Huge loss of low end power when warm - OK when cold C200 Kompressor
#1
Junior Member
Thread Starter
Huge loss of low end power when warm - OK when cold C200 Kompressor
Hi, I've got a bad issue with the newly acquired C200 Kompressor model year 2000.
Low end power (stop lights, from standstill) is terrible. If I give anything more than a hair of throttle, the car does nothing for a while, then jerks and jack rabbits a while. Upon reaching RPM over say 1500-2000, and on gear 3,4,5,6 she runs smooth like it should.
Bad O2, MAF? Other sensor or gremlins?
What I've checked so far
- New air filter, didn't solve it
- Fixed a vacuum leak, didn't solve it
I cleared the fault codes of the engine and drove around a bit. No error code reappeared.
When the car is cold, just starting it and driving away the first minute, the power at low end seems OK. Much better than warm anyway.
The Torque Light app mentioned there was a fault in the feedback of the O2-sensor.
Inputs are very welcome. Fuel consumption seems OK:ish. Slight smell from exhaust. So fuel mixture is very likely not perfect.
Low end power (stop lights, from standstill) is terrible. If I give anything more than a hair of throttle, the car does nothing for a while, then jerks and jack rabbits a while. Upon reaching RPM over say 1500-2000, and on gear 3,4,5,6 she runs smooth like it should.
Bad O2, MAF? Other sensor or gremlins?
What I've checked so far
- New air filter, didn't solve it
- Fixed a vacuum leak, didn't solve it
I cleared the fault codes of the engine and drove around a bit. No error code reappeared.
When the car is cold, just starting it and driving away the first minute, the power at low end seems OK. Much better than warm anyway.
The Torque Light app mentioned there was a fault in the feedback of the O2-sensor.
Inputs are very welcome. Fuel consumption seems OK:ish. Slight smell from exhaust. So fuel mixture is very likely not perfect.
#2
Super Member
Also, what is your long term trim?
Post a screen-shot of graphs of the long term trim, main 02, rpm, MAF.
#5
Junior Member
Thread Starter
I was able to write down a few data from a torque.
At idle and fully warm engine.
Maf 4.5 g/s
Idle 740 rpm/s cirka
O2 sensor 1 and 2 both cirkled between 0.1-0.8 volts
After driving some more I got the CEL and code P0170. Fuel trim adjustment outside of spec.
I think the maf may be aftermarket. So will check that during the week.
I also found a vacuum hose with a yellow end which is not connected to anything. Standing in front of the engine it is located to the left of the center of the car. Quite close to the front. Should that be or where should it be connected to?
Maf 4.5
At idle and fully warm engine.
Maf 4.5 g/s
Idle 740 rpm/s cirka
O2 sensor 1 and 2 both cirkled between 0.1-0.8 volts
After driving some more I got the CEL and code P0170. Fuel trim adjustment outside of spec.
I think the maf may be aftermarket. So will check that during the week.
I also found a vacuum hose with a yellow end which is not connected to anything. Standing in front of the engine it is located to the left of the center of the car. Quite close to the front. Should that be or where should it be connected to?
Maf 4.5
#6
Junior Member
Thread Starter
Timing advance cirkled between -10 and 0.
16.6 inch/hg was the intake vacuum at idle.
Fuel trim one bank one 1x1=-40. All other fuel trims were at -30 so figured they were not used.
Sorry no graphs and actual photo. Hope it is possible to draw conclusions anyway.
16.6 inch/hg was the intake vacuum at idle.
Fuel trim one bank one 1x1=-40. All other fuel trims were at -30 so figured they were not used.
Sorry no graphs and actual photo. Hope it is possible to draw conclusions anyway.
#7
Super Member
What was the long term percentage?
Take a picture of the vacuum line. On the left/passenger-side, iirc, there's a vacuum line that goes to the ?"EGR" bypass? valve that is on the front left of the engine. Iirc, that valve actually controls if fresh air (from the baffle) is sent into the exhaust during startup - to reduce cold start emissions.
Take a picture of the vacuum line. On the left/passenger-side, iirc, there's a vacuum line that goes to the ?"EGR" bypass? valve that is on the front left of the engine. Iirc, that valve actually controls if fresh air (from the baffle) is sent into the exhaust during startup - to reduce cold start emissions.
