Anyone have a view on whether it is harmful to the engine to tap the accelerator lighty when starting the car? This is only because lately occasionally I find the benz a little wobbly on the start and giving it a little tap helps smooth the starting. 90% car starts strongly and confidently, but 10% have had it struggle in the last month and on 2 occasionally within that it has spurted then gone quiet. Given the age, and with no particular pattern to the problem, remembering that with this model year the aircon is set to always come ON when the car is started (regardless of previous setting before switching the car off). Thus I feel the engine being taxed a little more than usual hence sometimes the revs drops very quickly after starting and one can hear the engine gulp! Any advise what could be causing this or should I just let it rest and continue with the light accel tapping? Thanks heaps guys. Any questions pls ask.
When starting, is it ok to tap the accel lightly?
jeffreyli86
Active Member
Never knew the aircon comes on automatically. Used to drive a C280 and it never did that (I'm so Hong Kong so it may be different?)... However, I've had a Bimmer 328 cabrio that does that...
Anyway, I had a similar problem to yours a week or so ago.. I took it as a sign that the spark plugs are going... This is because I didn't pay much attention to the rough start and the spark plugs went when I was in a traffic jam... So I had to keep the engine running for at least 30mins on 3 cylinders...
After changing the spark plugs.. It was fine... Started confidently everytime...
Anyway, I had a similar problem to yours a week or so ago.. I took it as a sign that the spark plugs are going... This is because I didn't pay much attention to the rough start and the spark plugs went when I was in a traffic jam... So I had to keep the engine running for at least 30mins on 3 cylinders...
After changing the spark plugs.. It was fine... Started confidently everytime...
guydewdney
MB Enthusiast
with the cold weather lately, it could just be that the battery is showing its age...
is it like this just in the mornings - or is it seemingly random?
is it like this just in the mornings - or is it seemingly random?
jimmy
MB Enthusiast
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With modern fuel injection and ECU's there should be no need to blip the throttle, must be a problem somewhere else.
As a sideline, never blip the throttle before stopping the engine. See loads of people doing it, it is very bad for the engine.
As a sideline, never blip the throttle before stopping the engine. See loads of people doing it, it is very bad for the engine.
Hi Klee, my 1997 C180 has the same problem and mine happens all the time I start cold. Once hot, it starts alright. Even 1 hour ago I got it to start, but it did hiccup after the first revs and nearly dies usually, sometimes it recovers and runs ok. Today I had to step on the accel. to keep it running. There is an unusual whining sound(medium freq) for a few seconds, not really loud, sounds like dry metal spinning against other metal sound. I get this type of sound with a louder whine in my 1992 Camry which has rubber timing belt. After the sound dies off, the motor runs for a few more minutes at a fast pace before it settles down to a 800rpm or so idle. The earlier faster rpm run must be the automatic choke.
Cclass guy
Member
I think I read somewhere it's not so good to do so. Though I'm curious about what models had AC start when cranking the engine. Mine is '98 W202 facelift and I don't have a clue if it does or not 
Dave Bailey
Active Member
hocky said:
Hope this isn't the case for you, but I had a similar noise to the one you describe. It turned out to be the starter motor. It made the noise for some time, but eventually gave up and left me stranded early one morning. £160 exchange for the motor itself, but a £500 bill from the stealer for the complete job. And that was after a vigorous complaint exercise. They originally wanted £700. It might be worth getting it checked out just in case.
Thanks guys. I migrated to Sydney taking the car along and so it isn't the cold in the morning affecting it. It is pretty random although someone else put a thought into my mind - they said apparently it does say in the mb manual that tapping may be required when hot starting as opposed to cold starting. I have yet to check this out in the manual. So I thought back and yes I do remember once it didn't start first time whilst engine was still hot. Since posting I try not to tap anymore just to see the freq and pattern. I noted comment on not tapping accel before switching off. I will check spark plugs at some point.
I know for a fact that 1997 models have the option to memorize the prev EC (aircon button) setting. But on my 1996 the EC light is always OFF when the car starts regardless of prev setting ie aircon is ON always, and I have to push it again to switch OFF. (Any 1996 owners pls write in and confirm as I've not heard the same from anyone!) The prev owner always thought this was a strange decision on MBs part but I suppose the logic could be our cars are at the premium end and so comfort came first? I have noticed on the 1997 model (sis in laws) that even if the aircon is meant to come on when starting the aircon clutch 'thunk' doesn't kick in immediately but after the engine has 'settled'. (Better)
hocky, does your clunking noise increase in freq and volume if you tap the accel? If not engine related it could be the same symptoms I had which turned out to be a worn out aircon clutch which was the first sign of the aircon compressor calling it a day after 9 years, which I just replaced a month ago. The other thing is don't forget the MBs don't have a cam belt but a cam chain and chains make more noises than a belt!
