I noticed the other day on the highway when I floored it in 4th that my mitsu gauge showed a spike past 1.5 to around 1.8-2.0 bar before leveling off between 1-1.5 bar. I did the psi conversion and 1.5 = 21.7 PSI and 1.8 = almost 27 psi. I would imagine that 27 psi on 91 oct untuned is a problem.

Anyways I did some more testing last night and in 1st and 2nd gear I spike to 20psi and then level out at 17-18 psi, but in 3rd and 4th I spike to 26-28psi and level out on 17-18psi.

I bought the car last week and it is a stock IX MR. I checked but did not see any kind of boost controller so I believe it to be stock. I plan on doing some more checking this weekend but wanted some direction.

Any help or thoughts would be appreciated.

Thank you

 

Higher gears=More load
More load=More boost

Check for a boost controller and turn it down. That is WAY too high.

 

Thank you, I will stay out of boost until I sort this out.

 

What you are experiencing are boost spikes, not creeps. Boost creep is when your boost continues to rise towards redline, meaning your wastegate cannot bypass the amount of exhaust it is suppose to.

Someone please correct me if I'm wrong.

 

ok you are right I google it and found this on dsm tuners.

http://www.dsmtuners.com/forums/arti...ost-creep.html

So I may either have an mbc which is set to high or a faulty stock boost controller?

 

Correct. If you don't have an MBC, its possible that someone removed the restrictor pill in your boost lines. I'm not too sure exactly on how that works, but I heard removing it can raise your boost to 25 PSI.

 

ok I will search for info on this and take off the stock airbox to get a better look at the situation, thanks for the help.

 

ok I checked and no MBC installed, the stock lines seem to beem connected correctly. Any chance that there is a tune on my ecu?

I am wondering if I should just take it to Mitsu and see what they say.

 

If you go to the parts counter at the dealership and get a new vacuum/boost hose assembly, and remove what you have and install the new factory one then let us know if it still spikes. Probably the previous owner either removed the restrictor pills in the factory hoses and/or was running a boost controller and reinstalled other non factory hoses before he sold you the car.