- Three days ago I had 23psi of boost
- Two days ago I had 15-18psi in the morning, 10psi in the afternoon
- Yesterday I had 5psi
- Today I have 0.

When trying to spool it makes a "popping" sound like small fuel cuts, and this also happens in a vacuum. I've checked all the IC piping and couplers (no tears/clamped down tight) and the majority of visible and reachable vacuum lines. I switched to the stock boost controller, and that didn't solve the issue. I also checked the turbo for play and there is basically none. My next task when the evo cools down more is to check the wastegate (not sure what to look for).

What is going on right now evo community???

 

Check your plugs....I had a similar thing and I replaced the plugs and good as new

 

Spark plugs?

Or Super Nintendo plug?(<---- jk on that )

 

Replaced all the plugs, and found that the cylinder-3 plug wire is compromised; the little metal rod won't stay inside. Just ordered a new one and hope that is the issue. Otherwise I did reach 10psi a little bit ago.

 

Update: Changing the spark plugs and the one bad plug wire did fix my running rich/misfire issue, however the boost issue still continues.

If I gradually build boost I can hit 20+/- psi, but if I go full throttle I'll hit anywhere between 5psi and 20. I checked the BOV and the spring seems strong..

 

Due a boost leak test might have a cracked hose somewhere in a place you couldn't get to. Check hose going to wastegate. Sounds like the WG is not staying closed due to not enough vacuum to keep it closed, Which is why you can build boost when you slowly press the gas as opposed to when you go WOT.

 

Please give detail on your boost control method.
-ECU/Stock solenoid
-MBC

etc

 

I have a Hallman boost controller; switched over to the stock solenoid during troubleshooting and it made no difference. I did notice and learned the hard way that the vacuum line leading to the wastegate is fairly brittle as I tore it a few times hooking it back up to the MBC.

I have been trying to get my buddy to do a boost leak test but we've both been pretty busy. Gonna check the vacuum lines around the wastegate for any cracks tomorrow. First day off in a week