After removing the S-AFC2 from my car and tuning with ECUFlash, I've been fighting a misfire (or boost cut?) at ~6-6.5k rpms. Below is a dataset from EvoScan and my PLX R-500 (AFR & GM3BAR).

I have the boost cut limit set at 315. The timer at 1500 ms.

When I changed out plugs (gapped to 0.022") to try and solve the misfire, I noticed the Magnacor wires did not fit very tight at the coil. However, I did not have any misfire problems before removing the S-AFC2. Not sure if anyone can interpret from this log.

The AFR's get lean, but I believe this is only after the misfire starts. Anyone else datalog a misfire with EvoScan?

The MAP log from EvoScan shows 328. Does this MAP influence the boost cut? Or is it the load calc number?


RPM AFR GM3BAR AirFlow TimingAdv KnockSum LoadCalc
2825 20.0 -10.5 69.19 27 0 -8.77
2826 20.0 -10.3 69.19 27 0 -8.62
2833 20.0 -10.5 62.9 27 0 -8.62
2829 20.0 -10.5 69.19 27 0 -8.62
2833 20.0 -10.3 69.19 27 0 -8.77
2836 20.0 -10.1 69.19 27 0 22.01
2829 20.0 -10.5 62.9 33 0 22.16
2892 20.0 -10.5 56.61 34 0 22.16
2828 20.0 -11.0 62.9 35 0 22.16
2875 20.0 -11.4 62.9 36 0 22.16
2837 20.0 -11.0 62.9 36 0 22.16
2826 16.0 -10.8 81.77 42 0 32.27
2814 13.5 -10.7 163.54 37 0 57.77
2899 12.5 -7.6 245.31 29 0 63.05
2817 12.4 -4.1 301.92 24 0 78.29
2897 15.4 -1.6 358.53 21 0 98.69
2954 14.1 0.8 408.85 19 0 111.63
2984 14.0 1.7 459.17 15 0 119.88
3077 13.5 3.4 515.78 12 0 129.14
3109 13.4 4.7 591.26 9 0 140.42
3210 13.2 6.8 673.03 7 0 152.75
3339 13.5 10.6 742.22 8 0 163.17
3373 13.6 11.5 792.54 7 0 169.34
3525 13.4 12.0 842.86 7 0 171.3
3643 13.4 13.6 880.6 8 0 174.16
3706 13.2 16.3 905.76 8 0 173.21
3886 13.2 14.1 924.63 8 0 172.16
4005 13.1 17.0 949.79 8 0 171.13
4054 13.0 14.7 968.66 8 0 172.16
4202 12.8 14.9 993.82 8 0 172.16
4292 12.9 17.4 1018.98 8 0 176.03
4345 12.9 15.2 1069.3 7 0 176.91
4484 12.7 14.9 1113.33 8 0 180.81
4532 12.6 15.2 1144.78 8 0 182.44
4684 12.3 17.5 1176.23 8 0 180.31
4854 12.2 19.0 1207.68 8 0 185.68
4922 12.2 16.1 1283.16 8 0 189.95
5076 12.0 17.2 1352.35 7 0 191.5
5249 11.8 18.4 1434.12 5 0 197.73
5296 11.7 19.3 1440.41 5 0 196.74
5489 11.5 19.0 1509.6 6 0 196.53
5655 11.5 20.8 1553.63 7 0 189.38
5720 11.8 20.2 1547.34 8 0 188.34
5900 11.8 19.1 1578.79 10 0 182.13
6024 12.1 19.9 1597.66 11 0 184.73
6116 12.3 20.8 1371.22 14 0 174.87
6309 12.6 20.0 1415.25 16 11 147.84
6466 13.4 20.0 1232.84 14 18 105.36
6508 14.4 19.9 1251.71 16 18 126.5
6772 17.4 19.3 1182.52 12 18 138.04
7134 18.3 16.8 1012.69 8 36 134.79

 

its the wires. the magnacor wires suck and dont fit well for our cars.
put the stock ones back on and you wont have the misfire.

 

I bought the car used, so I do not have stock wires. I plan to go purchase stock wires this week, if the price is not too ridiculous. I'm just not sure if it's coincidence that I did not have misfire problems before I removed the S-AFC2.

 

yes it is just a coincidence. you said it your self

https://www.evolutionm.net/forums/sh...d.php?t=189305

Stock wires are about $40+ from the dealer, or $35 plus shipping from buschur. good luck

 

First, change you plugs as Faisal has suggested. The stock one are the best.

Second, please tell us your mods so we can help you better.

 

looks like you are running way too lean. you are at 12:1 at 6000, and never reach 11:1 until 5200...

I would richen it up some. especially after 6000 rpm

 

Lean after 6k rpm is due to misfire (I believe). I agree, needs to be riched up a bit before then also.

 

Good lord, is that 13.1 AFR at 17psi and 12.2 AFR at 19psi I see?

 

My question is this. Are you reading knock as misfire? Or are you hearing the car misfiring and that is what you are basing that on?

To me, it looks like your running WAY too lean. It might be the plugs, but basic troubleshooting would tell me when you removed the s-afc, theres some dudes tune in that ecu that is way lean. They probly were using the safc to correct it. I would bet if you pulled your map, you would see some high numbers in the high octane fuel map. Those should be in the 9's or 10's in that load/rpm range if your running 93.

 

Razor its worse haha...check it:

RPM | AFR | BOOST
6508 | 14.4 | 19.9
6772 | 17.4 | 19.3
7134 | 18.3 | 16.8

DUDE 17.4 afr at 19psi OMFG boom haha

 

is someone gonna take the laptop and cable away from him?

 

Im in florida right now, maybe I should take a drive up to NC lol

 

I changed the plug wires, which did not solve the problem. Yes, it is running too lean. I thought the misfire was causing the leanness, but nope, I was wrong. It's tough to watch rpm, afr, and traffic when tuning by yourself.

I've added a lot of fuel up top, and still lean. Now I'm wondering if it's an issue with fuel pressure or if there's something very wrong with the tune. I've attached my high octane fuel map. Injectors are 680 cc's.. scaling of 650.

 

I think you have your injectors scaled wrong if that is indeed your high octane fuel map.

What type of injectors and what are your injector battery voltage settings? 650 sounds a bit wrong for 680's. My Denso 720cc's are set at 636.

 

razorlab - thanks for the advice. I think you are right. I was only going to ~6k rpms when setting up the injector scaling originally. But, as you can see in the attached graph, the AFR leans up exponentially after 6k rpms. Lesson learned!!