Mysterious Engine Trouble...knocking and power loss.

[Boostd4]

So just a little update...

Tried SiC's possible scenario and it still had the same result. Sounded pretty awesome with just a DP and TP though.

On to the next thing...any other ideas guys? Is it out of the realm of possibility that something is up with the ECU that can't be detected via logging or flash software?

[SiC]

Originally Posted by Boostd4

So just a little update...

Tried SiC's possible scenario and it still had the same result. Sounded pretty awesome with just a DP and TP though.

On to the next thing...any other ideas guys? Is it out of the realm of possibility that something is up with the ECU that can't be detected via logging or flash software?

Sorry to hear that, and sorry for the trouble of having to drop the exhaust to test it

[Hiboost]

See like you have checked over just about everything physically, is it possible something got messed up in your ECU with all the flashing? I'm assuming that the error checking it does at the end would make it fairly obvious that it didn't work right during a flash though.

Maybe another summary post listing all the things you tested would help rattle some ideas out again. Sorry to hear this is still plaguing you.

[spdracerut]

Are all the sensors working correctly? Is the coolant sensor reading okay? maybe it's stuck in warm-up mode? though... if the A/F is okay.... but, just an idea.

Oh, is there a way to log the actual position of the throttle plate? It may be that the throttle is not opening completely. Maybe part of the traction control? How's the tire wear? Maybe it's picking up too great of difference in wheel speed so it's kicking in some sort of traction control algorithm?

[Boostd4]

Originally Posted by SiC

Sorry to hear that, and sorry for the trouble of having to drop the exhaust to test it

Well, I'm willing to try everything at this point, thus I appreciate everyone's input .

Originally Posted by Hiboost

See like you have checked over just about everything physically, is it possible something got messed up in your ECU with all the flashing? I'm assuming that the error checking it does at the end would make it fairly obvious that it didn't work right during a flash though.

Maybe another summary post listing all the things you tested would help rattle some ideas out again. Sorry to hear this is still plaguing you.

We basically ran the gauntlet of normal physical tests: Leakdown/compression, boost leak, connections, etc.

While logging and on the dyno the AFR is solid at 10.7-10.9. The boost is solid as well (actually we can see that the car wants to go like a freght train as boost never tapers off).

No CELs and absolutely no indication of what could possibly be causing the power loss...and eventually the knock above 6K rpm.

Originally Posted by spdracerut

Are all the sensors working correctly? Is the coolant sensor reading okay? maybe it's stuck in warm-up mode? though... if the A/F is okay.... but, just an idea.

Oh, is there a way to log the actual position of the throttle plate? It may be that the throttle is not opening completely. Maybe part of the traction control? How's the tire wear? Maybe it's picking up too great of difference in wheel speed so it's kicking in some sort of traction control algorithm?

That's kinda along the lines of what I was thinking...maybe something in the ECU is putting a stop on the power party. Would a full ECU reset put the values of something like this back to normal...or is this something that is stored?

Tire wear is fine and when left in a "neutered" tune, the car runs just like a stock car...with $5000 worth of go fast parts on it .

As far as the throttle position goes, from what we can see it's acting as it should.

[Rguy]

Sounds like a bad MAF sensor. It's a common problem and im experiencing what you're seeing EXACTLY.

Replace it!

[Noize]

I hate you are still having these issues and am hoping for a swift resolution so the stress will end and you can once again enjoy your car!

[Boostd4]

Originally Posted by Rguy

Sounds like a bad MAF sensor. It's a common problem and im experiencing what you're seeing EXACTLY.

Replace it!

But were you throwing CELs? Mine "seems" fine as the AFRs aren't acting weird.

[Boostd4]

Originally Posted by Noize

I hate you are still having these issues and am hoping for a swift resolution so the stress will end and you can once again enjoy your car!

Me too brother...luckily I have an AWESOME shop (GST) and a great community to pull information from.

I'm just using the bike to supplement my speed fix for now lol.

[Hiboost]

When you say it starts losing power right at 6000, I noticed that the Cruise LTFT's switch over to another LTFT value that is usually leaner. Make sure you are logging the LTFT and try and tune so that they are as close to zero as possible. I've noticed my car (and many others) is "noisy" above 6000-6500 as well and there is always 1-2 knock counts in that region regardless of being run at 10.5 AFR or 11.5 AFR, 93 or 100 octane fuel, 23 or 26 psi, or 14* timing versus 17* timing. If it starts to go higher than the 1-2 counts then I actually worry about it. I think "Kooldino" is having the same issues as your car, unexplained knock levels out of the blue. The factory tune also drops 2 degrees of timing at 6000 so I'm thinking Mitsu knows there is some engine noise at that RPM.

