I am having an issue with my evo. Current mods are RnR 3" turbo back, buschur intercooler with intake upper pipe, intake and a MBC. Everything was going perfect for the first few days. Then one day I was driving and the engine cut out on me. got a cel that was P0234 meaning overboost error. I had boost set at 19psi to redline. I set it back to 16psi and reset my ecu. Still same problem. I cannot let the turbo spool anywhere above 9psi without the ignition being pulled completely, and cannot build rpm's.

I have checked all connections, no leaks or anything. Took out MBC and put stock boost controller back on. Still same problem. I have reset the ecu about 50 times. This is driving me insane!!!

 

hrmm sounds like Fuel Cut.... does it only happen with WOT?

 

It only happens when I let the turbo spool over 9psi. Under wot or not.

 

odd, it sound like what happens to me when i hit fuel cut, but i've only had it happen at WOT, but it feel like a Jolt when it does it, and i've even done it three times in a row, (which freaked me out) and it kicked on the CEL, but i just cleared it knowing what was happening. I've only trimmed off 1 LB of boost, since it began to get cold, and it seems to have helped alot, i've only hit the cut 1 time, since then, where is at 21.5/22 i was hitting it frequently.

I'd take it in....because that sounds like another problem...

 

I don't have the manuals in front of me right now, but I'd look to see where the ECU is getting it's boost data from. If the ECU is getting it's reading from a different part of the intake system than your boost guage, I would try to get a reading at the ECUs sensor point.

If both points are showing comparable boost, the sensor is probably bad. If the ECU sensor really is seeing an overboost, you will need to trouble shoot your intake side to see why your boost guage, ECUs boost sensor and MBC are not all seeing basically the same PSI.

 

It could be a computer problem...I had that happen once with no modes...the CEL came on when I reved up just a bit while climbing a hill in 1st...(I was going super slow)...turned out to be a computer error...I took it to the dealership the next day and they said it was a computer problem and they could not recreate the errors it was giving....

 

Phatcat, put your stock filter back on and reset your ecu and see it that helps. Your MAF sensor might be damaged, I could be wrong but I had issues like yours in my Supra twin turbo. Had to replace the sensor, it cost me a fortune. I will look at my OBDII scanner manual when I get home and figure out your CEL code.

 

DynoFlash would solve the "fuel cut" problem...

 

jimmy, p0234 is an overboost condition. in order to trigger an overboost, the manifold pressure has to detect 30psi. god i hope you werent running 30psi.....

 

If your MAF isn't plugged in you will hit boost cut at 10~ psi.

 

Is your MBC plumbed correctly?

 

Check out my post.. But I did NOT get a CEL... https://www.evolutionm.net/forums/sh...threadid=48706

 

If the stock fuel cut is their to protect the engine from damage and the Dynoflash raises the fuel cut threshold wouldn't your engine be more prone to damage?

 

bump

 

I have no idea ...I'm not the world most mechanically inclined person, Someone else would be better suited to answer this question