STD Tuning Engine Turbo help needed (1990 300D)

Turbo help needed (1990 300D)

Turbo help needed (1990 300D)

 
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amcya
Naturally-aspirated

8
11-23-2010, 08:08 PM #1
Motor runs great and so does the turbo...when it wants to. The boost is intermittent. I will accelerate up to speed, turbo responds quickly, 15-17 lbs boost. I will start to cruise, boost will drop and won't come back up. Maybe the next couple of times I will accelerate I will have only 1-2 lbs or 0. Sometimes i will be in the middle of accelerating and the boost will jump up or drop off. It's like a switch just turns off. Does anyone know where I should start looking? Can I go with a manual controller and ditch these solenoids? Thanks.

1990 300D 2.5 Turbo 5-speed...stock for the moment
amcya
11-23-2010, 08:08 PM #1

Motor runs great and so does the turbo...when it wants to. The boost is intermittent. I will accelerate up to speed, turbo responds quickly, 15-17 lbs boost. I will start to cruise, boost will drop and won't come back up. Maybe the next couple of times I will accelerate I will have only 1-2 lbs or 0. Sometimes i will be in the middle of accelerating and the boost will jump up or drop off. It's like a switch just turns off. Does anyone know where I should start looking? Can I go with a manual controller and ditch these solenoids? Thanks.


1990 300D 2.5 Turbo 5-speed...stock for the moment

willbhere4u
Six in a row make her go!

2,507
11-23-2010, 08:14 PM #2
First check the turbo shaft for play!

1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
willbhere4u
11-23-2010, 08:14 PM #2

First check the turbo shaft for play!


1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running

tomnik
Holset

587
11-24-2010, 12:20 AM #3
also check the overload protection valve in the boost line.
Or just bypass it for testing only to be sure.

Tom
tomnik
11-24-2010, 12:20 AM #3

also check the overload protection valve in the boost line.
Or just bypass it for testing only to be sure.

Tom

E300TSC
Turbo-Supercharged

321
11-24-2010, 06:21 AM #4
Yeah, isn't there some sort of boost "switchover" valve in these cars that controls the wastegate?

1998 MB E300 - 194,000 miles. Current/future mods: 7.5mm pump elements, Holset HX40 Turbo feeding Eaton M90 supercharger through custom fabbed intake system. Aeroturbine muffler, scratch-built 4" stainless exhaust. EGR eliminated, ECM recalibrated, modified rack position feedback circuit. Porterfield RS brake pads, Bilstein sport shocks, VDO EGT, oil and boost gauges.

2000 Ford F250 - 150,000 miles. Current/future mods: DP Tuner 3 map chip, scratch-built high flow intake, high output IDM, open circuit fuel system, ball bearing turbo, South Bend full metal clutch, slotted and drilled rotors. Autometer Sport Comp EGT and boost gauges.
E300TSC
11-24-2010, 06:21 AM #4

Yeah, isn't there some sort of boost "switchover" valve in these cars that controls the wastegate?


1998 MB E300 - 194,000 miles. Current/future mods: 7.5mm pump elements, Holset HX40 Turbo feeding Eaton M90 supercharger through custom fabbed intake system. Aeroturbine muffler, scratch-built 4" stainless exhaust. EGR eliminated, ECM recalibrated, modified rack position feedback circuit. Porterfield RS brake pads, Bilstein sport shocks, VDO EGT, oil and boost gauges.

2000 Ford F250 - 150,000 miles. Current/future mods: DP Tuner 3 map chip, scratch-built high flow intake, high output IDM, open circuit fuel system, ball bearing turbo, South Bend full metal clutch, slotted and drilled rotors. Autometer Sport Comp EGT and boost gauges.

amcya
Naturally-aspirated

8
11-24-2010, 10:30 AM #5
I clearly think I have narrowed it down to a vacuum or switch issue. I don't think there is a problem with the turbo, wastegate or actuator.

Where is the overload protection valve? I see the three valves by the airbox but they only have vacuum reference.

1990 300D 2.5 Turbo 5-speed...stock for the moment
amcya
11-24-2010, 10:30 AM #5

I clearly think I have narrowed it down to a vacuum or switch issue. I don't think there is a problem with the turbo, wastegate or actuator.

Where is the overload protection valve? I see the three valves by the airbox but they only have vacuum reference.


1990 300D 2.5 Turbo 5-speed...stock for the moment

tomnik
Holset

587
11-24-2010, 10:40 AM #6
follow the line connected to the ALDA.
The valve should be on the driver side somewhere in the engine compartment.
Electrically the valve is connected to a pressure switch which might be in the intake manifold. Over pressure there makes the valve swich on and vent the ALDA (disconnect boost to ALDA).

Tom
tomnik
11-24-2010, 10:40 AM #6

follow the line connected to the ALDA.
The valve should be on the driver side somewhere in the engine compartment.
Electrically the valve is connected to a pressure switch which might be in the intake manifold. Over pressure there makes the valve swich on and vent the ALDA (disconnect boost to ALDA).

Tom

 
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