1.4t 5500rpm issue

Hey dudes. Working on my Soinc tune right now and I cannot for the life of me figure out this issue. Ive ran into it a couple times now. The car is pulling pretty good, making some steam, and then right around 5500rpm it falls on its face and sounds like Im smacking the shit out of a rev limiter, just really fast. Logs show the TPS goes down to around 50%, but I dont see anything else. No significant amount of KR or anything. Sometimes it powers through it, but doesnt pull as good after that till redline, and sometimes it does this. Here's the tune and log file. Its towards the end of the log. And yes before you say anything my LTFT and shit are way fucked up, I know. I havent been able to tune my MAF yet because my wideband isnt wired into HPT. But I keep an eye on the wideband as I drive and the AFRs are perfectly fine, even at WOT. Thank you for your help.

Look at ECM 12067, you're probably making enough additional power that the ECM is starting to pull power at 5500 even though the limiter is set to 6500. The ECM will start to limit acceleration at 5120 by 1000 RPMs, so near the 5500 'wall' you're running into.

sometimes users say that the knock airmass table gets in the way too. if you didnt change those try increasing the values in the zone you have issues.

Scarab, I saw that before and wondered if it would ever be a problem, but didnt really understand it. Can I just zero the table out so it cant limit based on acceleration at all?

Cobalt, I have messed with that table before a little. If the accel thing doesnt pan out I will check into that again.

Unfortunately guys it was neither of those things. No change at all

I shouldve mentioned this in the OP, but the issue isnt at all times. I can free rev all the way to the 6500 limiter with zero issues. Also, if the wheels are slipping pretty aggressively, itll go right to 6500 too. So its only when the car is under high load. Makes me think it is some kind of torque or load limiting parameter.

Just a quick glimpse at your tune, and I think you might have overshot the Driver Demand MAP.

The DD Areas you changed, your demanding 250% more power than stock. That's not gonna work every time, thus makes the ecm freak out.

Scale it back closer to a more realistic number.

Try scaling those areas to 1.5x over stock and see what happens.

I will give it a shot. But Im gonna go ahead and mention that its never been a problem before. It only started happening when I brought the boost up over 20psi. I ran around with the boost test set to 20psi for over 6 months. And the past six months I had boost test disabled and the driver demand map looked just like that. Now I raised it to 23psi. So if Im not mistaken that means the driver demand map is irrelevant right? It just goes off the boost?

Okay scratch all that. I just tried it and it seems to have helped for sure. I thought that boost test made the driver demand map irrelevant, but apparently not. I disabled the boost test and lowered the torque numbers to much closer than I am actually making. However, it seems like I am making a little less boost so maybe that was the fix. But now I am still having the problem I always had and gave up on fixing out of frustration. As the RPMs climb past 4500 and on, the desired boost drops so my actual boost drops. I could never figure out why this is happening. I want to get a tune stable at 22-24psi all the way through before I put my big turbo on. Heres the tune and log. The pull is near the end, sorry. Kept getting stuck behind slow ass people.

This is probably nothing but I would change this one little thing...

Torque Management \ TC/SC boost control \ Boost Limits... Boost MAX limit,.. Under the 140 f headder you have it set to 200 kpa and I would change it to 270 like the others before it.

I went ahead and changed that one. If it made a difference I cant tell. The desired boost is dropping all the way to 15psi from 23-24. No significant knock or anything. If you look at my timing tables, I have this thing running pretty retarded up top under high boost.

Even so, for that few seconds where it is pushing 24psi, its making some power for sure. Roads are wet right now and it was trying to spin 4th gear which was never even remotely happening at 20psi. Anybody that knows these cars knows thats pretty impressive. These things dont spin much. Super shot gears, good sized tired and all the weight on the nose equates to impressive staight line traction for a FWD. The N/A lancer I had with barely half this power spun much worse.

I'm thinking you should try lowering the driver demand a little more in the 90% & 100 % TPS areas so none of the boxes are more than 80 above factory.

Then copy DD MAP A to DD map C. just to make sure they're not at odds. I even copy map A to map B as well as the map C just to rule out any ecm calculation errors.

Do you know how to use the "Compare" feature in HPT editor ??? It's the easiest and quickest way to compare from stock and make changes.
Here is a link to a tube video on how to use the feature. This way you can add 80 over the factory DD numbers in an instant.

https://www.youtube.com/watch?v=9YCWc9D9jiI&t=138s

As I thought, it didnt work. Honestly I think the torqe demand being higher than delivered isnt really an issue especially when its within 20-30 of what the car is actually making. I agree that the way I had it originally where it was over 100lb ft higher than delivered was probably not ideal. But I would think that if that was an issue, it wouldve tripped some sort of CEL for low performance or something, but it never did. Regardless, I lowered it even more and it still didnt fix it. However, the 5500rpm thing did come back for a second, and then didnt happen again. Mid way through the log is when that happened.

Try maxing out the Overboost Limit table to 6042, I found that to limit my desired boost, Here is my tune for reference from my 2014 cruze 1.4t. It holds 23 psi all the way to 6000+

My cobalt did the same thing and it turned out to be bad injectors. The were good until about 4500 on mine then did the same thing. Mine didn't throw any lean codes or anything so maybe it worth looking into.

Hey guys. Forgot about this post there for a bit. Im glad to say I fixed the issue. I finally got around to wiring my wideband into a serial port so I could datalog it and therefore tune my VVE and MAF. Once I did that, the 5500rpm thing fixed itself, so it must have been related. Now Im trying to figure out why its commanding a richer ratio than my PE table. Probably a temp thing somewhere, Ill figure it out.

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Originally Posted by Derpy Dylan

Hey guys. Forgot about this post there for a bit. Im glad to say I fixed the issue. I finally got around to wiring my wideband into a serial port so I could datalog it and therefore tune my VVE and MAF. Once I did that, the 5500rpm thing fixed itself, so it must have been related. Now Im trying to figure out why its commanding a richer ratio than my PE table. Probably a temp thing somewhere, Ill figure it out.

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Mine was doing the same. Go to fuel-temp control and turn down turbo protection max enrich and cat protection max enrich. They are set at 1.42 and 1.37 from factory,respectively.

sub'd for when this issues comes back