C250 TD Flat Spot

[reflexboy]

Morning all-My C280 is just perfect, but my friend owns a C250 Turbodiesel, 1998, R Reg Facelift. He seems to have a bit of a flat spot around 1800-2000 rpm regardless of which gear he is in. Has anyone else experienced this on a C250 TD? Or, does anyone have any idea what may be causing this and/or the remedy? Any helf greatly appreciated-Thanks.

 

[mstar01]

hi

does anybody have an idea about this?

 

[Dieselman]

You need to check the boost pressure. If the pressure rises quickly then the turbo and wastegate are Ok.
It could be something simple like the wastegate actuator is split or the MAP sensor is faulty.

 

[reflexboy]

Sorry, forgot to post the update! My mate has now resolved this by blocking off a pipe that MB fitted as a device to help with emissions, but later reliased it wasnt needed. A steel ball bearing was used to block off the pipe...not sure which one mind

 

[Dieselman]

EGR valve.

 

[reflexboy]

Thats the one...The EGR valve.....Thanks Mr/Sir Dieselman.

 

[GazCaff]

Does blocking off the EGR valve pipe make a big difference? I remember doing it on a Vento TDI a few years ago and I have to say it made no perceptable difference...

 

[garymac]

The EGR valve on my C250 TD auto was causing problems too. If you used kickdown then backed off the pedal then reapplied the accelerator the car was very unresponsive, lumpy and smokey. Blocked the EGR valve off and it has been a dream ever since. The MPG also improved dramatically....

 

[GazCaff]

The EGR valve on my C250 TD auto was causing problems too. If you used kickdown then backed off the pedal then reapplied the accelerator the car was very unresponsive, lumpy and smokey. Blocked the EGR valve off and it has been a dream ever since. The MPG also improved dramatically....

well, I've done the dirty deed and popped a screw into te EGR actuator pipe. I'll see how she runs tomorrow.

 

[Oom]

Which pipe is this exactly? I would also like to give this a try. What does EGR stand for?

 

[mstar01]

exactly wot i thought is this a MB secret, can it do any harm long term?

 

[Dieselman]

Blocking the EGR valve will not harm the engine, in fact it will be beneficial.
Exhaust Gas Recirculation is a rather crude method of reducing Nox at lean running conditions.
It recycles exhaust gas which is inert, to deplete the amount of oxygen in the airstream. This reduces Nox as there is less oxygen to burn.

 

[KLP 92]

Blocking the EGR valve will not harm the engine, in fact it will be beneficial.
Exhaust Gas Recirculation is a rather crude method of reducing Nox at lean running conditions.
It recycles exhaust gas which is inert, to deplete the amount of oxygen in the airstream. This reduces Nox as there is less oxygen to burn.

Finally got round to blocking mine off today. Noticed a difference in the performance and fuel economy! I used to find after being stuck in traffic for long durations the car used to feel slower than before, well not anymore!

 

[GazCaff]

Finally got round to blocking mine off today. Noticed a difference in the performance and fuel economy! I used to find after being stuck in traffic for long durations the car used to feel slower than before, well not anymore!

I have to report the same thing as well. I can't comment on the economy yet but the car is a lot more responsive, it certainly seems to have reduced turbo lag when on the move.

 

[mstar01]

must be worth a try, whats the best way to block it off? i might get a garage to do it, as i dnt know wot i am doing seems like a "techy" job

 

[KLP 92]

30 sec job, disconnected the pipe and put a screw in it! Would take less time but i dropped the screw! You can use a ball bearing but i didn't have one to hand.

 

[KLP 92]

I have to report the same thing as well. I can't comment on the economy yet but the car is a lot more responsive, it certainly seems to have reduced turbo lag when on the move.

Well i've been on the road all day and i've done over 100 miles and its made a difference. Will find out how much when i fill it up next time.

 

[GazCaff]

must be worth a try, whats the best way to block it off? i might get a garage to do it, as i dnt know wot i am doing seems like a "techy" job

The ideal method is to insert a ballbering of suitable size into the egr actuator pipe (the small pipe coming off the top of it) as this method doesn't tend to throw up a fault code with the ecu. As I didn't have a ballbearing I used a mushroom headed screw for the same result.

 

[Oom]

Which pipe is this exactly? I would also like to give this a try. What does EGR stand for?

^^ What that says! My local dealership has no clue... no wonder they break something everytime they try fix something!

 

[twice]

Does the blocking of the EGR valve has any affect on a non-turbo, '94 250D engine? Does it worth a try?