97 C36, Poor Acceleration When Warm
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Joined: Oct 2018
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1997 AMG C36
97 C36, Poor Acceleration When Warm
Does anyone else find their C36 feels very snappy and rapid when it's cold, but it's much more sluggish when it's warm? And by warm I only mean in the region of 80 Celsius.
Here's a video I just took, 0-60 seems to come in at around 7 seconds although it's a bit awkward with the angle of the camera not being straight in front of the needle. Because of where I live I can't really do a 0-60 before the engine has warmed up by the time I've got to somewhere I can safely do it, but I'm confident it would be much faster at cold. At cold it feels like I can just blip the throttle and it pulls hard and spins the wheels. When warm it often doesn't spin them at all even when floored, as you can see in this video the ASR light doesn't go off at all.
This is me flooring the pedal from a dead stop:
There's also always been this raspy rattly sound that isn't present on any other 0-60 videos I've found.
Things done:
Camshaft sensor (made it MUCH better but it's definitely still there)
MAF sensor
Fuel rail regulator was leaking, fixed, but metal swarf was found in the fuel rail and the cause hasn't been found...
K40 OVR Relay changed (for a second hand one...)
Holding the pedal down for 5 seconds reset thing
It's a 97 C36 from Japan. Thanks!
Here's a video I just took, 0-60 seems to come in at around 7 seconds although it's a bit awkward with the angle of the camera not being straight in front of the needle. Because of where I live I can't really do a 0-60 before the engine has warmed up by the time I've got to somewhere I can safely do it, but I'm confident it would be much faster at cold. At cold it feels like I can just blip the throttle and it pulls hard and spins the wheels. When warm it often doesn't spin them at all even when floored, as you can see in this video the ASR light doesn't go off at all.
This is me flooring the pedal from a dead stop:
There's also always been this raspy rattly sound that isn't present on any other 0-60 videos I've found.
Things done:
Camshaft sensor (made it MUCH better but it's definitely still there)
MAF sensor
Fuel rail regulator was leaking, fixed, but metal swarf was found in the fuel rail and the cause hasn't been found...
K40 OVR Relay changed (for a second hand one...)
Holding the pedal down for 5 seconds reset thing
It's a 97 C36 from Japan. Thanks!
Thread Starter
Newbie
Joined: Oct 2018
Posts: 9
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1997 AMG C36
I’ve come across quite a few posts from c36 owners saying they get consistent acceleration at all temperatures and RPMs that there must be something I can do to improve things? Also seen plenty of complaints about worsening performance at higher temperatures, though mine doesn’t really go over 80 - doesn’t seem very high?
Ive seen some stuff about using a 79 degrees or lower thermostat, but then also some stuff saying that this just means the coolant will start flowing a little earlier and won’t actually reduce temperatures once it would have been flowing anyway on the original thermostat.
Also some stuff about the ECU switching from closed loop to open loop once the engine reaches temperature. Could there be something wrong with open loop, like bad O2 sensor data, causing the fuel/air ratio to give less performance than in closed loop mode?
Ive seen some stuff about using a 79 degrees or lower thermostat, but then also some stuff saying that this just means the coolant will start flowing a little earlier and won’t actually reduce temperatures once it would have been flowing anyway on the original thermostat.
Also some stuff about the ECU switching from closed loop to open loop once the engine reaches temperature. Could there be something wrong with open loop, like bad O2 sensor data, causing the fuel/air ratio to give less performance than in closed loop mode?
Thread Starter
Newbie
Joined: Oct 2018
Posts: 9
Likes: 0
1997 AMG C36
Also forgot to mention - there’s a big, sudden boost in acceleration at about 4000rpm. I understand that this is the point where the resonance flap switches and it’s common to have a bit of a flat spot before this, but not all the way from 0 to 4000rpm?
