for being wordy here but the alternative is to be vague.
Any advice would be greatly appreciated.
Curt

My suggestion is to try and unplug the MAF and see if the car runs fine or not. What happens is when the MAF is unplugged, the fuel/air mixture is mixed based on pre-defined values. So if your current environment is near those values, chances are your car will run fine. If not, you will either be burning too much or too little fuel. This was how I determined my problem was the MAF. I also had those symptoms, I also thought wiring harness/throttle body. I figured it wouldn't hurt trying the run without the MAF, and I was right, it ran perfectly fine, all the problems went away. It was only at night that the mixture was wrong and I was burning too much gas. This is why it is not recommended that you run it a long time with it unplugged, you can kill the o2 sensors or catalytic converter etc. I tried cleaning the MAF but that did nothing. I never got any warning lights on the dash either, only when I unplugged the MAF after a few start-ups the CEL came on. Replacing the part ~$200 (remanufactured from AutohausAZ.com) everything was back to normal. I hope this helps.

 

i noticed my current non benz runs a little better when the maf is simply cleaned.

i would start there by at least cleaning it with the proper cleaner and see if there is even a hint of improvement. if not, start chasing down any vac leaks, fuel pressure, etc.

 

^^ what is said above is correct.

and once you have done that step, and find out that the problem IS with the MAF,
then I suggest before you replace it, you may clean it using AC Delco or some thing.
Remember to clean both the sensors, without touching any one.

MAF is an expensive part, so best to try all options before changing.

 

Hi, i have a C320 W203 2001 with the CEL on and with problems stalling at stops and when long decelerations. After that i have to wait longer each time to start the engine cos it tries but dont start. New Alternator, battery full, alternator working cos charges... any ideas??
Im doubting about the MAF and the fuel pump... but it havent done any thing until three days before we changed the alternator... you think i can had forgotten any thing that is bringing me those troubles??

 

i havent unplugged mine and drove it yet, but i did remove it and clean it out and reinstalled it and my issues were there, but nowhere near as often, or as severe so im thinking its my maf messing up and mine did have a code according to the star diagnostic for the maf.

im thinking its just time to replace it.

 

Original poster, that stupid car.......I think it must be a loose connection since the top wiring harness install. It runs perfect except once in awhile now. Some one told me that it sounds like the cam position sensor. I have taken all of the connectors off and cleaned them with spray electrical cleaner and the car seems to run great. The stealership told me that the ASR cars are highly sensitive to rear tire sizes and the car had mismatched ones. I put new ones on and it seemed to help but I haven't removed the MAF for a thorough cleaning yet. I just always thought that if an electrical part is toast then it will not work properly again. This thing is driving me crazy. It has to be a connection somewhere. It may be off to the doctor soon.
$$$ challenged right now though. Another guy told me he thinks it is the voltage regulator. He says this part is so over looked and causes all kinds of weird stuff.
Thanks guys for your help.
Curt