Rail Head

I have a boost pattern of like 11-6-11 and it was taking its good ole time getting back to 11 at like about 5500 to 6000 rpm. This made me suspect the pre-contol operation.

To trouble shoot, I checked connections etc. and then finally dicsonnected the vacuum line on the pre-control actuator and used a vacuum pump to see if the actuator moved. Unfortunately the I was unable to create any vacuum so I assume the actuator diaphram is blown.

If the actuator is blown, can it be replaced or rebuilt without taking the entire turbos off or engine out? Please say yes. If no what's the best way to get parts?

Also, if it is blown I assume the vacuum tank will be emptied everytime the pre-control solenoid is opened. Will this impact other functions requiring the vacuum? Whould it be wise to plug the vacuum line or can the pre-control solenoid just be electrically disconnected?

Any help would be appreciated.

Thanks,

Doug

Rail Head

Being that I haven't recieved any feedback makes me wonder if this would be better suited in the Tech section. Again any feedback to confirm my findings or advice is appreciated.

KZ1

the reason it takes a "good ole" time top get back is becasue it is still in twin operation. it is suppose to do that, drop below about 3k and it will go back to primary mode.

11-6-11 is not necesarliy a bad TPC actuator, could be selnoid, wiring, etc. it woudl help if I knew what mods you have as well. First off, get a vacuum pump. However, the actuator does not operate on vacuum, but on pressure. All you need is some fittings and a bicycle pump(don't pump too much, heheh) plug other side of actuator(or flip selenoid) adn make sure it doesn't leak, etc.

Luckily selenoid is right up front, so it is easy to get too. if actual actuator operates okay, move there. do allt eh test, etc.

Also, if you motor or turbos are tired, or it is really hot outside, you may get les prespool as turbo don't have enough to vent to create enough boost. What gear did you do the test it?

Rail Head

Being that I haven't recieved any feedback makes me wonder if this would be better suited in the Tech section. Again any feedback to confirm my findings or advice is appreciated.

Rail Head

Thanks for the reply KZ1.

First of all my car is an automatic. Sorry. I ran the boost test in both 2nd and in 3rd with the hold on for full lock up. In second the it dropped a little less and recovered faster than 3rd.

As for as a vacuum pump goes, I have one. If not mistaken the actuator is operated by pressure directly from the primary turbo and vacuum controled by the pre-control solenoid. I disconnected the vacuum side and the vacuum pumped sucked air and showed nothing on the gauge.

Right or wrong about the actuator being blown, can it be changed without removal of entire turbo or engine???

Rail Head

^

7-sins

Try testing the solenoid since it is right on top of the engine(easy to get to). If that doesnt work then start tracing it's lines. Also check to see the connectors are in the right place one of those two solenoids should have a white dot, this should match up with the connector that has a white dot. The Turbo Pre-Control and the Wastegate actuators rairly fail.

Rail Head

I disconnected the electrical connection to the pre-control solenoid and the boost pattern is now like 7-11, Maybe the actuator moved permanently and both turbos share exhaust 100% of the time?

What do you guys think?

Doug