David Buschur

iTrader: (53)

No this topic is not about someone's *****

Seriously. The EVO X has a problem that I think Mitsubishi screwed up on. The car will go into a limp mode. I've had it happen to me twice now and know other shops have had the same thing happen.

Last week I was coming home from work. I went to about 50% throttle in 4th gear, which would produce peak boost with our manual controller and the car "backfired" it felt like typical fuel cut. Problem was after this happened the car had very little power. I drove the few miles that were left to my house, pulled the code and reset it with the scanner. All was good. The code was for the TPS. This made no sense. I have not touched the throttle body or any other wiring on the car.

Last week Robert and I were driving the car, again back to my house. I left town rolled into the throttle in 5th gear, again maybe 60% throttle and the car did the same "backfire". It actually felt like the i/c pipe blew off. This time was horrible, had I been in heavy traffic we'd have been killed. I could barely get the car off the road as the top speed as 20 mph. Nothing over a few percent of throttle opening would make the car move. I pulled the code on the side of the road, again a TPS code. It would not re-set. I cussed the car, cussed Mitsubishi and wished for the 4G63 and old stuff to come back! haha Then finally the code re-set. All was good again.

So, this is all I can figure and I am basing it on tuning the drive by wire ECU's in the Subaru's. My guess is because of the manual boost controller and no engine management on the car the car is seeing too much load for a given throttle percentage, when it sees this it is shutting the car down and limiting the throttle opening.

For those of you that are putting a manual boost controller on your car I just want to make you aware of this situation as it is a huge safety issue. It has only happened at part throttle, "high" boost situations. If I run the car directly to WOT it will NOT happen, ever. I have tried to force it into that situation and it won't happen.

We need some freaking tuning software!! I know it's coming, I can't wait.

Please be careful in the meantime.

Have a great day and enjoy your cars.

Ultimate CC

iTrader: (122)

that would drive me nuts but I doubt it will be much longer before the software is available...

mrboostt05

great info nice to know wondering y you get tps code i cant understand that one i just got back from west chester pa and test drove one today and no problems outta that one stock tho +1 for the info is there anybody specfic thats working on software now ?

quickgti18t

welcome to DBW, I deal with this crap all the time... It usally happens with MBC controllers. Our limp mode is different it limits the boost to 5psi and is slow as ****... Faster spooling turbos seems to have these problems more then the larger ones.

STi2EvoX

Well, I see this as the ecu being "too smart" and making the car react in a paranoid manner when there is increased boost without a tune. All the breathable bolt ons seem to react quite well, though. Once tuning software is out, it'll be all good. Al, does your X have this notchy, crunchy shifting issue in the first 3 gears like so many of ours do? Mine seems to almost be getting worse in that it's doing it on downshifts now, when it only used to do it on upshifts. Speedshifting is smooth, but normal paced shifting feels awful. I am getting more and more frustrated by this everyday. Any info would be appreciated, thanks.

mksevo

what Boost level , maybe you can turn down the peak boost based on that 4th gear 50% run.

DynoFlash

iTrader: (91)

I worked on a MAzada Speed 6 with a similar problem - if the desired TQ is higher than what the ecu has been mapped for the car will enter limp mode.

When we get the Ecutek this problem will be easy to correct.

Al

Ivan@AMS

We have been tuning with the piggyback system for several days now. For those that are concerned, we were able to eliminate boost cut and get our A/F ratios sorted out.

350 whp on 93 octane so far now that we have control over fuel, timing and boost cut.

Ivan@AMS

Quite possibly backfiring though the intake causing the TB to change position and be outside of commanded range. I would suspect that Mitsu would be quite aggressive with getting the car stopped if the DBW throttle seemed not to be responding to the commands it was getting.

Jameson_IXMR

iTrader: (5)

I would completely agree with mitsubishi's decision on shutdown if the TPS is not responding well. I would imagine it uses a 360 degree potentiometer rather than a sweeping type. This would allow re-calibration of the tb on conditions like the above mentioned. What would be causing such a serious backfiring through the intake would be my question? In any case, I would assume that the tb goes through a little cal test either on startup when the ecu syncs to the engine or at variable conditions such as when the code is reset and the engine is cranked after. It concerns me that they would make such a large effort to protect the engine, at the price of sacraficing safety. In N/E to Central FL, if you slow to a 20 in afternoon to 8pm traffic, your getting hit, no doubts about it. Glad you escaped the situation unscathed Dave.

bchappy

this seems to be the same problem that SRT guys have been dealing with.
Its a bad case of PTOB(part throttle over boost) light throttle load and a **** load of boost makes the computer go crazy.
Do you really want 19psi at 60% throttle? Your not receiving enough fuel and bang you get your fuel cut.
Is the boost pretty eradic at part throttle situations?

Jameson_IXMR

iTrader: (5)

^That is a really good explanation.

I wonder how tunable the stock boost control system will be? How the maps stack up in the ecu. Looking at the system I feel the car might be one of the few that can benefit from tuning the stock boost control system.

bchappy

yes its all tunable but you would like a linear boost responce.
Dont hate me for saying this but as much as I have read on the new evo X alot of the little tuning gremlins and power characteristics remind me of the nSRT4 platform.
I am willing to bet that is whats going on... and if thats the case than you can obviously see the negatives of severe PTOB situations.

David Buschur

iTrader: (53)

Yes, I do want 19 psi at 60% throttle, you don't?

The problem is simply a software problem, when the correct tuning software become available it will all be sorted out.

I have no desire to hack into the factory wiring with any type of piggy back controller and that's why we haven't done it already. We went down that road with AFC's and such on the EVO8-9's. It just makes for a mess later when customers come in with poor wiring that has to be sorted out. I'll be patient and wait for Ecutek, Cobb or something else.

We are up over 100 whp at redline already and are shipping parts. It's all good.
We will wait to do it the RIGHT way so it can be done once.

Noize

iTrader: (24)

IMO, the solution is to run the MBC at no higher than stock boost levels until EcuTeK or something else comes out. My car has not done this, but it runs 22psi peak. At partial throttle, it hits about 17psi. Even though its nearly the same peak boost level as stock, it tapers substantially slower.

Thanks for the heads up.