why 8 or 9psi now?? wg actuator problem

[ekizenbe]

so last night i was driving and my car was boosting fine to my mbc settting of 17 pounds. i got home all was fine. I wake up the next day and go for a drive, now for some reason my car only boost to 8 or 9 pounds. so i eliminate the mbc and run a line from the outlet of the turbo to the wg actuator. now im still getting the same number 8 or 9 psi. does this mean my wg actuator has gone bad???? i have suspected it was/is going bad but i have had no way to tell.

 

[iwannagofast89]

Do you have an air compressor?

 

[ekizenbe]

my friend does but its hard for me to go there as hes in iraq and i dont like dealing with the people at his house.

 

[tkelly27]

No that means your WG actuator is working properly. It could be that your MBC broke. It could also be a boost leak, however going from 17 to 9 with a boost leak, you'll probably know it by how awfully the car runs.

 

[ekizenbe]

the car runs perfect i drove it all day today. i guess i need to get a new boost controller for starters

 

[zero97tsi]

No that means your WG actuator is working properly. It could be that your MBC broke. It could also be a boost leak, however going from 17 to 9 with a boost leak, you'll probably know it by how awfully the car runs.

+1. I doubt it's a boost leak, because as was already pointed out with that big of a difference you would know. Since you havent filled out your profile I'm going to assume you're using your stock 14b, and the wg actuator is set to around ~9ish psi.

Open up you MBC and see if there is a piece of crud holding it open or something, or the spring may be broke.

 

[Inprogress]

From my experience when your wastegate diaphragm goes out it will max out the turbo, not run less boost.

 

[kenamond]

I agree with zero98tsi (and not just because he owns the best model DSM ever made ). Check your MBC. If you still have your BCS, you could reconnect that and see if you go back up to 12psi. That would be a pretty sure sign of an MBC issue.

The other possibility is something wrong with your BOV. If it opens prematurely and dumps boost back into the intake pipe, you'd not be able to build boost in the IM.

One final check THAT YOU NEED TO BE CAREFUL WITH is to disconnect the vaccuum line from the WGA and do a test run. As you give it the gas, watch your boost gauge and see if it goes past 15psi or so. Use the throttle to keep from overboosting. Because you've disconnected the WGA, it will not limit boost EVER, so you should only do this for the specific purpose of checking that you can build boost. Once you've done the test and have some result (boosted or still limited to 9psi), reconnect the WGA line before you forget. Don't want you destroying your motor because of this test.

 

[zero97tsi]

I agree with zero98tsi (and not just because he owns the best model DSM ever made ).

and yet you still got the year wrong in my name

As Kenamond said be very careful if you decide to test it with the open actuator. I tried doing this after my 14b install, and once you get above 10 Psi its starts to get very responsive. At 4 to 5k rpm the turbo spools very quickly. I'd hate to see another problem stem from trying to figure out this one.

 

[kenamond]

and yet you still got the year wrong in my name

Well, the 7 and 8 are right next to each other on the keyboard! I'm a touch-typer and screw up in very ironic ways.

As for the OP, I used a lot of boldface in my description of that, because it's very easy to overboost and do harm. So I'll add a 3rd warning. Do your test run somewhere where you don't go around turns or have traffic. Stare at the boost gauge as you give it the gas. Let off if/when it reaches 15psi. Then nurse it home at partial throttle so you don't overboost. Finally, park it and immediately reconnect the WGA vaccuum line (but don't burn yourself on any of the hot parts).

 

[ekizenbe]

ok guys ill try this tomorrow