Hi,

bought new MAF (and eventually replaced it 6 times within a week!) due to p0102 error happening every now and then (once every 2 or 3 weeks).. anyway, the maf is verom vdo (siemens) and bought from a well known maf shop.. when i look at the new maf reading.. at idle it shows on avg 1.8 g/s and at some moments i can see it go as low as 1.08 g/s .. the max is 156 at WOT..

now, there is NO maf errors (or any other error), but when the car goes into operating temp (80c) after driving, when i stop and put on P or N, the rpm raise to 1.4K and keep steady there until i turn of the car and turn it on back.. if the A/C or high beam are on, the RPM will stay steady at 800 when i put on P or N!!!!!

The rpm in other situations is stable, some rare ocassions, when the car is warm and i turn it on, i see it fluctuating -+50 and the car hesitates very little, and this disappears if i put on D and drive the car.

checked form vaccum leaks (with wd40 spray) only sprayed around the air filter and maf and under the filter (in case of the 12$ hose!) and nothing with revs changed whatsoever! - didnt spray on the EGR or under bullys just in case the area is hot and goes on fire! but inspected by eye and all lines look like brand new!

checked the connections, all look clean and sparky! and just in case sprayed them with elec connection cleaner..

when i checked obd2, i can see that when the car goes into close loop, it gives within a min closed loop - FAULT. but i cant see what the fault is!


Car: w209 (similar to w203 engine) clk 2004 1.8L petrol kompressor M271 Engine. car is only 40k miles and very little driven, well taken car of.. new spark plugs (after the issue arise), air filter is getting changed every 2 months as a prevention for maf damage..


what i noticed also, that after changing brake pads, the car braking is not as usued as to be.. a small touch on the brake pedale is enough to hold the car.. now i have to press too much (as if i was driving my grandpa pickup!) the pedal has the same feel, but not same perofrmance -- not sur eif this issue is realted to the above isssue or not!


any help is appreciated!

any advice?

 

With an intermittent code you need to have a computer scanner that can give you freeze frame data, basically a snap shot of all sensor readings when the code is set. Also, seeing it on a graph is a must for intermittent issues. What is your fuel trim doing?

 

The LTFT is 12.5% and the STFT is ranges from -17 up to 25 and when the high steady rpm happens when idle the the fuel trim status is CL-FAULT and the STFT is 25% and the maf reading is around 2.5% and TPS is 2.7 and gret raised to 3% and stay there so long as am in idle. the boost pressure goes down (less than 40) where in all gears or other random drives it goes more than 40. the coolant temp is normal (avg 80c) and IAT when i idled in 19c weather (no sun, its england!) I can see it: 32c - all other readings look normal.. unless there is something i should read and i didnt notice!

any way to benchmark? engine light is on today (and the car shakes with very slight rpm fluctuating) sometimes and the high idle is still there, and if i unplug the maf, the car idles fine and no high rpm when warm and in P , so i cant hook the obd2 and see whats wrong with readings, but need to see what to read, if you can point to me

note: one friend suggested that i clean the maf even though it arrived sealed (at the other 5 ones!) but i hated to kill 500$ thing while nowing its brandnew and no sense to clean it.. Im trying to figure out if there is a leak but couldnt find it when i sprayed on the hoses and after maf, maybe because the ecu correct air faster than what i can notice.. Im lost

thanks again!

 

I noticed that sparkadv is flucuting very high and very low making the car shake while the rpm look steady!!

attached the saved log for pcmscan: http://www.2shared.com/file/bt7xwHrv/banana.html

readings: freeze frame and error corde (the rich bank appeared today after hard driving)

 

Hmm,naturally the first thing that comes to mind would be vacuum leak. High idle, rich fuel trim, indicating it is trying compensate. I had best luck checking vacuum leaks with Gum Cutter or carb cleaner, not wd40. Did u check around intake manifold?
Did it run like that b4 you put on the new maf?

 

it runs lean, and only happened after the new maf..
tried wd40 and carb cleaner and both did same.. on m271 the intake system is not visually easy to inspect or reach all pipes without taking the filter box.. put chinese cheap banana and no more high idle.. just crap performance.. will settle for it for now, until further notice! it exhausted me for 2 months..

 

Chinese banana Haha. Interesting it didn't do it b4. Yes it is lean and the computer is trying to force more fuel. Have to find a diagnostic tree and dbl check the wires going to the maf? Oh well, good luck, cheers!

 

Guys

I have all the same as above, I tend to think there's an airleak and the MAF is over compensating and making the idle too rich. Ive looked everywhere for a leak though not tried carb cleaner.

I did find a vacuum pipe not attached to anything which seems odd - I know old cars used to have a vacuum pipe not attached, didnt think this was the same


I also found this pipe had come off..


Ive put everything back and still the same after an OEM MAF... £40 on fleabay. Kinda wondering if a Bosch would solve the issue. Ive had everything else apart and cant find anything wrong or where air could be getting in

 

A few things to check:

1. could be bad mass air meter. The cheap non Bosch Ebay units have a reputation for being faulty out of the box. Get the genuine Bosch oem replacement if possible. Autohaus, AZ has them for low prices. In a pinch try the CRC elec cleaner on the mass air meter element. Some find this will work for a while.

2. 12.5%+ ltft is def a lean cond and the computer is compensating by adding fuel. You need to hook up DAS star (mb analyzer). I'd rec buying one from china for +/-$500 incl laptop if you plan to keep this car. DAS will tell you under what cond the LTFT's are high..... is it part throttle lower load, or upper range? at idle? etc... until you know that you are pizzzing in the wind a bit.

3. Vac Leaks! If you found those lines unhooked..... you are on the right track. Keep digging around. Check hoses for cracks, splits, weak spots which can look normal when the car is off.... and then expose a leak when in action.

4. Check the connections to the MASS AIR METER up stream and down stream.

GL, once you solve this issue you will become mb tech master, and actually enjoy these little 'tasks' that owning an older star car brings.

 

I knew it was just a matter of time before you chimed in Jeff - you're quickly becoming the resident MBWorld MAF guru

 

Thanks Jeff (hope thats your name!) I had seen the star analyzer, seen a few cheap on fleabay (again lol)

Will see if I can track down the saem car in the company car park Monday and see what the heck that pipes supposed to be connected to.

Cheers - Tony

 

lol Kev - I don't know what is better..... have no problems with my car and know NOTHING about it..... or have alot of problems and slowly become a half-azzed mb tech : )


====
You can get it cheaper on ebay.... but here's a complete kit.

http://www.mbstarc3.com/mb-star-c3-i...rive-p-12.html

I have an extra t30 hDD with the star/das on it.... someone here can have it for free..... (you pay shipping)
It fires up about every 1/10 tries on my t30. I'm sure it's a software bug.

I consider my DAS Star kit essential to keeping my blown clk happy.
I would not have found out my autolevel zenon's were in-op w/o my own star/Das kit..... the dealer didn't tell me at my services these parts were out.... so I was able to point this out from my STAR setup.... and have them fix under warranty )

 

Solved the loose pipe, just hope it solves the problem
https://mbworld.org/forums/c-class-w...cuum-pipe.html

 

Well dude, all I can say is this - those of us that have problems always seem to fight through them and in turn, help fellow members. You're a prime example

 

Hey
How did you solve in the end the problem?
i have the same situation
my car c class 1.8 kompressor