C250 Acceleration
06-10-2023, 02:54 PM
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2012 c250
C250 Acceleration
Hey Y'all,
Just bought my first merc (C250 (2012) 1.8 turbo, 81k km driven) & its been having some trouble. Acceleration in lower revs seems sluggish. After about 3500 rpm it really gets going.
Clocked a standing 0-62 and best time I managed was 11 seconds in S mode.
Rolling start 10.3 seconds in S mode.
Just changed:
- air filter
- engine oil
- spark plugs
- gear sump packing
- transmission fluid
- transmission filter
Cleaned the cat out too. No errors on the scan tool, fuel pressure is around 5.5 bar in idle and uptown 6.9 bar when revving. Tach meter does blip immediately to high revs in a standing start, mid range pull is pretty strong. Mechanic checked it out and said there's low pressure in the rear fuel pump even though the scan tool shows 5.5 bar. MAF sensor is working and clean.
Need help.
Just bought my first merc (C250 (2012) 1.8 turbo, 81k km driven) & its been having some trouble. Acceleration in lower revs seems sluggish. After about 3500 rpm it really gets going.
Clocked a standing 0-62 and best time I managed was 11 seconds in S mode.
Rolling start 10.3 seconds in S mode.
Just changed:
- air filter
- engine oil
- spark plugs
- gear sump packing
- transmission fluid
- transmission filter
Cleaned the cat out too. No errors on the scan tool, fuel pressure is around 5.5 bar in idle and uptown 6.9 bar when revving. Tach meter does blip immediately to high revs in a standing start, mid range pull is pretty strong. Mechanic checked it out and said there's low pressure in the rear fuel pump even though the scan tool shows 5.5 bar. MAF sensor is working and clean.
Need help.
06-10-2023, 02:59 PM
#2
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2014 E63S; AMS 100 octane ecu tune; edok tcu tune; BB intakes; dyno tuned
Have you logged it for boost?
06-10-2023, 10:19 PM
#3
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That’s well off the acceptable mark. My 2013 Lux Sedan 106,000 miles (170,000 km) does rolling start 0-130 kph in less time.
Boost coming on at 3500 rpm is too low. Hard boost should be on at 1500 rpm or lower. Suspect malfunctioning waste gate, or maybe a big leak between turbo and intercooler.
Boost coming on at 3500 rpm is too low. Hard boost should be on at 1500 rpm or lower. Suspect malfunctioning waste gate, or maybe a big leak between turbo and intercooler.
06-10-2023, 11:00 PM
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2014 E63S; AMS 100 octane ecu tune; edok tcu tune; BB intakes; dyno tuned
That’s well off the acceptable mark. My 2013 Lux Sedan 106,000 miles (170,000 km) does rolling start 0-130 kph in less time.
Boost coming on at 3500 rpm is too low. Hard boost should be on at 1500 rpm or lower. Suspect malfunctioning waste gate, or maybe a big leak between turbo and intercooler.
Boost coming on at 3500 rpm is too low. Hard boost should be on at 1500 rpm or lower. Suspect malfunctioning waste gate, or maybe a big leak between turbo and intercooler.
07-02-2023, 12:54 PM
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Ran a torque pro scan and came across an open loop fault so it seems like the upstream o2 sensor needs to be replaced.
turbo actuator and exhaust gate seemed to be working fine. No issues in unburnt fuel either.
will get the sensor replaced, the intercooler connections reviewed and the intercooler serviced and report back.
turbo actuator and exhaust gate seemed to be working fine. No issues in unburnt fuel either.
will get the sensor replaced, the intercooler connections reviewed and the intercooler serviced and report back.
07-08-2023, 08:34 AM
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Odd discoveries with this car.
Removed the o2 sensor ahead of the CAT and go no check engine light. No error on the OBD2 sensor either. Seems like previous owner simply deleted it from the map maybe because the sensors weren’t working or whatever.
Now got to try to remap to base or change the ecu unit..
Removed the o2 sensor ahead of the CAT and go no check engine light. No error on the OBD2 sensor either. Seems like previous owner simply deleted it from the map maybe because the sensors weren’t working or whatever.
Now got to try to remap to base or change the ecu unit..
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07-08-2023, 12:02 PM
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So phew still no resolution.
Previous owner had:
- deleted the o2 sensors from the obd
- check engine light disabled
We put on a new ecu with freshly flashed software and the 0-60 times were the same. The o2 sensors started to show up too.
Other observations are that it’s SUPER slow off the line and in first gear.
Will get the waste gate metrics by next weekend intercooler service, do a couple of dyno runs and the car reflashed by the Mercedes reseller here
Previous owner had:
- deleted the o2 sensors from the obd
- check engine light disabled
We put on a new ecu with freshly flashed software and the 0-60 times were the same. The o2 sensors started to show up too.
Other observations are that it’s SUPER slow off the line and in first gear.
Will get the waste gate metrics by next weekend intercooler service, do a couple of dyno runs and the car reflashed by the Mercedes reseller here
