Open wastegate at idle

[1gboost]

I bought this car with some issues that I've been trying to work out. I just got it back from the shop and noticed that my external wastegate is open even at idle. Not only can you hear the exhaust coming out of the dump tube when I put my hand down there I can feel the air hitting my hand. It's a smaller TiAL external wastegate, I don't know what the spring pressure is but that should be irrelevant considering it's open at idle. I have a truboost gauge on the car and it's set to crack at 8psi. I really don't know what would cause it to not seal at idle. When I first bought the car I had the wastegate off and looked it over and I could not (with my hand) push the valve up. I did not put air on it, the compressor I would use wasn't operational at the time.

I was just wondering if anyone has had a similar issue with an external and what was the cause.

 

[Revmoto]

Rebuild it if it is stuck open.

 

[1gboost]

"Rebuild" as in disassemble and reassemble? How is this going to fix my problem? I would rather want to know what the cause is. If it happens again I would know why. Or if I do this and something is bent or cracked isn't there a possibility it could work better at first and then repeat itself?
Back to my original question. Is there anyone who has had a similar problem? What was the cause?

 

[Revmoto]

"Rebuild" as in disassemble and reassemble? How is this going to fix my problem? I would rather want to know what the cause is. If it happens again I would know why. Or if I do this and something is bent or cracked isn't there a possibility it could work better at first and then repeat itself?
Back to my original question. Is there anyone who has had a similar problem? What was the cause?

Well the waste gate has a valve in it which is most likely seized. It could be bent but that is fairly uncommon. Tial should sell a rebuild kit. How many miles are on the waste gate? This shouldn't be a common problem once fixed.

 

[JusMX141]

The spring pressure is what holds the wastegate shut....if the diaphragm is torn, it simply wouldn't open or your boost control would be quite erratic.

Either the shaft of the valve is seized in the housing, the spring itself is broken, or you're missing the valve seat which fits into the base of the valve. I'm going with the latter seeing as I've never personally witnessed the first two events. Ever.

 

[1gboost]

I bought the car with the wastegate already installed. The previous owner wasn't completely done with the car so I would assume there shouldn't be too many miles on it unless he bought it used which I really doubt. My educated guess would say it's a fairly new wastegate with little miles at all. It's too bad you can't buy anything directly from TiAL. I'll see if I can find a rebuild kit.

 

[Gruff511]

Are you positive the fire ring is installed on the WG? i had the same issue when i forgot to put mines on. Also you should take it off and pressurize it to be sure its opening right.

 

[1gboost]

Well it still builds boost. The turbo is a 20g so it's a little lagy specially with an open wastegate but it will still hit boost within the 4-4.5 rpm's. The wastegate sounds like it's opening because it gets much louder in that rpm range but of course that could also just be because the car is running harder at that point too.

Are you positive the fire ring is installed on the WG? i had the same issue when i forgot to put mines on. Also you should take it off and pressurize it to be sure its opening right.

Fire ring? You mean valve seal right? Yes it is installed I just had that apart a couple weeks ago.

 

[Revmoto]

Project Import: Tial Wastegate Break Down Shaft Play - YouTube

This video gives you an idea of the piece you should be looking at.

 

[1gboost]

Thanks for the video.
With the spring still installed there isn't shaft play last time I had it off the car. Also, I don't have a problem with overboosting if anything I'm underboosting.

 

[92AWDHX40]

Worst case scenario, i would look for another one.

 

[1gboost]

I'm almost to that point. My entire turbo setup has been nothing but trouble since I got the car. The header is huge and sits practically up against my radiator and the car sometimes overheats on longer drives. This wastegate has been a pain as well.

 

[Revmoto]

I'm almost to that point. My entire turbo setup has been nothing but trouble since I got the car. The header is huge and sits practically up against my radiator and the car sometimes overheats on longer drives. This wastegate has been a pain as well.

When a waste gate is stuck open you get lag and when it is stuck closed it over boosted. Take it out and disassemble it. Only from there will you know what your problem is. It is either the valve or the diaphragm.