supak111

Hey guys my Evo felt kinda of low on power after 5k RPM so I got a boost gauge and just as I tough it wasn't boosting fully. Its only boosting about 11-12psi.

TESTED:
I've tested the piping up to 25 psi and and even though I do have a bit of a leak on the TB seals its not really bad so the piping is OK.

Tested the boost solenoid thats right under the intake pipe and it works as it should. 12v turns it ON and it lets air out as it should.

All I can think is maybe boost solenoid isn't getting power from the ECU, not sure if anyone has ever seen that happen but I will have to check. I'm guessing the ECU controls the boost solenoid depending on what the MAP sensor is reading. If my MAP sensor wasn't working right wouldn't I have some check engine codes? I only get a O2 sensor code once in a great while but I just though my O2 sponsor is on its way out.

Does anyone have any idea what could be my issue?

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LetsGetThisDone

iTrader: (1)

I'm pretty sure 12v should close it, and prevent air from going to the wastegate actuator.

egis

Can you try to to bypass solenoid and run on wg spring pressure? You should get more then 12 psi.

stefenboy

iTrader: (1)

What was done to the car before this happened?

kaj

iTrader: (60)

what IS base psi on the OEM WGA? just curious. bump for reading.

supak111

I've tired it without the solenoid, just one line going from boost to wastegate and it seems to still get same 11-12psi. Car is stock, I just purchased. I just bought TB seals, I'm gonna have them replaced and see if that helps. Because when I was doing the boost leak test leak on TB wasn't too bad but who knows if its bad when you hold the TB at full throttle and full boost while driving.

12volt opens the solenoid for sure because I bench tested it. Here is how my boost solenoid diagram set up looks like, maybe someone connected it all wrong perhaps?

PS from what I've read people say boost on wastegate alone without solenoid should be 11-13psi.


Evo 8 boost solenoid diagram, correct or wrong?

kaj

iTrader: (60)

Did your replace the vacuum lines? Sounds like the boost "pill" is missing?.

supak111

I didn't know Evos use pills in the turbo lines. After a quick search they sure do. I will check tomorrow.

Its very possible that the guy before me had a boost controller that he took out before he sold the Evo.

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kaj

iTrader: (60)

most likely, yes. you remove the pill when using any type of boost control. it would be a plastic piece in one of the lines. kinda looks like a check valve, if i remember right. i have mine in the garage and can take a pic tomorrow, if you want.

Sheasta

iTrader: (7)

11-12 psi is stock waste gate pressure so your boost solenoid isn't working. Just buy a boost controller.

supak111

I just checked and the "PILL" is definitely missing in my stock boost solenoid lines. I will get a manual boost controller or buy the stock lines, they are only like $25.

Will report back if the problem continues.

kaj

iTrader: (60)

I'm 99.9% sure that's your problem. A MBC is an easy fix unless you plan to stay stock, no tune, etc.

supak111

Yea the car is 100% stock, doesn't even have an exhaust so I might as well keep it that way.

I make a stupid mistake a little bit ago. When I was removing the intake to get to the lines I broke the vac/boost line nipple of my BOV now I either have to get a replacement or I might try epoxying the thing back on.

kaj

iTrader: (60)

Ah. Plastic OEM one? If it's in your budget, pick up a used IX DV. all metal.

Whistlin.evo

Hey man I'm having the same issue as you, did you end up finding what was wrong with it? I can't figure it out.