Well, I got my latencies dialed in. And my car is misfiring pretty much constantly in low load (cruise and idle)

If I get into boost the misfire goes away. What could be causing this?

Car is an 03

Mods are:
Exedy Twin
FIC 1450's
Kelford 272's
Helix 3" Downpipe
Greddy Ti-C cat back
3" testpipe
ETS 4" FMIC
Hallman MBC at 22 psi
Omni 4 bar MAP sensor
Walbro 255
Apex'i Turbo Timer
Innovate LC1 wideband

The car didn't misfire with my stock injectors, but as soon as I installed these, it sputters like crazy.

I've changed plugs, and it didnt help.

I also just filled up with my first tank of e85 in hopes that it was just to large of an injector on 91. But, to no avail, it still misfires.

I read somewhere Appauldd had this issue too, I pm'd him on what he changed but he hasnt gotten back to me.

So i'm asking the tuning community as a whole, what steps would you take to track down this issue?

My scaling now on 91 is:1329
e85:1170

Latencies:
2.784
2.122
1.680
1.296
1.104
0.984
0.816

Any help is appreciated.

 

if its sputtering like that, that tells me your deadtime (latency settings) are wrong. does it sputter when you rev the car up in neutral?

also you cant be guessing scaling size, you gotta log mid fuel trim and fine tune it.

 

Can the latencies still be off if the Trims are ok?

**Edited**

 

absolutely.

 

Opps, I meant to say the Trims. But I was thinking about what you said about scalings lol

 

fuel trim LOW yes.. can show good when its really bad. fuel trim mid = no.

 

Super..... lol

 

did they come with a card showing the deadtime tables? they should have.

when you rev your car in neutral does it break up also?

 

yeah they came with the card, it doesnt really break up when i rev it, if I remember correctly, i'll verify with you on that asap

 

I used the values for the open time on the card they came with, and it still did it.

The flow numbers at 43.5 psi were 1444 1440 1440 1440 too

 

Thats a large injector set for your setup.

First, make sure you have drained all the e85 outand replaced with 91-93.

Log your STFT/02 feedback, low and mid trims (LTFT), tps, ipw, idc, Air Flow HZ, 1 byte load, AFR MAP, WB02, RPM, timing, MAP sensor, batt voltage, coolant temp, air temp, and the kitchen sink.

Idle for a bit to get useful trim data on the logs. Start from a clean ECU with no trims if you can (unplug the battery for a bit). Cruise around making sure you create the problem toalso get data on the logs.

Basically you probably are way rich and the ECU is taking away fuel at open loop, but can't compensate quick enough when needing to add fuel during tip in/throttle changes due to the off whack trims.

If you post logs, there should be some tuners out here that could easily point you in the right direction. Good luck man and happy new years.

EDIT: Just took a look at my previous roms with smaller injectors....your latencies seem pretty high for use with a EVO ECU. Please check your latencies and try again.

 

On my Injector Latency Data sheet for these injectors it says:

..........................................10 volt 12 volt 14 volt 16 volt
Opening response time (ms) 1.68 1.38 1.17 0.98
closing response time (ms) 0.99 1.00 1.01 1.02

If that helps any, I tried it at these settings and still was getting that misfire I described, i'm going to dive back into it tomorrow and see if I can make any progress, it was driving a ton better on the way home tonight.

Still had misfires here and there, but definitely a lot smoother. I didnt change anything either, so idk