My other 300D just started having no power and shifting hard. I have installed the convervsion kit on my other 1992. There is something that is puzzling me about this car. When I pull the rubber boot off the intake port that runs down to the ALDA, I cleaned out the fitting that was totally stopped up and thought I had found the problem. But here is the weird thing. My other car produces pressure and blows air out of that intake port, the car Im having trouble with is sucking air back into the intake through that port, what is going on. I know that it shouldn't be sucking air back thru there and should instead be pressure coming out. Anyone have any ideas?

Maybe put a gauge on it. Until the turbo kicks in on my car there is a slight vacuum there.

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Cheers!
Scott McPhee

1987 300D

You need a supercharger or a cranked down VNT to pressurize the manifold at idle.

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

the more throttle I give this car the more vacuum it produces. I am not using a gauge but Im just placing my finger over the hole the more throttle the more it wants to pull into it. Now I put a vac. gauge on it and with giving it some throttle it was over making over 10 in of vac.

Air filter and mass air flow meter (if the car has one) could be a cause.

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Present
1987 300SDL
1991 300SL
1990 560SEL
2001 ML320

Past
1969 200D 1979-82
1983 300SD 1984-85
1972 250C 1982-02
1995 S350 2011
1997 S320 2012

are you checking the actual port out of the manifold, or are you measuring the vacuum connector that is on the port going to the blue saucer?

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

but yeah... a plugged air filter or a closed flap on the filter box could cause vacuum for sure...

and you'd need to be under a load to produce boost I'd think...

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Ok thanks guys. I'm checking right off the intake at the fitting that the rubber connector that goes done to Alda. I will check the filter and the maf today and report back.

It was indeed a faulty air filter lid that was causing my issue