I know for a fact that 1997 models have the option to memorize the prev EC (aircon button) setting. But on my 1996 the EC light is always OFF when the car starts regardless of prev setting ie aircon is ON always, and I have to push it again to switch OFF. (Any 1996 owners pls write in and confirm as I've not heard the same from anyone!) The prev owner always thought this was a strange decision on MBs part but I suppose the logic could be our cars are at the premium end and so comfort came first? I have noticed on the 1997 model (sis in laws) that even if the aircon is meant to come on when starting the aircon clutch 'thunk' doesn't kick in immediately but after the engine has 'settled'. (Better)
hocky, does your clunking noise increase in freq and volume if you tap the accel? If not engine related it could be the same symptoms I had which turned out to be a worn out aircon clutch which was the first sign of the aircon compressor calling it a day after 9 years, which I just replaced a month ago. The other thing is don't forget the MBs don't have a cam belt but a cam chain and chains make more noises than a belt!
I just chked the MB owner's manual and on page 14 "Starting and stopping petrol engine" it does actually say under the Starting section:
"Turn key in steering lock fully to the right. Do not depress the accelerator. Once engine is running release the key.
Engine at operating temperature:
If the engine does not start within approx 4 seconds, fully depress accelerator and continue attempt at starting. Once the engine is running, ease off the accelerator.
At very high coolant temperatures, depress the accelerator slowly during starting."
Did you people know that??
Also on the subject of aircon my owner's manual page 24 states "The air conditioner is always operational. The system does not cool the air if economy mode EC is selected." My manual's copy deadline is dated 09/05/1995.
"Turn key in steering lock fully to the right. Do not depress the accelerator. Once engine is running release the key.
Engine at operating temperature:
If the engine does not start within approx 4 seconds, fully depress accelerator and continue attempt at starting. Once the engine is running, ease off the accelerator.
At very high coolant temperatures, depress the accelerator slowly during starting."
Did you people know that??
Also on the subject of aircon my owner's manual page 24 states "The air conditioner is always operational. The system does not cool the air if economy mode EC is selected." My manual's copy deadline is dated 09/05/1995.
Last edited:
rees_A
Banned
I have climate in my 1996 C class, Air con always remembers setting when turned back on.ie. EC button is on if was on when turned engine off and vice versa
Thanks Rees. I don't have automatic climate control on mine just the manual thumb wheels, air flow, air distribution dials and the EC button. But in the manual page 28 re Automatic Climate Control it also states the same "The automatic climate control is always operational." Anyone has the same setup like my 1996 C220 please write and tell if yours operates the same? That is aircon always ON when starting the car regardless of prev setting before stopping the engine.
Also can anyone confirm the operation of the "recirculate air" function - mine always switches over from recirculating to outside air after 5 minutes. I can't seem to get it to stay in recirculate mode for longer than that. I want it to because in Sydney its HOT and this is the right way to keep the interior cool without taxing the compressor/engine. If I read correct the manual states it should only switch over to outside air after 30 minutes if outside temperature is above 5 C. And btw I also noticed on my instrument cluster, the numeric readout section below the fuel gauge is always blank when the manual says it should display the Outside temperature - should this be true of my 1996 C220 model or is it an optional feature? (If defective this could be what's causing my recirculate air feature to function abnormally)
Also can anyone confirm the operation of the "recirculate air" function - mine always switches over from recirculating to outside air after 5 minutes. I can't seem to get it to stay in recirculate mode for longer than that. I want it to because in Sydney its HOT and this is the right way to keep the interior cool without taxing the compressor/engine. If I read correct the manual states it should only switch over to outside air after 30 minutes if outside temperature is above 5 C. And btw I also noticed on my instrument cluster, the numeric readout section below the fuel gauge is always blank when the manual says it should display the Outside temperature - should this be true of my 1996 C220 model or is it an optional feature? (If defective this could be what's causing my recirculate air feature to function abnormally)
