hrichards

I just removed my mas air flow sensor from my 1998 slk230. I have cleaned it about every 6 months when it starts acting up. I remove it, wash it down with brake cleaner, and put it back in, reset the mil light and drive it like usual.

This last time, I wasn't able to get to it as soon as I normally did and i drove it for about 30 days this way. It had a dead spot arround the 2000 rpm. It also had limited power at other rpm's, but I can get the car up to 70 to 80 miles an hour to drive it normally.

I have heard that I could burn the valves, melt the CC and plug the muffler. I know, I know. That's why I took the maf out and cleaned it.

Well, since I have cleaned it, the power has decreased quite a bit, but the dead spot is still there. I can hardly drive it now, so it is parked.

I was going to replace the mass air flow sensor and jotted down the numbers off of it.

They read F00C2G2025 on one line. F 00C 2G2 025.

On the next is 966 012B

I looked up this number and can't find anything, so I looked up my car details and get this mas number from Bosch 0280217114.

Is this the same?

Also, could i have driven it so long this way that the computer "learned" to be this way? Does resetting the MIL, reset the Learning? Do I need one of those Carsoft interfaces to give my computer a reset?

thanks so much for you time!

bazzle

F 00C 2G2 025. is the number you need. They are made by Bosch. If they have a xref to one of their numbers it should be OK. DO NOT buy off ebay one that says it is the same as or similar too.

Only buy a Bosch or MB BRANDED item.

Many, many owners have been caught with copies that are not the same.

Bazzle

contractsguy

I agree with Bazzle. Only use the Bosch brand.

I had problems with the sensor on my 1999 SLK 230 and cleaned it a few times. The engine would run better for a while, then the light would come back on and performance would decrease.

I didn't want to spend the money, but if you have a MB that is what it takes some times.

Spend the money and your car will run much better.

Search this site and you other who have had the same problems as you are experience. In the end they spent the money and bought the Bosch part.

Happy Driving

hrichards

THanks for the great responses. I think I will dig deep into my pocket for the Bosch part. My concern, is that every time in the past, the MAF sensor has ran great after a cleaning, this time, there is little change.

I have never gotten a check engine light referring to the MAF sensor. I do not know the code, but the explaination is always something like "unable to adjust mixture. Lean condition Bank 1"

Along with this, I get a shiftdown from 3rd to 2nd gear solenoid error, but I think that is because of the way I drive it when it is doggy, I really light foot it.

Can the carsoft 7.4 reset the learning of the engine? I was thinking of purchasing one off ebay since I have always had a SRS light on(I think since there is electrical tape over it) that I want to find the code for.

Maybe the engine has learned to drive so badly because of the MAF sensor being so far out of wack for the last 2500 miles or so. By resetting the learning on the computer, maybe it will be ok?

I drive 85 miles a day to work and back. I did clean the mas sensor, and drive it to work and back once, which was 85 miles of interstate, but I didn't see feel any improvement. There were no check engine lights, but I don't usually see them for a few days, and since it was running a bit worse than before the cleaning, I wanted to just ask the pro's here.

How many miles should I put on before I will see an improvement if any?

Buellwinkle

While brake cleaner will clean just about anything, consider that it's likely harming the plastic on the sensor and it may leave a slight residue that's causing you to clean it regularly. I used CRC MAF cleaner 2 years ago and it's still fine.

contractsguy

HRichards,

The MAF is extremely sensitive. I have found cleaning it works, but only temporarily. Suggest using a MAF-approved cleaner if you are going to clean it. Other cleaners may leave an oily residue and make the situation worse.

Also, if you are using a renewable air filter and you spray the air filter with oil the MAF problem may reoccur quickly.

With the MAF replaced, the best way to get instant changes is to disconnect the battery for appx 20 minutes. This will reset all of the computers. Recononect and start driving. The car will now re-learn how you drive. Try this and see if it works.

Simple and cheap.

REMEMBER - when you disconnect the battery your radio will reset if you have an original MB radio, so you will need your reset code - check out the papers you received when you purchased your car and you will probably find it.

Happing driving

hrichards

thanks. My concern is the radio. I do not have the key for it, becuase the radio was replaced with a mb radio from the same year. The original owner never gave me the keycode. He says it is written on the radio cover, but I haven't figured out how to remove the radio! I keep waiting for my battery to die and be forced to take it to the shop to fix it. What's the tool used to remove the radio?


I'll stop and pick up maf cleaner tonight from my local auto parts place and give it a squirt.

contractsguy

HRichards,

In order to get the unlock code you need the serial number from the back of the radio. To get the radio out you need the special tool. I tried to make my own tool, but was unsuccessful so I purchased my own set. The tool is not expensive, but will take some time to get them if you order one. I'd be happy to let you borrow mine. Send me a private e-mail and give me your address and I will send the tool to you. With the serial number you can go to your local MB dealer, prove you own the car, give them the radio serial number and they will give you the code. Should be free of charge. I was told that I had to go to the dealer in person and that I could not get the code from someone over the internet. However, I was able to do it over the intenet; give it a shot.

