C43 low on power, poor cold start, off-idle hessitation
Thread Starter
Senior Member
Joined: Feb 2017
Posts: 392
Likes: 9
From: Australia
W202 C43 1999
if your car drives slow like grandpa using a walker?
it could be clogged injectors not giving enuff fuel?
have you tried with a bottle of which brew Motul cleaner poured in your tank when you're low on fuel below 30 litres?
low on fuel gives you a higher cleaning concentrate.
maybe you have a vacuum leak somewhere giving you issues?
it could be clogged injectors not giving enuff fuel?
have you tried with a bottle of which brew Motul cleaner poured in your tank when you're low on fuel below 30 litres?
low on fuel gives you a higher cleaning concentrate.
maybe you have a vacuum leak somewhere giving you issues?
it has been checked for vacuum leaks and none were found, but im putting in a brand new OEM intake manifold and two new Bosch knock sensors. The actuator on the manifold is working, but i dont know if the flaps are.
MBWorld Fanatic!
Joined: Sep 2007
Posts: 4,566
Likes: 421
05 c55 silver, 98 Imperial Red C43
Ok just to let you guys know.
Before giving other people advice online on what to put through their car engines, please make sure you did your research and that youve done it your self.
Just coz you read somewhere that it works, doesnt mean its safe.
Ive talked to certified mercedes techs and they dont recommend running any of that stuff through your engine.
Before giving other people advice online on what to put through their car engines, please make sure you did your research and that youve done it your self.
Just coz you read somewhere that it works, doesnt mean its safe.
Ive talked to certified mercedes techs and they dont recommend running any of that stuff through your engine.
Thread Starter
Senior Member
Joined: Feb 2017
Posts: 392
Likes: 9
From: Australia
W202 C43 1999
Ok just to let you guys know.
Before giving other people advice online on what to put through their car engines, please make sure you did your research and that youve done it your self.
Just coz you read somewhere that it works, doesnt mean its safe.
Ive talked to certified mercedes techs and they dont recommend running any of that stuff through your engine.
Before giving other people advice online on what to put through their car engines, please make sure you did your research and that youve done it your self.
Just coz you read somewhere that it works, doesnt mean its safe.
Ive talked to certified mercedes techs and they dont recommend running any of that stuff through your engine.
Thread Starter
Senior Member
Joined: Feb 2017
Posts: 392
Likes: 9
From: Australia
W202 C43 1999
Ok, the issue remains.
New intake manifold made little to no difference, knock sensors were both replaced at this time.
I recently replaced the spark plugs, 14 of them were fine, but the 2 plugs in cyl 7 were quite worn, the center electrode was worn away badly.
What would cause this?
There is minor smoke from the exhaust at wide open throttle, but i cant tell the colour. This could be oil, but the plugs did not show signs of burning excess oil.
Replacing the plugs made very little difference.
There is no water in the oil.
Oil is Mobil 1 0w40 at the moment.
New intake manifold made little to no difference, knock sensors were both replaced at this time.
I recently replaced the spark plugs, 14 of them were fine, but the 2 plugs in cyl 7 were quite worn, the center electrode was worn away badly.
What would cause this?
There is minor smoke from the exhaust at wide open throttle, but i cant tell the colour. This could be oil, but the plugs did not show signs of burning excess oil.
Replacing the plugs made very little difference.
There is no water in the oil.
Oil is Mobil 1 0w40 at the moment.
Senior Member
Joined: Feb 2017
Posts: 384
Likes: 41
From: West Palm Beach, FL
'99 C43, '88 560SL
Ok, the issue remains.
New intake manifold made little to no difference, knock sensors were both replaced at this time.
I recently replaced the spark plugs, 14 of them were fine, but the 2 plugs in cyl 7 were quite worn, the center electrode was worn away badly.
What would cause this?
There is minor smoke from the exhaust at wide open throttle, but i cant tell the colour. This could be oil, but the plugs did not show signs of burning excess oil.
Replacing the plugs made very little difference.
There is no water in the oil.
Oil is Mobil 1 0w40 at the moment.
New intake manifold made little to no difference, knock sensors were both replaced at this time.
I recently replaced the spark plugs, 14 of them were fine, but the 2 plugs in cyl 7 were quite worn, the center electrode was worn away badly.
What would cause this?
There is minor smoke from the exhaust at wide open throttle, but i cant tell the colour. This could be oil, but the plugs did not show signs of burning excess oil.
Replacing the plugs made very little difference.
There is no water in the oil.
Oil is Mobil 1 0w40 at the moment.
