here is my original post explaining the problem:

hey i just made a post about this, not realizing this was already made. mine was called troubleshoot: boost falling off. same thing. long road trip in the rain this last weekend. coming from a toll booth first and second pulled hard, but third gear stopped at 5K rpms. this happened two times. then today after drying out for two days it didnt feel like it was boosting up right like it normally does at about 3K rpms. i have had it for a month and have just about 2k miles on it. anyone come to a resolution with this or contact a dealer??? i think ill contact mine. PM me with info, thanks..



figured once it dried out it would shape up but it didnt. been running funny all week, not boosting up as powerful as it did before. anyway i took it in today to dealer. they checked it out and on my receipt it said new wastegate ordered, selenoid or something like that wategate. so guess it wasnt me being paranoid and they are gonna call me when it part comes in. part and installation are covered so it costs me nothing. just letting you guys know if you experience the same problem.

jeff

 

It certainly sounds like a wastegate type of issue so that seems like a logical thing to look at. Hope that fixes it for you and the other people who have similar issues!

 

thats why i posted what they said about mine, hopefully it will work to correct the problem. everyone else who has this problem at least now has a direction to look in i guess.....

 

bump since this might be important

 

Yes, another guy was reporting similar problems, and his dealer was changing out solenoids, and basically having difficulties finding the issue. Not sure if he ever got his problems resolved or not? The truth is that unless you really understand how turbo engines work, you can chase your tail for a long time. Unfortunately MMC techs may fall into the category of the un-informed.

The solenoid is the factory boost control (FBC) which receives voltage signals from the ECU, and basically opens and shuts at varying frequencies to bleed off enough pressure to hold a requested boost value.

If it goes bad it can leak pressure. If it isn't getting an electrical signal, or the logical information from the ECU is bad then the actual FBC may be good but the signal or wiring/continuity may be an issue. If you see around 10psi max this indicates the static boost pressure of the internal wastegate/actuator spring is probably controlling boost, and usually also means that your FBC is not working for some reason. Again this doesn't necessarily mean that the FBC is bad...its just not working correctly.

In addition your factory diverter valve, as well as any hose or gasket connection on the high pressure side of the turbo can be a boost leak culprit worth checking. Hopefully your dealership tech team actually troubleshoots the problem instead of just throwing on new parts in hopes of "fixing it".

Btw- The wastegate in our Evo's, is an integrated flap in the turbo housing which swings open to release pressure when a specific pressure threshold(controlled by the FBC) is reached.

The wastegate is opened by an actuator rod which is opened when a pre-set boost level is reached. The Wastegate itself is a simple device and they rarely "go bad' especially on new turbo's. The actuator canisters can go bad, but can be easily tested with proper pressure simulation tools.

If they are talking about replacing your wastegate, they will have to remove your turbo....or they may just be intechanging terms incorrectly and calling your FBC solenoid a wastegate as they muddle through trying to fix your car.

Keep us posted on what you find out!


N10S

 

Someone in these forums mentioned that we needed to upgrade to a stiffer wastegate spring if we decide to raise our boosts beyond stock, and they said HKS makes 'em. I wonder th Spring" has something to do with this....

STi

 

damn N10S, thanks for the info. i knew for the most part what a wastegate did but that was a good explanation. anyway like i said they ordered a new one so we will see if that helps. the thing not closing all the way and letting out pressure sure seems like it makes sense, the first thing i thought of when i had this problem was a loose IC hose which would also make sense, that wasnt it though. first night it stopped pulling at 5K and after that it boosted up, just not as heavy so loss of pressure in that turbo probably is it. ill keep you guys posted under this thread as to what the dealer says. hopefully the part will come in soon.

 

Mitsu has issued a tech talk article on replaceing the boost control/wastegate solenoid actuator

 

The same thing has happened to my car. All of the sudden one day it wasn't pulling like normal. It sucks. Sometimes feels weaker than others but that could just be the effect of barometric press, temps, etc. Either way, my RSX Type S pulled harder than my Evo does now.

 

Can you post the article?

 

I second that request !!

Btw-sorry for being too...well..."N10S" regarding my earlier feedback. Sometimes I just turn the wick up a little too far!
I read my own comments later and think "what a stupid @#$ing know-it-all " I can be.

Not my intent... just get carried away in the moment!

N10S

 

ill get it out asap

 

i have it in pdf format only, i could e-mail it if needed

 

pm me with an email address if u want the info. cant post, id lose my job