tonysemi

My 98 C43 has cut off on me a few times in the last month.. usually at a stoplight with my foot on the brakes at idle, just kinda dies. But starts back up fine, and runs great normally. Any ideas? Is this as simple as idle adjustment ( currently 6-700 RPM ) or something else? Thanks for your help

bzliteyear

I'm not mechanic and just guessing based on my prior experiences w/ E-class, but check the MAF(mass air flow?). It was about $350?

The wrong mechanic can end up fixing wrong things, and I think the idle is electronically adjusted by CPU so it's not like the cars of the 70's that you can tweak the RPM at idle.

Good luck.
PL

tonysemi

Thanks for your help

nathanphoenix

MAF sensor -- maybe, though I'd expect to see a more gradual degradation there.

Maybe check the fuel pump and fuel pump relay.

c55m8o

+1 for MAF or fuel pump/relay. I had failures of both. Here are my stories:

http://www.club202.com/forums/showth...&threadid=7908

http://www.club202.com/forums/showth...threadid=14781

tonysemi

Thanks for the help, im gonna check them out

ProjectC55

crank position sensors(CPS) go bad on these cars as well

tonysemi

its a gradual degragation, so thats more towards the MAF right? the crank sensor is either good or bad, theres no in between right?

thirifu

I accept with information: the idle is electronically adjusted by CPU so it's not like the cars of the 70's that you can tweak the RPM at idle.

benthebenzguy

camshaft position sensor on passenger side of the front of engine, this will cause car to just die part list for around $175 one torx bolt holds it in takes about 2 minutes to replace should have a code stored if you dont cycle key when the fault occurs.

crankshaft position sensor will usually get heat soak and car will crank and not start after sitting for a while after driving.


air mass will cause car to run poor and set check engine light for idle speed adaptation at limit left and right cylinder banks

fuel issues usually cause car to slowly die like its loosing power then just stops, electrical failures will just shut the car off instantly

tonysemi

Thanks!, the car just kinda dies when sitting at idle, mostly in the starbucks drive thru, LOL. No MIL or chk engine light.
No problem restarting.. and only shuts off a few (2-3) times a month. usually when its cold. So since I have no chk engine light.. should I start with the fuel filter? Thanks again for your time and knowledge

benthebenzguy

so fuel problems as i was saying will cause the car to slowly die, electrical issues will cause the car to just shut off instantly like you turned the key off.

a clogged fuel filter would cause a lack of power or a hard starting issue excessive cranking etc...


so if your car just dies in my experience i have found this to be the camshaft sensor, this sends a signal to ME (fuel injection brain) as to where the camshafts are only one sensor cause if it knows where one is the other better be in the right place. it uses this signal to determine spark, fuel etc...

early ME ecu's would not stored codes for crankshaft and camshaft signals if you cycled the key, so when you restart the car no code stored

also the computer does not turn on the CEL every time something acts up it wants to see a fault a certain number of times in a certain period of time

hope this helps a little more if you lived in los angeles i would give you hand

happy holidays

ben

tonysemi

Thanks Ben,
Great info about the CEL, I will change the fuel filter and camshaft sensor next service date. I never new it didnt store ALL codes. Again GREAT info! Im gonna call MB and order some parts.
Happy Holidays to you also.
Tony