Thread Starter
Senior Member
Joined: Feb 2017
Posts: 392
Likes: 9
From: Australia
W202 C43 1999
wow, so many parts replaced chasing this problem. Not that this would apply to you but there was a time where i would hit the gas and the engine would not accelerate like it should. I went through changing so many fuel/air parts only to find the potentiometer that was connected to gas pedal was loose! I cant wait to see what your actual problem was
The throttle potentiometer was replaced a couple years ago and that made a BIG difference at the time, the previous one was original and when i tested it in my E55 it was sluggish in there too.
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
MBWorld Fanatic!
Joined: Aug 2006
Posts: 7,053
Likes: 398
From: A.D., U.A.E
2000 (W202 C200) & 2000 (W202 C55)
What throttle potentiometer..!?!, do you mean TB sensor (black one front of brake booster)..?,,
you can relearn the TB by, switch on the key (position 2) without starting, keep the key (position 2), go and be closer the TB, till you hear TB clicking,
then switch the key off, for 10 seconds, TB should be relearned,,
no need to waste more time & $$$, try to diagnose the car, codes will narrow the issue..!
-;ZAYED;-
you can relearn the TB by, switch on the key (position 2) without starting, keep the key (position 2), go and be closer the TB, till you hear TB clicking,
then switch the key off, for 10 seconds, TB should be relearned,,
no need to waste more time & $$$, try to diagnose the car, codes will narrow the issue..!
-;ZAYED;-
MBWorld Fanatic!
Joined: Aug 2006
Posts: 7,053
Likes: 398
From: A.D., U.A.E
2000 (W202 C200) & 2000 (W202 C55)
What throttle potentiometer..!?!, do you mean TB sensor (black one front of brake booster)..?,,
you can relearn the TB by switch on the key (position 2) without starting, keep the key (position 2), go and be closer the TB, till you hear TB clicking,
then switch the key off, for 10 seconds, TB should be relearned,,
no need to waste more time & $$$, try to diagnose the car, codes will narrow the issue..!
-;ZAYED;-
you can relearn the TB by switch on the key (position 2) without starting, keep the key (position 2), go and be closer the TB, till you hear TB clicking,
then switch the key off, for 10 seconds, TB should be relearned,,
no need to waste more time & $$$, try to diagnose the car, codes will narrow the issue..!
-;ZAYED;-
Thread Starter
Senior Member
Joined: Feb 2017
Posts: 392
Likes: 9
From: Australia
W202 C43 1999
What throttle potentiometer..!?!, do you mean TB sensor (black one front of brake booster)..?,,
you can relearn the TB by switch on the key (position 2) without starting, keep the key (position 2), go and be closer the TB, till you hear TB clicking,
then switch the key off, for 10 seconds, TB should be relearned,,
no need to waste more time & $$$, try to diagnose the car, codes will narrow the issue..!
-;ZAYED;-
you can relearn the TB by switch on the key (position 2) without starting, keep the key (position 2), go and be closer the TB, till you hear TB clicking,
then switch the key off, for 10 seconds, TB should be relearned,,
no need to waste more time & $$$, try to diagnose the car, codes will narrow the issue..!
-;ZAYED;-
The pedal position sensor is what i am refering to, and is mounted on the left side infront of the ECU, on the E55 it is on the right side infront of the brake booster.
i will try what you said about throttle learn. Thanks
Junior Member
Joined: Feb 2018
Posts: 17
Likes: 5
From: Austin Tx
1998 C43 AMG, 2000 Audi S4, 2001 Audi S4, 2007 Subaru Forester XT
I've had to replace my Accelerator Pedal Sensor (took 10 minutes), and 1 coil so far on my C43. The Pedal sensor cost me 120 bucks from FCP Euro, and the part arrived with a logo etched off. The MB part is like 700 dollars, and the FCP Euro part number pulls up as Hella on other sites. I ended up pulling a few coils from the junk yard and solved my misfire in Cylinder 4. I had a super rough idle and the car would begin to sputter between 500-1500 RPM when in reverse before swapping the coil. It took the car a few cycles to reveal a cylinder misfire. Seriously no codes? Has the car been scanned at an independent shop or dealer yet?
