I have an 03 Evo and its been great until today. Few upgrades, was pushing 23psi without any issues, go in it today and maxes at 16psi. It feels like it hits a wall at that boost now. The gas is low on it, was on way into work when happened, wondering if that may be causing it. Not sure what to do. Checked over the car, nothing is loose or off anywhere. Spools great until hits 16psi and then feels like hits wall and wont build speed after that either. Has hardpiping kit, greddy catch can, HKS intake, greddy boost controller, greddy boost guage. Any troubleshooting tips would be great.

 

do a boost leak test.

 

Sounds like you are getting boost cut. Is your car tuned?

 

Is there a CEL?

 

I just took it out and pulled code P0234 which is an overboost condition. The car was tuned prior to me getting it. Has been fine for weeks until getting on the freeway today. Checked the boost controller its a manual greddy. Its plugged in and no boost leaks, all hoses are tight. It gets severe fuel cut at about 2500-4000rpms. Was spooling 23 psi, now starts to cut about 12-14 and feels like no real boost. Thinking the wastegate (stock) or BOV died.

 

You said like it hits a wall im leaning more towards a fuel cut issue due to the proof of that overboost code. I would still check for leaks though and have it tuned properly with the proper tools by a professional.

 

Ya not sure why would go out of tune out of nowhere like that. Same driving conditions everyday. Its getting sever fuel cut and states over boosting condition and know its from wastegate malfunction code. Not sure how to fix it. Ill dig more into it tomorrow when the motor is a little cooler from sitting overnight. Could be it a stuck wastegate or bad actuator? Car will keep driving but once hits psi it backfires, get off gas and hot it its ok until hits same boost levels

 

Do you have a wideband and boost guage. You should monitor that since you say it backfires. I remember when I had this problem with the other boosted car I had.

When you exceep the boost limit the computer will cut back and cut fuel to make sure you dont over-do it with the motor as a safety measure. I doubt if it was your fuelpump but lets not rule that out but it sounds more like fuel-cut to me from overboosting.

 

My gut says boost control or wastegate issue, but there are a lot of possibilities. If the BOV was bad, you'd certainly hear the other 10 or so psi escaping, even if it's not atmospheric vented (which it shouldn't be
Can you get freeze frame data from the over boost code?

 

How many times must it be said to do a boost leak test... visually looking at your piping does not execute a proper test, you must pressurize the system!

 

+1 boost leak test, tighten all your couplers for the hell of it, take of your wastegate and test, make sure your boost controller didnt come undone with the knob

 

I just took off the stock blow off valve and its wide open. Ran it last night and couldnt hear any leaks. Will be going down to tune shop tuesday to have it done right tho just as precaution but at this point looks like the BOV. Turbo is good though thankfully no shaft play and turns easily. Ill keep the updates coming in as I check it today

 

Also it wasnt backfiring, miss wrote that, it just hit fuel cut from it boosting so quickly and no way to pull rpms

 

Also it does have upgraded aluminum blow off valve, not the plastic one

 

I think the car may be in safe mode now so it doesnt overload it. Is there an easy way to reset it and clear the memory of the ecu of the code it through. Already cleared the code out