i was working on a friends evo9 tonight and its got a unique problem that i've never seen before. Figure i'd pick some brains on EvoM if anyone has a better idea of what might be going on... anyways it drives fine and feels great during spool but it stops at 12psi (wastegate) no matter what and THEN creeps to about 15-17psi when you hit 6000rpm or so. Really weird. This happens whether or not you have the MBC open or closed all the way. So i've ruled out the MBC. Plus another MBC was tried earlier. It also passed a boost leak test. Everyone was pointing blame to the stock wastegate actuator... so i replaced it tonight. Nothing... same problem. One last option would be a faulty BOV, but the factory one is being used and i cant see how that could have failed. Other wise the datalogs look fine except for the strange boost curve. No knock at all and no jumpy airflow readings. I checked the ROM and it looks like a fine tune. Typical off the shelf tune from a well known and good vendor. (i recognize the base tune). Timing is conservative fuel looks right for a stock evo9 w/ just intake/exhaust. Again... weird... it hits 12psi right away... and stays stuck until 6krpm then it slowly creeps to 15-17psi. The only time i've seen a similar problem was when someone was running a stock solenoid and didnt have the proper pills. but in this case its bypassed w/ a hallman mbc.. any ideas people??

 

The BOV was swapped out for an HKS at one point, then swapped back to stock. I'd check to make sure it was installed properly, and wasn't damaged while it was out.

Also I recommend putting it back to ECU controlled boost on the stock solenoid, just to see what it does. It was making 15psi on the other WGA, so if it's only making 12psi on the other WGA then it's just that the WGA are adjusted differently.

I drove her car before it had any of the bolt-ons installed, right after driving my own RS out to Houston, and it seemed to pull a lot harder than my RS, so I think it was making more than 15psi before all the bolt-ons. I don't know for sure, but I know it hit harder and seemed to pull harder than mine, which has just the base stock tune and zero mods. But putting it back to ECU controlled boost would at least give you a safer boost level, yet still try to generate more than 15-17psi. Opening the MBC all the way is just plain dangerous....

 

Mike, when you drove it, it already had the tune from the previous owner though, didn't it?

THIS SUCKS!!!!!! UGHHHHHHH

Carl is going to check it out in about an hour, so I'll see what he has to say

 

Yah it had the tune, but I don't think it would have pulled harder than my RS even with a tune if it was only making 15psi. I didn't look at the stock boost gauge when I drove it though, but 21psi untuned vs. 15psi tuned my car should have felt faster.

It could be the stock BOV, who reinstalled it for you? Do you notice if the car feels any slower than before you put the parts on?

 

Thx for the history on the car. Its definately not the wastegate, so at least we ruled that one out. I put my IX stock wastegate on their and it was functioning perfectly fine on my car. In fact her's had no pre-load and was loose, but thats besides the point. We could try ECU controlled boost, but there is an issue. Michelle doesn't have the stock boost pills for the lines. You HAVE to have them in the lines in order for the stock BCS to work properly. Otherwise you'll have unstable boost. Either too low or uncontrolled spikes. Trust me on this one. A MBC is a simple bleeder device. If anything its making the trouble shooting easier by ruling out the boost control as a culprit. W/ it shut it should ONLY see wastegate pressure. W/ it open it should raise boost. What its doing is seeing 12psi for the majority of the pull and then creeping to 15psi or so near redline. I was guessing that perhaps the BOV was leaking or not installed in the right way (backwards perhaps?) we need to double check that again. I did notice earlier that whoever installed it did a pretty sloppy job and it had a visible leak where the clamps werent even on. That is fixed... but i didnt bother to check if it was facing the right way, lol. Either way... i highly doubt that is the culprit either... but worth checking to cross it off the list. I downloaded the ROM. This car has been tuned. The fuel and ignition is conservative but definately better than a stock ROM. I've seen base maps like this make good power on a stockish IX. In fact its similar VERY to my first flash on just intake/exhaust that i made 340whp on. Probably why her car feels pretty strong even at just 15psi. Pulls very smooth. So just need to figure out this odd boost limiting problem and im sure at 22-24psi it will be a strong Evo9.

 

btw... if you RS is stock w/ no tune... then you are also just holding about 16psi to redline. The 20psi spike you may get around 3000-3500rpm is brief and it will shoot to 16psi immediately... so its very possible that her tuned 15-17psi near redline feels faster. but her initial hit of 12psi is weird. Hopefully we'll solve this mystery soon!! dyno day is saturday! Lol....
what do you think about this... I suspect those rubber lines from the wastegate to the hallman MBC. If there was a slight tear or hole in it (that we all missed) it would bleed air and cause it to probably act this way regardless of how the MBC was set... Someone should double check these lines or simply REPLACE them w/ new ones just in case. its a cheap fix. I've had a few rubber lines come new w/ tears and holes so its not too far fetched... at least rule that one out too...

 

Hmm, that's strange that the pills are not in her boost lines. She had it with all stock parts on it when she got it, so either it was driving around on ECU controlled boost without the boost pill for a while, or the lines got swapped out when she had the MBC installed.

Are all the vac lines in good condition? No leaks in the lines?

 

Yeah mine spikes 1.5bar and holds around 1 bar at redline, but it was the initial spool of her car that impressed me before. When I drove it about 3 months ago, the initial spool seemed more aggressive than mine, so if it's only getting 12psi now I think something must have changed. I know she had all those bolt-ons done after I drove it and I haven't driven it since, maybe something wasn't installed properly.

And yep that was my next thought that I posted as you were posting this reply, heh, vaccuum lines. Even a pinprick in the lines will do it.

I need to steal a copy of her ROM for my RS, haha.

 

Hallelujah!! its been fixed... Lol... a local Houston tuner Hellcat (Carl) was troubleshooting the car and it seems it was a combination of a failing wastegate and the Hallman MBC missing an internal ball?! Well, thankfully the wastegate i replaced wasnt in vain... and Carl had replaced the MBC w/ his own... and now i hear its boosting 22psi happily! We have a happy owner again... w/out the cursing, lol...

 

Lol I wasn't cursing! Well I don't remember cussing in front of you.. but I know for sure I was cussing when I was by myself Thank you Tom, Mike, Carl and all who helped!

 

Now that you've got all the boost you've been missing, save up for a good set of tires so you can keep that beast on the road =]!