Thread Starter
Senior Member
Joined: Feb 2017
Posts: 392
Likes: 9
From: Australia
W202 C43 1999
Thread Starter
Senior Member
Joined: Feb 2017
Posts: 392
Likes: 9
From: Australia
W202 C43 1999
I've had to replace my Accelerator Pedal Sensor (took 10 minutes), and 1 coil so far on my C43. The Pedal sensor cost me 120 bucks from FCP Euro, and the part arrived with a logo etched off. The MB part is like 700 dollars, and the FCP Euro part number pulls up as Hella on other sites. I ended up pulling a few coils from the junk yard and solved my misfire in Cylinder 4. I had a super rough idle and the car would begin to sputter between 500-1500 RPM when in reverse before swapping the coil. It took the car a few cycles to reveal a cylinder misfire. Seriously no codes? Has the car been scanned at an independent shop or dealer yet?
MBWorld Fanatic!
Joined: Aug 2006
Posts: 7,053
Likes: 398
From: A.D., U.A.E
2000 (W202 C200) & 2000 (W202 C55)
Are you sure about that..?!,
as i know; even with E55, this sensor always in driver side, ..!?!
it should be on passenger (LEFT) side with RHD only, isn't..?!!?
-;ZAYED;-
as i know; even with E55, this sensor always in driver side, ..!?!
it should be on passenger (LEFT) side with RHD only, isn't..?!!?
-;ZAYED;-
Thread Starter
Senior Member
Joined: Feb 2017
Posts: 392
Likes: 9
From: Australia
W202 C43 1999
The C43 i have here is exactly where it is in your photo, and ive not seen one with it mounted anywhere else.
There is no question it is on the passenger side on an RHD C43, the duo valve is on the opposite side is the same place.
Thread Starter
Senior Member
Joined: Feb 2017
Posts: 392
Likes: 9
From: Australia
W202 C43 1999
MBWorld Fanatic!
Joined: Aug 2006
Posts: 7,053
Likes: 398
From: A.D., U.A.E
2000 (W202 C200) & 2000 (W202 C55)
Hope no vacuum leaks, or more air in fuel system..!,,
do you know if fuel filter is good, or not clogged, this could interrupted the FPR..!,,
did you check all these..?!?
-;ZAYED;-
do you know if fuel filter is good, or not clogged, this could interrupted the FPR..!,,
did you check all these..?!?
-;ZAYED;-
Thread Starter
Senior Member
Joined: Feb 2017
Posts: 392
Likes: 9
From: Australia
W202 C43 1999
yep, filter is 3 months old and MANN brand, pump is 12 months old and genuine pierburg, injectors were all replaced and tested.
Thread Starter
Senior Member
Joined: Feb 2017
Posts: 392
Likes: 9
From: Australia
W202 C43 1999
Id imagine it works simular to GM traction control on the Delphi PCM the Corvettes had where there is spark retarding and throttle plate closure to reduce power, so obviously when the power is let back on it comes in very hard and the way i reckon it should be at all times when you floor it.
Sometimes its like when you floor it its more like 70% throttle, but after traction control has cut in its like full instant 100%.
MBWorld Fanatic!
Joined: Aug 2006
Posts: 7,053
Likes: 398
From: A.D., U.A.E
2000 (W202 C200) & 2000 (W202 C55)
I had bad hesitation about year ago, replaced everything, no check engine light, no codes,
after about two weeks, i discovered that fuel cap seal was sooooo bad, that builds much air in whole fuel system, and purge valve & vent valve were badly clogged,
replaced "fuel cap/tank vent valve/purge valve", hesitation went away, everything settled,,
can't assure you have the same issue, but have to share this, it may helps..
-;ZAYED;-
after about two weeks, i discovered that fuel cap seal was sooooo bad, that builds much air in whole fuel system, and purge valve & vent valve were badly clogged,
replaced "fuel cap/tank vent valve/purge valve", hesitation went away, everything settled,,
can't assure you have the same issue, but have to share this, it may helps..
-;ZAYED;-
Thread Starter
Senior Member
Joined: Feb 2017
Posts: 392
Likes: 9
From: Australia
W202 C43 1999
I had bad hesitation about year ago, replaced everything, no check engine light, no codes,
after about two weeks, i discovered that fuel cap seal was sooooo bad, that builds much air in whole fuel system, and purge valve & vent valve were badly clogged,
replaced "fuel cap/tank vent valve/purge valve", hesitation went away, everything settled,,
can't assure you have the same issue, but have to share this, it may helps..
-;ZAYED;-
after about two weeks, i discovered that fuel cap seal was sooooo bad, that builds much air in whole fuel system, and purge valve & vent valve were badly clogged,
replaced "fuel cap/tank vent valve/purge valve", hesitation went away, everything settled,,
can't assure you have the same issue, but have to share this, it may helps..
-;ZAYED;-
