Tuners Rejoice! Free Tuning For M4.4!

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34 minutes ago, gdog said:

Had mine disabled for years now.  I think it's too sensitive TBH.  When I first started M4.4 DIY tuning, had same experience as on your GLT; random phantom misfire codes.  Finally just disabled it and haven't looked back.  But if you do start experiencing real misfires, then you can turn it back on; hopefully will help locate which cyl is misfiring.

BTW is the GLT an auto or manual trans?  Wonder if that's common.


Yeah, I've seen the disable, just wasn't sure if it was a good idea or not to shut it off. The car never had any issues such as this until we did the COP and fiddled with the VVT. Not sure if there is a correlation or not. We ran the car on the original M4.4 DIY set-up with a dist for like 2 years with maybe 1 misfire code the entire time. Now we get ALL of them, without any of the expected signs.

This car has fought the COP conversion much more than my T5 did. I think the misfire detection is still enabled on my car as well.

The GLT is an auto. My T5 is a manual.

I should have time to grab a datalog tomorrow evening after work. Maybe that might point towards an actual issue/cause. 
I'm probably going to pick up a smoke test set-up this weekend, and MAYBE I can uncover some hidden vacuum leak, but I'm not holding out for one.

Thanks for the input.

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OK, got a datalog this evening.


The yellow is the "FC12" monitor, or the one Aaron set up to watch the PWMVVT channel. As you can see, it does do the "steps" as intended, but it's also seeing A LOT of noise, with huge spikes. I don't want to point at this being the culprit, as when we had the VVT unplugged, it was still getting the misfire codes. I will need to check back with Aaron on whether that's an issue or not. 

I did see that the LTFT_I was -116.00 and the LTFT_PL was -1.56. As I recall, that -116 is kind of high, so I will dig deeper into my search for a vacuum leak of some sort, I suppose.

8 minutes ago, Zappo said:

Are you sure you checked the COP harness thoroughly? I had a random misfire that I chased for months and finally narrowed it down to the harness.  I could get the miss at idle, lift the harness up and it would go away.

I've gone through it from ECU to coils 3 times. I did have an issue that dropped a cylinder early on, but that has been fixed. This car shows NONE of the obvious signs of a misfire. Idle is always smooth and it doesn't make a peep now. the CEL will come up a random times.

I could check things out by zeroing out the VVT map and see if the spikes are still there, and how the car reacts in regards to the misfire codes.

Edited by Chuck W
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22 minutes ago, Midnight Caller said:

Did you by any chance mess with the knock sensors ? Are they clocked right as in VIDA/VADIS ? Are they tightened to spec ? Maybe one came loose and gives false positives ?

The originals were installed on the replacement engine 3 years ago, when I dropped it in. The only thing I did for the COP install was add a harness, like I did for my car, but ran it along the outside of the stock raceway that runs along the subframe, etc. On my car, I was doing a manual swap at the same time, and was easily able to drop the new COP harness in the raceway. Over the 20-30K miles put on the car in those 2 years, there was only 1 or two misfire codes. That would be worth checking, however.

I'm still kind of looking at the VVT spikes. We ran the car with the code "active" but the VVT solenoid unplugged, but still had the misfire codes. I think I'm going to reflash with the VVT map zeroed out as well as unplugging the solenoid, just to try and fully rule that out. I'm also going to log it, to see if those spikes are still present. I don't have a bin that is just COP w/o VVT for this car (due to the special AC mods), or I'd just flash with that.

Still planning on digging into those high LTFT_I values too.

On another note, seeing as I'm kind of new to logging  with the M4.4, would the "XFALT" spark retard parameters give indications, perhaps? 


Edited by Chuck W
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OK, well after some emails with Aaron, it may be the result of the VVT controls on an auto bin and having the misfire detection routine enabled. Disabling the misfire routine also gets rid of the spikes. It also seems to get rid of the phantom misfires.

He's investigating some overlapping RAM addressing which may be happening in this configuration.

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Hello guys,

Short question for the +400HP dudes :D
From your experience, does 12.24ms load (on 650cc injectors, so a lower injector constant) + 540i BMW MAF (so also lower values there in the MAF map) would suffice for a GT3076 and a target of around 400HP ?
Now still on a 16T and greens, and 9ms load gives me around 270HP...
Do I definetely need the 24.48ms mod ?

Thanks a bunch !

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