Turbo - PeachParts Mercedes-Benz Forum

banjoread · #1 07-19-2006, 09:07 PM

Question. This new 300D I have seems not to be spending any time in the turbo range. My old one would hit that certain area where the turbo kicked in and suddenly I was flying. This new car has only 168,000 miles. Is it possible the turbo is simply pooped? It seems to idle a little low. could this have something to do with it. It never seems to get above 2500-3000 rpm (tach is busted)

also, on my old car, I used to be able to depress the accelorator and it would drop down a gear, into the turbo range, and I'd get a burst of power before returning to the higher gear. Not so on the new one, you're stuck in the gear you're in until you either brake, or move to the next gear.

Please note, the rubber hose leading from head cover to air filter leaks. Is any of this interrelated?

In need of some pickup!!

Thanks

blueranger · #2 07-19-2006, 09:12 PM

all turbos have a waiste gate where it discharges exhaust directly to the exhaust system...if this is proped open with carbon or if the system that opens and closes it has failed then this could be the issue... causing you not to experience boost.

mbzkid · #3 07-19-2006, 09:21 PM

This could be why your Turbo isn't providing any power. http://www.dieselgiant.com/mercedesaldaboostsystemservi.htm

The lack of kickdown (downshifting) could be from a bad kick down switch, which is located under the accelerator pedal. It could also be from other componets, but I don't know enough about your specific transmission.

blueranger · #4 07-19-2006, 09:32 PM

correct, often the feeling you think is boost is the kick down switch under the fuel pedal that causes the transmission to down shift a gear...

this switch is easily changed.... its electrical... and cost 25 bucks... so change that first and see what happens.....

i find it hard to believe anyone would feel any sort of kick in a mercedes diesel. Now in my turbo saab, the G forces often leave your face disfigured.

gsxr · #5 07-25-2006, 01:37 PM

The turbo should never feel like it's "kicking in". There should be decent power off-idle, which builds smoothly as the turbo pressure increases. If you got a kick in the pants, that meant you had low fuel delivery off-idle, which was compensated for as boost rose and the ALDA increased fuel. To correct this, you adjust the ALDA richer.

If you're not getting any power at all - no kick in the pants - the most likely cause is a plugged signal line from the intake manifold to the ALDA. Could be a plugged fitting at the manifold, a plugged "switchover" valve, or a cracked or broken tube/fitting. Less likely is a jammed-open wastegate, but it's possible.

It would help if you listed the year and model of your car, btw... in your signature, or profile, or both.