Dear members,
I am Tomba and new here. I need someone opinion about a car that is in our workshop which we can not solve the problem from.
I is a S class from 2006/04 with 260.000km/163.000 miles.
Histroy:
- Owner bought the car and let it inspected by a MB dealership, MAF housing and some other bits were the main things that need to be replaced. MAFs replaced and the owner let the car have a service for engine and gearbox (engine oil + filter, air filters, gearbox filter and oil).
- Customer let his car to be chiptuned and decides after a few weeks to test top speed. The car doesn't go faster than 200km/h (125mph) and gets into limp mode. Turns off the car and proceeds driving without problems.
- After a few weeks he tries the same, same error but the error seems to come up more often.
- Other workshop replaces the electric EGR valve due to EGR related error codes. No succes. Intake manifold gets replaced with the swirl flaps inside. Again no succes.
- Then the car come to our shop with the following error description:
Once you try to accelerate the car feels terrible slow and it seems to interrupt the power for short terms and some black clouds of smoke come from the exhaust. Read out error codes with Autocom:
- 2598 - EGR position left, wrong signal, intermit.
- 2385 - EGR valve regulation, to much air, intermit.
- 2696 - Left exhaust pressure sensor, pressure to high, permanent
- 2592 - Position sensor turbo actuator, wrong signal, permanent
It seems that the EGR flow is to low (air mass measured from MAFs to high).
Turbocharger variable mechanism sticks in open position. With a little hand help you can get it down and no error appears.
During live data the left and right bank pressure sensors give the same values. > ~1040hPa on ignition on, engine off and ~2000hPa with idle running engine (variable mechanism of the T/C in closed position).
When I rev the engine at standstill car I can hear a typical sound near ~1600rpm which I can not locate. Also around 2000-2500rpm the turbo sound is like boosting/not boosting/boosting/not boosting. When I push the accelerator pedal more down around 3000rpm it gets worse and when I flat the accelerator pedal it starts to give the typcical diesel knock and lots of smoke. When releasing the accelerator pedal is sounds like the T/C is in surge and the engine starts to stall or run rough for a few seconds and then idles perfectly.
Checked the following things:
- EGR channels towards and from the EGR valve> they might be clogged and not allowing enough flow. All good.
- Pressurised the entrace of the turbo and top off the intercouler outlet hose to check for air leaks (a leak might cause high MAF readings). Not 100% certain since I could not pop off the hose correctly but there seem to be no leaks >removed the lower panels to het access to the intercooler and pipes for better looking.
- Checked the shut off valve in front of the intake manifold. With a removed intercooler outlet hose I can see that the valve is closing. This must be (I think) due to the lack of EGR flow. When closing the valve which is placed before the EGR pipe entrace you get more flow from the EGR. Even disconnected the electric plug. Doesn't make any difference.
- Measured injector returnflow to see if a faulty injector could be the problem. Bank 1 or right (drivers side in UK) seems ok, left bank seems plausible. injector (middle) seems to stop leaking (no injection) before others do. Pictures attached. This is from idle to slowly 3000rpm and full throttle.
- Finally loaded in the original software to exclude the chiptuning could be the cause. No difference.
I am out since most thinks are already replaced (by another workshop). Do any of you have a clue what is going on?
I appriciate your help!
Best regards,
Tomba
I am Tomba and new here. I need someone opinion about a car that is in our workshop which we can not solve the problem from.
I is a S class from 2006/04 with 260.000km/163.000 miles.
Histroy:
- Owner bought the car and let it inspected by a MB dealership, MAF housing and some other bits were the main things that need to be replaced. MAFs replaced and the owner let the car have a service for engine and gearbox (engine oil + filter, air filters, gearbox filter and oil).
- Customer let his car to be chiptuned and decides after a few weeks to test top speed. The car doesn't go faster than 200km/h (125mph) and gets into limp mode. Turns off the car and proceeds driving without problems.
- After a few weeks he tries the same, same error but the error seems to come up more often.
- Other workshop replaces the electric EGR valve due to EGR related error codes. No succes. Intake manifold gets replaced with the swirl flaps inside. Again no succes.
- Then the car come to our shop with the following error description:
Once you try to accelerate the car feels terrible slow and it seems to interrupt the power for short terms and some black clouds of smoke come from the exhaust. Read out error codes with Autocom:
- 2598 - EGR position left, wrong signal, intermit.
- 2385 - EGR valve regulation, to much air, intermit.
- 2696 - Left exhaust pressure sensor, pressure to high, permanent
- 2592 - Position sensor turbo actuator, wrong signal, permanent
It seems that the EGR flow is to low (air mass measured from MAFs to high).
Turbocharger variable mechanism sticks in open position. With a little hand help you can get it down and no error appears.
During live data the left and right bank pressure sensors give the same values. > ~1040hPa on ignition on, engine off and ~2000hPa with idle running engine (variable mechanism of the T/C in closed position).
When I rev the engine at standstill car I can hear a typical sound near ~1600rpm which I can not locate. Also around 2000-2500rpm the turbo sound is like boosting/not boosting/boosting/not boosting. When I push the accelerator pedal more down around 3000rpm it gets worse and when I flat the accelerator pedal it starts to give the typcical diesel knock and lots of smoke. When releasing the accelerator pedal is sounds like the T/C is in surge and the engine starts to stall or run rough for a few seconds and then idles perfectly.
Checked the following things:
- EGR channels towards and from the EGR valve> they might be clogged and not allowing enough flow. All good.
- Pressurised the entrace of the turbo and top off the intercouler outlet hose to check for air leaks (a leak might cause high MAF readings). Not 100% certain since I could not pop off the hose correctly but there seem to be no leaks >removed the lower panels to het access to the intercooler and pipes for better looking.
- Checked the shut off valve in front of the intake manifold. With a removed intercooler outlet hose I can see that the valve is closing. This must be (I think) due to the lack of EGR flow. When closing the valve which is placed before the EGR pipe entrace you get more flow from the EGR. Even disconnected the electric plug. Doesn't make any difference.
- Measured injector returnflow to see if a faulty injector could be the problem. Bank 1 or right (drivers side in UK) seems ok, left bank seems plausible. injector (middle) seems to stop leaking (no injection) before others do. Pictures attached. This is from idle to slowly 3000rpm and full throttle.
- Finally loaded in the original software to exclude the chiptuning could be the cause. No difference.
I am out since most thinks are already replaced (by another workshop). Do any of you have a clue what is going on?
I appriciate your help!
Best regards,
Tomba