Honestly 10.7-10.9 AFR is almost too conservative in my mind and it may be choking on fuel more than you think depending on what AFR meter you are using. Have you compared the onboard wideband to a dyno wideband so that you know they are close?

[DG Motors]

Originally Posted by hiboost

when you say it starts losing power right at 6000, i noticed that the cruise ltft's switch over to another ltft value that is usually leaner. Make sure you are logging the ltft and try and tune so that they are as close to zero as possible. I've noticed my car (and many others) is "noisy" above 6000-6500 as well and there is always 1-2 knock counts in that region regardless of being run at 10.5 afr or 11.5 afr, 93 or 100 octane fuel, 23 or 26 psi, or 14* timing versus 17* timing. If it starts to go higher than the 1-2 counts then i actually worry about it. I think "kooldino" is having the same issues as your car, unexplained knock levels out of the blue. The factory tune also drops 2 degrees of timing at 6000 so i'm thinking mitsu knows there is some engine noise at that rpm.

Honestly 10.7-10.9 afr is almost too conservative in my mind and it may be choking on fuel more than you think depending on what afr meter you are using. Have you compared the onboard wideband to a dyno wideband so that you know they are close?

+1...

[Boostd4]

Originally Posted by Hiboost

When you say it starts losing power right at 6000, I noticed that the Cruise LTFT's switch over to another LTFT value that is usually leaner. Make sure you are logging the LTFT and try and tune so that they are as close to zero as possible. I've noticed my car (and many others) is "noisy" above 6000-6500 as well and there is always 1-2 knock counts in that region regardless of being run at 10.5 AFR or 11.5 AFR, 93 or 100 octane fuel, 23 or 26 psi, or 14* timing versus 17* timing. If it starts to go higher than the 1-2 counts then I actually worry about it. I think "Kooldino" is having the same issues as your car, unexplained knock levels out of the blue. The factory tune also drops 2 degrees of timing at 6000 so I'm thinking Mitsu knows there is some engine noise at that RPM.

Honestly 10.7-10.9 AFR is almost too conservative in my mind and it may be choking on fuel more than you think depending on what AFR meter you are using. Have you compared the onboard wideband to a dyno wideband so that you know they are close?

Well, it has lost power basically everywhere, not just at 6K and above. I think my problem is the same as Dino's...just a little more prounounced since I have an aftermarket turbo in. It's almost as if the car is in a "safe" mode and power output is being policed by the ECU....or someone is joking around and stuck a tube sock in the intake manifold.

Bryan laid the original stock turbo tune over the Dom2 (and the Garrett tune) and the car is weaker everywhere after the turbo was installed. Bryan would be able to add color as to what values he's looking at on the logger. I think we kept the AFR very conservative since we were getting 10-12 knock counts above 6K.

[Noize]

Originally Posted by Hiboost

When you say it starts losing power right at 6000, I noticed that the Cruise LTFT's switch over to another LTFT value that is usually leaner. Make sure you are logging the LTFT and try and tune so that they are as close to zero as possible. I've noticed my car (and many others) is "noisy" above 6000-6500 as well and there is always 1-2 knock counts in that region regardless of being run at 10.5 AFR or 11.5 AFR, 93 or 100 octane fuel, 23 or 26 psi, or 14* timing versus 17* timing. If it starts to go higher than the 1-2 counts then I actually worry about it. I think "Kooldino" is having the same issues as your car, unexplained knock levels out of the blue. The factory tune also drops 2 degrees of timing at 6000 so I'm thinking Mitsu knows there is some engine noise at that RPM.

Honestly 10.7-10.9 AFR is almost too conservative in my mind and it may be choking on fuel more than you think depending on what AFR meter you are using. Have you compared the onboard wideband to a dyno wideband so that you know they are close?

Its probably fueled that way for a margin of safety against the unexplainable knock.

His tuner is Bryan at GST (formerly Razorlab), who is easily one of the best ECUflash tuners in the Evo community. He knows exactly what he's doing, there is not an issue with the shop's equipment either, I'm sure of it.

It is simply an issue with this specific car that needs to be discovered and sorted out.

[Boostd4]

So I've gotten a few PMs and have been a part of a thread on another forum about this issue...it appears that I'm not the only one. I'm beginning to think that this may be affecting others...but they just don't know it yet.

Have any tuners run into this issue? And if so...would you be willing to share your fixes?

[blk-majik]

Did you try replacing the MAF yet? You said you found another local X who would let you borrow some parts to test... seems worth the hassle if you didn't try it yet. How is your EGT reading (err...nvm unless you installed an EGT sensor)? I was thinking LTFTs as well... might be worth double checking, especially if its outside +- 5%