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#8
Junior Member
Thread Starter
What was the long term percentage?
Take a picture of the vacuum line. On the left/passenger-side, iirc, there's a vacuum line that goes to the ?"EGR" bypass? valve that is on the front left of the engine. Iirc, that valve actually controls if fresh air (from the baffle) is sent into the exhaust during startup - to reduce cold start emissions.
Take a picture of the vacuum line. On the left/passenger-side, iirc, there's a vacuum line that goes to the ?"EGR" bypass? valve that is on the front left of the engine. Iirc, that valve actually controls if fresh air (from the baffle) is sent into the exhaust during startup - to reduce cold start emissions.
OK, yeah the car could have had an EGR-delete. I'll snap a photo during the week. Only prob. is the hood isn't openable right now, so a workshop will take a look.
#9
Super Member
So, that may be the raw value?
The engine should be around +/- 0-4%. Imho, anything over 10% is often bad.
I'd say between 5% and 10% is maybe okay - but there may also be a problem.
If there are engine mods, then the engine may likely be +5% to +10%. The long-term trim would likely be higher at high loads and higher rpm.
The long-term trim is likely either a 2-dimensional or 3-dimensional table based on rpm, load, etc. I don't know what MB uses for either the MB M111 or M271 engines.
#10
Junior Member
Thread Starter
I doubt that it's 40 percent. Iirc, the max is ~+/- 15%-20%.
So, that may be the raw value?
The engine should be around +/- 0-4%. Imho, anything over 10% is often bad.
I'd say between 5% and 10% is maybe okay - but there may also be a problem.
If there are engine mods, then the engine may likely be +5% to +10%. The long-term trim would likely be higher at high loads and higher rpm.
The long-term trim is likely either a 2-dimensional or 3-dimensional table based on rpm, load, etc. I don't know what MB uses for either the MB M111 or M271 engines.
So, that may be the raw value?
The engine should be around +/- 0-4%. Imho, anything over 10% is often bad.
I'd say between 5% and 10% is maybe okay - but there may also be a problem.
If there are engine mods, then the engine may likely be +5% to +10%. The long-term trim would likely be higher at high loads and higher rpm.
The long-term trim is likely either a 2-dimensional or 3-dimensional table based on rpm, load, etc. I don't know what MB uses for either the MB M111 or M271 engines.
Well, the last data point frozen in the app is showing -16.4%, I'll verify with the car at idle again. Let's hope it actually isn't that high.
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#11
Super Moderator
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What is your fuel consumption like? Not sure what OK ish means, Any change? Remember that it is critical that your temperature sensor is good. Seems your car is OK in open loop mixture enriched but not warmed up closed loop with the MAF in circuit. It is critical that the ECU is fed the correct engine temperature for proper fuel trim. It is also critical that the MAF is sound.
Last edited by Glyn M Ruck; 11-09-2016 at 01:22 PM.
#12
Junior Member
Thread Starter
Thanks for the reply Glyn. I've ordered a new Bosch maf yesterday. The one in the engine bay looked suspicious from day 1. The arrow on the intake tube and the maf point towards each other. That can't be correct. Also it ks like an aftermarket unit. I've replaced a couple of mafs in other cars before.
I also had the same thoughtime open loop is ok but not closed. Which temp sensor do you have in mind? Intake air or coolant?
I also had the same thoughtime open loop is ok but not closed. Which temp sensor do you have in mind? Intake air or coolant?
#14
Super Moderator
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Thanks for the reply Glyn. I've ordered a new Bosch maf yesterday. The one in the engine bay looked suspicious from day 1. The arrow on the intake tube and the maf point towards each other. That can't be correct. Also it ks like an aftermarket unit. I've replaced a couple of mafs in other cars before.
I also had the same thoughtime open loop is ok but not closed. Which temp sensor do you have in mind? Intake air or coolant?
I also had the same thoughtime open loop is ok but not closed. Which temp sensor do you have in mind? Intake air or coolant?
#15
MBWorld Fanatic!
NOT IAT!
Last edited by insame1; 11-10-2016 at 08:46 AM.