Is my wastegate actuator bad?

[DJ23GSX]

Im have an intermittent boost fall off issue. I can build 17psi of boost but sometimes it will fall off to 13psi by redline. With my hallman pro boost controller set to 14psi the car held perfect boost all the way to redline. Only when I upped the boost on the hallman this issue started. My mods at the moment are a stock 14b (minimal shaft play) with a 7cm turbine housing, tubular o2 housing, thermal catback (stock dpipe and cat) 560's and a safc. When I say sometimes i mean it only falls as low as 13psi once in a while. Most of the time it will hit 17psi then only fall to about 15psi. I have one small boost leak at the tb shaft seals but it isn't horrible. I can pressurize the system to 20psi and it takes a good 25 seconds or more to bleed down to 0. I pulled off the actuator to test it and at roughly 5psi the arm starts to move slowly till it fully opens. At 10psi to the actuator it slams wide open. I'm also wondering if the bigger flapper on the 7cm turbine housing along with the tubular o2 housing could be hurting me especially on the stock dpip and cat.

 

[itworks]

On all internal wastegates there will be an intial spike and a hold. On my srt 4 i spike 19psi but hold 15. Once you get an external wastegate or a solid boost controller there wont be as much spike as a weak internal wastegate. Also check for boost leaks as u said if it take 25 seconds to bleed down to 0 from 20 psi then at about every .5 to 1.5 seconds you lose 1 psi of boost. When wot shifting your in it for a good 3 to 4 seconds i.e. 3 to 4 psi of boost

 

[DJ23GSX]

On all internal wastegates there will be an intial spike and a hold. On my srt 4 i spike 19psi but hold 15. Once you get an external wastegate or a solid boost controller there wont be as much spike as a weak internal wastegate. Also check for boost leaks as u said if it take 25 seconds to bleed down to 0 from 20 psi then at about every .5 to 1.5 seconds you lose 1 psi of boost. When wot shifting your in it for a good 3 to 4 seconds i.e. 3 to 4 psi of boost

I agree about the psi a wastegate should hold and thats why I'm questioning mine. I've run many dsm's up to 18psi on the stock internal gate with the same hallman pro boost controller with no spike or boost lose issues like this. I've run up to 20psi on the internal gate on my old 16g setup without a problem but that car had full 3" turbo back exhaust which I'm sure helped keeping the turbo spooled in the high rpms. I've also had much bigger boost leaks without this issue as well. These two reasons alone are what made me start thinking the wastegate actuator may be going bad. I'm not sure my boost leak would cause this problem only sometimes. I would think if a constant leak in the system were the cause it would happen all the time no? I'm starting to wonder if the stock dpipe and cat are choking the turbo and causing the wastegate flapper door to blow open due to a weak actuator. I think my next step is to try and shim the actuator and if it seems to help then I can assume its shot.

 

[dsmdeliveryboy]

Sounds like normal spike and drop to me on a 14b with a 7cm housing, I'm having problems getting the turbo to stop creeping.. I have similar mods as you, just a few more things like a fmic etc.. If your not hitting fuel cut I wouldn't worry too much about it, you can try shimming the wastegate actuator with like 2-3 washers and see how that helps.

 

[DJ23GSX]

Sounds like normal spike and drop to me on a 14b with a 7cm housing, I'm having problems getting the turbo to stop creeping.. I have similar mods as you, just a few more things like a fmic etc.. If your not hitting fuel cut I wouldn't worry too much about it, you can try shimming the wastegate actuator with like 2-3 washers and see how that helps.

It cant be "normal" spike and drop cause it only does this occasionally. I can deal with say a 2psi drop but on some pulls I'm losing a full 4psi by redline. What makes me think something is bad is that fact that it changes and isn't consistent. Sometimes it drops a lot sometimes it drops very little.

 

[deviousgst]

It cant be "normal" spike and drop cause it only does this occasionally. I can deal with say a 2psi drop but on some pulls I'm losing a full 4psi by redline. What makes me think something is bad is that fact that it changes and isn't consistent. Sometimes it drops a lot sometimes it drops very little.

....

have you figured your problem out? i'm having the same exact problem..and it jst started yesterday. i use to hold 20psi all the way to redline on my ported16g and full 3in exhaust..but all of a sudden now i boost 20psi and bleeds down to about 16psi..and even before when i'd open my ecut out i'd boost 25psi and hold it till redline..now it boosts 25psi and falls to 18psi..

 

[DJ23GSX]

....

have you figured your problem out? i'm having the same exact problem..and it jst started yesterday. i use to hold 20psi all the way to redline on my ported16g and full 3in exhaust..but all of a sudden now i boost 20psi and bleeds down to about 16psi..and even before when i'd open my ecut out i'd boost 25psi and hold it till redline..now it boosts 25psi and falls to 18psi..

I may have figured out my problem. I did more testing of the wastegate while it was off the car and on a few occasions when the actuator arm came out it was a little cockeyed and when I released the pressure it didn't close all the way. This would explain why it only happens to me sometimes. My actuator was pretty rusty so I cleaned up the rod and gave it a little shot of penetrating oil at the base of the rod and it seems to move much smoother now. When I have the time I'll take it out for a good rip and see if its all better. I'll be sure to post back with an update.

 

[DJ23GSX]

SOLVED:


I found my problem. It wan't the wastegate actuator at all. The T fitting for my boost guage was cracked. I replaced it and now I'm holding a rock solid 16psi all the way to redline with no spikes or drops at all

 

[JusMX141]

On all internal wastegates there will be an intial spike and a hold.

....when you're attempting to run more than double the actuator's spring pressure. Under normal circumstances, internal wastegates are inexpensive and reliable- hell even the new BW EFR turbos are internally-gated.

 

[DJ23GSX]

....when you're attempting to run more than double the actuator's spring pressure. Under normal circumstances, internal wastegates are inexpensive and reliable- hell even the new BW EFR turbos are internally-gated.

I agree.


After figuring out my problem I actually wasn't loosing boost pressure at all its just that the fitting that is feeding my boost gauge was leaking causing the gauge to read inaccurate boost levels. Even when the problem was at its worse I still couldn't feel the car fall on its face at all. She was pulling good all the way to redline even though the boost gauge was falling to 10psi by 5k rpms.

 

[bq509]

I just swapped the 2g plastic bov to a 1g uncrushed and now all of the sudden my car spikes to 30 psi with the mbc turned ALL the way down and on a t25 turbo. When i boosted it blew the vaccum line off that my aftermarket boost gauge is connected to. I still don't know why its doing this when all i swapped was the bov. Everyone is saying its. my wastegate

 

[bryanwheat]

An easy way to test the wastegate would be to run the boost source line directly to the wastegate and leave the boost controller off and go for a drive. It should go to around 10 psi.