Scoupe wastegate solenoid

[Rob Muller]

I have a 1993 Scoupe turbo. The wastegate solenoid is either broken or the hoses are connected incorrectly. When the solenoid is not energized, the air that comes from the turbo is routed to the wastegate resulting in low turbo pressure.

This is how the solenoid looks like:
http://members.home.nl/rob.muller/solenoid.jpg

Hose number 1 is connected to the air intake, hose number 2 to the pressure side of the turbo and number 3 is connected to the wastegate. Is this correct? The solenoid seems to work fine, that is why I suspect that the hoses are not correctly connected. It seems far more logical if hose 1 is connected to the turbo, hose 2 to the wastegate and hose 3 to the air intake. In this situation when the solenoid is not energized any pressure in the hose to the wastegate actuator will bleed off to the air intake. When energized, the air pressure from the turbo is routed to the wastegate. Is this how it should be connected?

Maybe someone with a Scoupe turbo can have a look to see how the hoses are connected? The solenoid is located under the battery. You can see how the hoses are connected without removing any parts from your car.

The online service manual (thanks Hyundai, this has been really helpful several times) is not correctly describing my car in this particular area. In the manual, the solenoid is not connected to the pressure side of the turbo but to the manifold. This might be explained by model differences between the cars from the US and the Netherlands. http://www.hmaservice.com/webtech/iindex.asp?id=7717

Thanks in advance.

Rob

 

[Rob Muller]

This is how the solenoid looks like:
http://members.home.nl/rob.muller/solenoid.jpg .... It seems far more logical if hose 1 is connected to the turbo, hose 2 to the wastegate and hose 3 to the air intake. In this situation when

I have tried connecting the hoses to the wastegate solenoid in this way. There is no obvious overboost, the last boost led does not light up, and there is a lot more boost. It is a different car when rpm is above 2500. So there is reason to belief the hoses are connected correctly now.

There is one problem: at half throttle there is more boost and power than at wide open throttle. What can cause this? Can this be the ECM operating the wastegate solenoid to prevent overboosting. I would expect the boost to stay the same instead of decreasing if this would be the case though. Does the ECM measure the manifold pressure in order to decide to operate the wastegate or is this open loop? Maybe the ECM detects knocking and operates the wastegate?

Sometimes the check engine light turns on: boost too low. Maybe the pressure is not released fast enough from the wastegate actuator hose when the ECM pulses the wastegate solenoid?

This car has been driven real slow for 5 years, I am not sure if this has anything to do with the problem but it might be worth to mention. The wastegate is not stuck. The engine does not stutter or jerk at wide open throttle.

Rob