phattbam

for those who would swap out with a new sensor... would you A) buy just the OEM Bosch sensor element and put it back into the tube or B) buy an OE non name brand tube with new element for the same price? both are BRAND NEW. I'm considering doing this to avoid having the CEL come on while smog testing which I have yet to pass.

Buellwinkle

What code are you getting? If it's a fuel trim or lean code like a P0170 or P0171 you can just clean the insert tip (the gold wire) with CRC MAF Sensor Cleaner, $6 for a huge can.

phattbam

I tried that. It's very possible that my filters are too filthy and need a cleaning prior to putting the sensor back in. I will definitely try that again before I use the new sensor though. $110 is much better than $288 which is the cost my MB tech gets it for from work(he works at an actual MB dealership not independent shop) that's still alot.

MB-BOB

I changed my air filters and cleaned the MAF with CRC product as Buell suggests. CEL Gone! It's been three weeks and still CEL is OFF.

I do wonder if it simply was the old, dirty filters placing the MAF out of range adjustment. If your filter(s) are dirty, pitch them for new ones first, to simply see if the CEL goes out. If not, then try the cleaner spray. Either or both are less expensive than replacing a (very expensive) part that may not need replacing at all.

Some will say this doesn't work, but you have two posters who say it does.

If your inspection is imminent, and the cures discussed do work, take it to an autozone or other parts place with an OBDII reader and ask them to test, then RESET to clear the codes. Otherwise you may have to drive it a few days to get the codes to clear by themselves.

phattbam

I have tried cleaning just the MAF sensor already with the CRC product, after about 40 miles it triggered the CEL. Ran out of filter cleaner/oil for both my filters. I use K&N filters in my stock air box and green filters in my Renntech CF box. I just need to clean them both.. and test them out with the original MAF sensor. if all is well. I have an extra sensor to keep for later or to sell along the ways. I just need this sucker to pass smog and I'm back to using my Renntech box again. Since no local shops carry Green filter kits.

MB-BOB

If you don't have time to clean them or run to the parts store, then run the engine (stationary) with the airbox off for a few minutes to see if the light clears. No harm in that, and it might tell you if it's the filters.

phattbam

never thought of that... I'll have to give that a try thanks

sirenebekim

you've just undone everything i've ever learned about air filters... What about when you work on the car, to put a rag over the open intake? I strongly recommend NOT running the motor with out the air filter. MBBOB, what makes it ok to run a motor with out a filter? I'm not being mean, but I just wana know why you think its ok to do that.. maybe it is ok, but, it doesnt' sound like something i would do with my car

SeaCoupe

Man, sometimes I get scared about the amount of myth and misinformation I see.

You CAN run the motor without the air filter. I would not drive it that way under any conditions, but at an idle you CAN run it without the airfilter.

Just insure that you don't provide a possibility of putting something into the intake.

E

phattbam

I've driven it before without the filters around the block.. that thing sounds like a monster..

MB-BOB

It's perfectly OK... Back in the day, the simplest way to clean dirt out of a carburetor was to remove the filter assembly and spray carb cleaner down the throat with the engine running.

Hell, I had a '77 Accord 5spd... 60 hp (carbureted) on a good day... I took a family trip to Vail, CO in 1979, and I was told by locals I would have to remove the air filter assembly to make it up the mountains and through the high passes. Sure enough, I HAD to do this to make it up the grades... removing the filter gave back two gears to me. I drove it 30-40 miles that way up, and the same on the way down. I wouldn't advocate driving a car in a sandstorm this way, but in the crisp mountain air it was just fine. That car is still running somewhere in Mexico to this day, I just know it.

Now, if anyone thinks they can rest a 64oz slurpee or a set of tools on the intake plenum and do this, then get in line for a Darwin award. But with reasonable caution to secure loose items in the engine compartment, you can run the engine without the filters in place, when the air is clear, etc. The intake is not a vacuum cleaner like a jet engine is.

sirenebekim

wow thats amazing i learned something today.. thanks mbbob!

Buellwinkle

I had the K&N for my 2002 C230 and it didn't look like it really fit all that well. It could be that dirty air is bypassing the filter and contaminating the MAF. Also, the MAF code will come back quick but as a pending code but may not turn on the CEL until several miles later. Also, make sure you remove the insert and really spray the gold wire heavily, blast it. Also, look for oil residue in the intake before the MAF, there could be some check valve/egr valve that's clogged thats backing oil back into the intake.