Let me know if you want to borrow my radio tool; I am glad to help.

hrichards

Thanks for the info. I did order the key already to remove it. Once I do that, I will remove the radio, hopefully without unplugging it so I can get the serial number off of it. I was told it is written on the top of the radio, so it might be a simple as removing, recording, and installing.

I also was talked into buying the carsoft diag unit. My buddy and I will split the cost since he works on cars and asks me for my technical expertise some times.

hrichards

OK, I think it is definately the MAF.

I got MAF cleaner and cleaned the heck out of it, and reinstalled the maf. The car would not idle at all for the first minute or so, but I sat in it and watched the rpms go up and down as it hunted for the right settings.Then it started to idle fine, this is working. It is relearning how to idle. Well, I drove it arround the neighborhood, which is hilly, and when it would start missing going up a hill, I would hold the pedal there for about 5 seconds or so and it would clear out and accelerate up the hill. I again thought, "This is learning and it's going to work".

Well, I drove it for about 30 minutes this way and I saw an improvement at every hill. It still had trouble at the very low rpms, but after about 2000 rpm the engine took off.

After quite a slow ride through the neighborhood, probably 15 miles going no faster than 20 miles an hour, I looked down and the check engine light was on. I had my scanner already hooked up to the obd port, and scanned for codes, but none showed up. I had to turn the engine off and back on to get the codes, and a wopping 9 codes came up. A new record! 7 of them were P0300-P0304 cylinder misfires 1-4 and mulitple misfires along with pending ones as well. The other 2 were P0170 codes, one at the beginning of the code count and another one that was #9 that was pending.

I reset the computer and started the engine up without any idle issues, and it seemed to run ok in the neighborhood, but on the highway it was very poor acceleration.

I have not unhooked the battery yet, because of my radio codes not being pulled yet. But I do plan on trying that as well. I have the radio removal key on it's way to me.

Thanks

hrichards

OK, a long time ago, I replaced my maf back at the beginning of this thread. I bought it on ebay and it was only the insert, not the whole thing. Anyway. Things are working great, I've got 190K miles on it and it runs like a champ in the winter. When the summer comes, the oil starts getting on the maf again and I have to continue to clean it.

I'd love to find out what to replace to keep the oil from getting into the maf.


We just had a baby so my little car is about to be put up for the next owner.


Today, I removed the front bumper to remove the air cooler. I expected there to be lots of oil in the air cooler, but it was bone dry. I read on here that some one got 2 tablespoons out of theirs, and mine is not that bad at all. There was oil, but not where i expected it. The oil was in the elbows before and after the air cooler, and it was about 2 tablespoons. Not enough to cause any trouble, from the looks of it.

Tomorrow, I plan on washing out the air cooler, wipe out the pipes, and put it all back together, but i know I didn't fix anything yet until I fix some kind of tube that moves the oil fumes from the air intake?? What is this tube and where is it?

hrichards

I haven't gotten around to washing anything out yet, but I plan on this weekend. I'll give you guys a full report.

hrichards

I took the front bumper off, pretty easy to do. One person job for me.

I took the air cooler off and washed it out, it was a little oily but not alot. The place where I found the most oil was in the rubber hoses connecting to the air cooler. There was maybe a teaspoon of oil in them. I put it all back together and it performs about the same. I can't say I did any good.

I did reset the computer and cleaned the maf. After cleaning, I have a rough idle, but the performance at top and mid range is better, but only time will tell if it did any long term good.

RicksterSLK

So the question remains - how do I stop the MAF from getting ugly?

I have a 2003 SLK with 60K miles on it.

After around 40K, I started getting a "surging" and P0101 code CEL.
The surging is at idle (500-900rpm up and down at about a 1-second interval) and at about 3800RPM (feels like a "tugging" on the car at constant throttle).

The dealer replaced the MAF ($2K) and everything everything was great... for a while.

Now I have to clean the MAF about every three months (can't afford to take it to the dealer each time!)
I'm using CRC MAF cleaner.

The last few times I cleaned it, there were paint flakes (silver, from the engine insides?) in the screen.

There is always a bunch of oil in the elbow where the rubber hose from the MAF connects to the intercooler.

I've tried cleaning the oil separator thing on the breather box (sc muffler, not the air cleaner).

I even removed the breather box (be real delicate with the SC cut off flap it's a $1K item).
About 3 table spoons of oil came out of it. I washed it thoroughly with hot water and Dawn detergent.

In retrospect, I should have drilled/tapped a drain plug on the breather box while I had it out....

Seriously though, other than disconnecting things, what's the long term solution?