So the other day I did a boost leak test because evo could not boost pass 10psi. Turns out that I had a major boost leak in the TB so I replaced the TB shaft seals with the ones I ordered from MachV. Everything was installed back on correctly. Did boost leak test again, no more leaks. Took evo out for a test run. Stepped on gas, takes forever for car to build up boost and speed. When engine is at 4000 rpm, boost gauge shows vacuum of 10. At 5500 rpm I start seeing a little boost, I max out at about 17-18 psi when I hit redline. It's really annoying especially when you come to a full stop at stop lights. Car picks up speed slower then a Kia. Am I still having a boost leak somewhere? Any help would be great! 2003 evo 8, car has aem intake, hks bov, autometer boost gauge (bought car with mods on).

 

did your evo ever boost more than 10psi? what are you using to control boost? are you 100% sure you reasembled the tb back together correctly?

 

When I first bought the car, it boosted normally and ran normally. Yes, I did boost pass 10 psi once I replaced TB shaft seals. As far as installing the TB correctly I'm positive it was installed correctly. when you start up the car, it idles normal, right under 1000 rpm. I'm thinking about taking it to the shop. what do you guys think? car just does not move until about 4000 rpm. One last thing I forgot to mention is that car did the same thing before TB seals were replaced but worse because of boost leak.

 

anyone??

 

Honestly it sounds like you have your wastegate stuck in the open position.

That or you have crushed your intake pipe into a pancake but i was thinking thats too obvious, good luck btw.

 

Do a boost leak test. Also, replace the HKS BOV with a factory, metal, diverter valve. How are you controlling boost? Give us the brand name of the boost controller that´s on your car. Describe the vacuum hose routing from boost controller to wasegate actuator, and from boost reference source to boost controller. Also, you might want to check how easily the threaded actuator rod slides on and off the flapper valve pivot arm on the turbo.

 

I've done a boost leak test. No leaks. Evo does not have a aftermarket boost controller, all stock. If it is a wastegate problem, would it be an easy fix. Kinda new to turbo systems and don't know much about wastegate or how to check if it's bad or not. I'm trying to learn so could someone explain how it all works or show me where to find the info.

 

If you bought the car used, then all bets are off until you replace your car's existing vacuum/boost lines with a set of factory boost lines. It is available as a complete assembly from the parts department at your nearest Mitsu dealership. It includes a couple of strategically installed restrictor orifices which are crucial to the proper functioning of the stock boost control system.

Then I'd say get a stock Mitsubishi IX diverter valve to replace your HKS BOV. Once you do both of these things then you will have a solid base reference point. The previous owner of your car may have not returned the car back to stock boost configuration.

 

damn sounds like your ***ked, but ey like the rest says check your vacuum lines. Oh and when you installed your TB your line that goes to it did you installed that correctly/?

 

Knew the guy that had the evo before I bought it...I'm the second owner...all vacuum lines and boost config are stock and was never modified in any way....as far as the bov, I'm not venting to atmosphere...spoke with a buddy of mine and he thinks that clutch might be going out....

 

Just make sure that wastegate control arm is still connected to the wastegate flap on the turbo, if it fell off its easy enough to put back on. Also as another note there should be a fair amount of tension before you can move the flapper if not it could just be adjusted very very loose.

Adjust the wastegate by turning the arm to tighten.

 

If it was the clutch slipping it'd be revving freely as if you were at idle revving the car and then once the clutch grabbed it would go. Idk what the hell is going on. Id take it to a shop.

 

Could it be a boost solenoid problem?

 

Could be, but since the boost solenoid is controlled by the ECU (I believe please correct me if im wrong) than it should since something isnt right and throw a code.

 

I can't say that would be the problem.

he should at least be hitting waste gate pressure with the pill thats around 12-14psi but he doesn't hit even that until extreme revs. This still screams his waste gate is stuck open or the arm has become detached from the flapper.