MAF or MAS testing for a C180 Auto

Sonetuk

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Jun 1, 2005
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I have a C180 Auto 1997 with a suspect gear box fault.
How can i can test the MAF or MAS before striping the gear box.
The star plug test is not conclusive as it list's many possibilities.
Does any one have any ideals. :confused:
 

Gunny

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1999 CLK 320 elegance 2001 C200 Kompessor Avantgarde
If you take the car to an independant who has the kit to read the fault codes it can be done in a matter of minutes.

Gunny
 

silverarrow

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Mar 19, 2004
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many start to fail with out fault code showing i have a used one which works fine i was given this when a friend sold his car send me part number you can buy it or try it and see if it works why pay for pointless diagnostic codes that will not tell you it has failed mafs tend to fail just in spec but cause all sorts of problems
do not try electrical cleaner it does not work

i have had audis and mercs all with maf problems 4 cars in total send me a pm with your part number if same then its up to you new £200 at least
 
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Sonetuk

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MAF readings for C180 auto

Hallo am tying to take my readings but am stack.
My Mastech multimeter has 2 connectors. I suppose one will be for input and other out put.

I understand the MAF has 5 connecters and only uses 4

Connector 2 for input 12V (I suppose this is from the car battery
connecter 3 for the Gnd ( What is this could it be ground or earth)
connecter 4 for 5V ( I suppose this is an in put too)
connecter 5 for the out put.

Where would i connecter the 2 wire or pins from my DMM
 

230K

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Hi

Between 4 & 3

230K
 
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Sonetuk

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These are my MAF readings.
Readings were taken when car was in Neutral with winter settings (W). Would (S) make a difference in these readings

REV output V
700 1.47
1000 1.49
1500 1.63
2000 1.74
2500 1.8
3000 1.9
3500 2.14
3700 3.18 It was not able to reach 4000 revs. It kind of cut off and would only bounce between 3500 and 3700 at full throttle
4000
4500
5000

Driving with the MAF disconnected did not make a difference. The gears jerk while shifting from reverse to drive or vice versa.
Could there be a fault in the gear box impacting the MAF.

Sonetuk
 

Copiertech

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May 21, 2005
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faulty maf affects gearbox as the gearbox ecu does not know how much load the engine is under. reduced rev limit is because car is in "limp-home" mode. sounds like the maf is gone. you can try to clean it with brake cleaner, which is less aggressive than carb cleaner but only as a testing measure, it wont last any time. mafs on any car are a common failure. vacuuming out the airbox when changing the air filter and only using high quality standard type air filters prolong their life, oiled k&n type filters are bad for them.
 

Steve_Perry

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Copiertech said:
...reduced rev limit is because car is in "limp-home" mode...
Are you referring to why Sonetuk could not rev past 4000rpm? It is because the ECU limits the engine to approx 4k for protection when the gearbox is in neutral or park. This is normal and not an indication of a fault. If you're limited to 4000 rpm whilst moving then it is an indication of a fault of some kind.

S.
 
Last edited:

Copiertech

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oh aye. i dont know what i was thinking. limp home mode does reduce rev limit though to prevent engine damage. i didnt read the first post properly as i was just out of bed.
 

230K

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09 E320 cdi Sport Estate, 98 E300TD Estate, 99 SL 500
Sonetuk said:
These are my MAF readings.
Readings were taken when car was in Neutral with winter settings (W). Would (S) make a difference in these readings

REV output V
700 1.47
1000 1.49
1500 1.63
2000 1.74
2500 1.8
3000 1.9
3500 2.14
3700 3.18 It was not able to reach 4000 revs. It kind of cut off and would only bounce between 3500 and 3700 at full throttle
4000
4500
5000

Driving with the MAF disconnected did not make a difference. The gears jerk while shifting from reverse to drive or vice versa.
Could there be a fault in the gear box impacting the MAF.

Sonetuk

You need to test the MAF loaded as well as unloaded. Stick pins through the 2 wires you need and keep the MAF connected and bring the meter into the car and have an assistant read the readings.
http://mbclub.co.uk/forums/showthread.php?t=9279&page=1&pp=15

230K
 
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Sonetuk

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thanks 230k but what do you mean by loaded or unloaded ?. :confused:
I had the multimeter wires connected to connector 5 via a pin and the body to get my readings.
Was this loaded or unloaded.
Where should i connector the wires for the next test

thanks
 

230K

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09 E320 cdi Sport Estate, 98 E300TD Estate, 99 SL 500
Hi

Loaded & Unloaded.
Drive the car to get the loaded readings have an assistant with you to note the voltage readings.
Car in neutral will get you the unloaded readings although she will only rev to about 4000rpm like this.
Connections you have seem correct.

230K
 

Gunny

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Location
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1999 CLK 320 elegance 2001 C200 Kompessor Avantgarde
MAF Failure

:( :(

All this talk about MAF's failing etc etc, I think mine has done the journey.

Took the w203 c 200 Komp out on Sunday & it was flat as a fart no pick up no thottle response no top end - really slow.

I have disconnected the battery & will reconnect tonight , no sure if it will make any differance as there are no fault codes coming up on the in car read out, but I once did this on a car that had intermitant thottle problems & it cured it.
If it doesnt do the trick, looks like a trip down to the local independant, unless any of you guys have any thoughts.

Gunny
 
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Sonetuk

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Replacing MAF while car is Limp home mode.

I have cleaned the MAF with brake cleaner and even changed the air filter but readings are still low.
It's clearer the stealer is about to make more money. :mad:

Is there any thing i have to do before or after replacing the MAF.
Will error codes auto clear or will the ECU auto discover the new maf. :confused:


cheers

Sonetuk
 

Gunny

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Messages
124
Location
Guisborough Cleveland
Car
1999 CLK 320 elegance 2001 C200 Kompessor Avantgarde
Sonetuk said:
I have cleaned the MAF with brake cleaner and even changed the air filter but readings are still low.
It's clearer the stealer is about to make more money. :mad:

Is there any thing i have to do before or after replacing the MAF.
Will error codes auto clear or will the ECU auto discover the new maf. :confused:


cheers

Sonetuk

Try europarts they are a lot cheaper than the stealer - just been quoted £198.00 for mine

Gunny
 

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