Last night while driving home from work my evo started to feel sluggish. It won't build boost at its normal rpm's. If I'm lucky i'll get maybe 1 psi in 1st and 2nd gear. I've checked intercooler clamps and they seem fine. Vacuum lines appear ok as well.what could it be?

03 evo with 83k miles. Stock motor. Pt61 turbo. 3 inch exhaust. Walbro 255. Twin disk clutch. Stock ecu with safc.
Car was set for 23 psi and before this started happening I was only hitting 15 due to the wastegate being stuck open. Note the wastegate is still stuck open.

Thanks

 

Fix the wastegate first. If the wastegate is stuck open the turbo is going to struggle.

 

Im going to try that tonight. When it first got stuck it was still boosting normally just woldnt hit 23 pounds.

 

Impossible a WG doest work that way.

A WG makes you build boost and then when you get to the amount of boost you want, bleeds off exhaust pressure to maintain and not exceed that boost level.

If it is stuck open then it will take forever to build boost and possibly not hit full boost, like youre describing now. It could not have been stuck open and allowed you to build boost (spool) the same as when it is closed. Physics just won't allow it. LOL


Sounds like you had/have another another problem too.


Other options are that your WG is fine and you have a boost leak that's just gotten progressivly worse....I'd start there.

 

Get a boostleak tester and attach it to the turbo get t-bolt clamps for all the stock clamps replace the stock clamps with t-bolt clamps. You should hear a hissing noise if there is a leak when you when you hook up the boostleak tester to a compressor. Watch the psi guage go up on the car make sure the car is off when your boostleak testing it. If you have any leaks they should expose themselves by then with enough pressure.

I think 20 psi should expose it or 15 at the least. If you dont hear any hissing noises or wind blowing where you hear the hissing noise from you should be good. Try to also spray soapy water that way you can see where the leak is coming from. The wastegate should not be a problem. If its calibrated correctly it should not be a problem. Also make sure you ziptie all your vacuum lines and I mean all of them.

 

Thanks I'll try the test. Also all clamps are t bolted and vac lines are clamped or zip tied.

Also the car runs fine under just vacuum if that helps.

 

They are probably loose then or perhaps a coupler you may have may actually have a slight leak or in my last situation I had with my srt was with the intercooler had a small tiny pin-hole leak. The boostleak test reveals alot.

 

Did the leak in your srt make it extremely difficult to build boost since it was so small?