Sickkkkkk

 

Video from last track day:http://www.vimeo.com/14021015#

Car got a little mis-fire that would start half way through a session. Not exactly sure what's up with it yet. I turned the boost down from 28 psi to 26 psi after the first session and added .3 point of fuel out the top. It seemed to help a little, but the misfire would still show up from time to time. My check engine light came on at the end of the day for a bad front O2 sensor, so maybe that was a factor. My plugs were brand new NGK BPR7ES , first time at the track on them gapped at .022" - so that wasn't it. Maybe the engine got a little hot, although the water temps stayed normal between 200-210 the whole time....

Any ideas kids?

 

Funny, I just switched over to e85 recently and was at BWillow Raceway back in June for 2 days and I got the same thing, a Front o2 Sensor code. No misfires from what I am aware of, but I was not data logging anything though


huh....

 

My 02 sensor has over 100k on it, i think it just wore out, not related to the e85.

I was datalogging everything but AFR and it looks good. I feel like it's heat related, like plug wires being old and increasing resistance at high temperature or something like that. My plan is to replace the O2 sensor, check the tune with some street pulls and just keep running. If it happens again at the track I'll be watching AFR's this time.

 

Well, I replaced the O2 sensor, that fixed the CEL.

BUT - I drove the car to work today so I could make some tuning pulls and see what's up with this mis-fire and check the AFR's. The AFR's look good, right around 12.0 which is spot on for E85. I typically run 11.8 at the track and I think the local station is up on percentage vs when I tuned the car last. But still 12.0 although higher than my 11.8 track tune target is not the cause of this mis-fire.

All the logged inputs look good, AFR, timing, boost, airflow. Yet the car gets a serious stumble-pop mid pull.

I'm thinking it's ignition related. Going to try and borrow some coils or something and trouble shoot. I hate this crap! I was planning to do a track day next week, but I won't have enough free-time to resolve this issue before then

 

I have my stock coils if you need to borrow/buy them Jared, just lmk. And I would talk to Aaron about what you could possibly do with my stock coils and your issue, although it could be completely unrelated to what I am suggesting. LMK if you need/want them.

 

Tested some other stock coils - seemed to help. Still might try some COP units as a final test.

But it's started raining in the North West, looks like summer is over. The car might just roll into the garage for the winter pretty soon. Hopefully it will roll out in spring with a cage, no-misfires, lower weight, and some shiny Girodisc two-piece rear rotors.

 

I agree....my spidey senses say summer is over. I have some cool lightweight parts we need to discuss!

 

First off thanks for posting your E85 map (and the other guys that posted in the "E85 timing maps" thread). Between all the maps I used the most conservative timing numbers to write the starting map for my E85 3.7L Stealth. Jared, your map was one of (if not the) most conservative in my spool up area (my boost ramps fast from 3900-4500) so I'm pretty much running your timing in that area.

What I found was I would have a massive mis-fire/stutter as soon as the boost hit hard (4500-ish). Good AFR's (12.0-12.2) and about a 90% chance of it happening just the same. If I got past that RPM/area I was good. If I leaned it out to 12.8-13.0 it happened alot less often but still the majority of the time. Even though I was running non-projected plugs (R5671A-9's) I was thinking pre-ignition from the plug ground electrodes since there's plenty of opportunity for that with such little advance so I swapped to these:


Those are R7118-9's (they really don't match up with 2003+ Evos). They fixed my issue completely. Not a misfire since and completely smooth.

Now I'm not sure why you went from not having an issue to it rearing up but I can tell you that those plugs were a 100% fix for me.

I did some digging and it looks like there are no "level" plugs for evos like the one I have (unless you count the rotary / surface discharge types). Looks like you guys have to run the ones that look similar (IE a straight ground electrode attached to the edge of the plug) but they're slighly angled out into the combustion chamber. Here's the best part numbers I found:

Evo 8's:
NGK R6252E-9 (Resistor)
NGK R6254E-9 (non-resistor)
Denso IW01-27 ($$$)

Evo 9's:
NGK R7438-9 ($$$$)
Denso IKH01-27 ($$$)

If the 9's are too cold you can drop down to 8's (or 24's for the Densos). There are alot of Evo 8 plugs to pick from with that design (those aren't the only ones) but the Evo 9's are severely limited to just those two part numbers (which are big money).

I hope that helps!

 

For me the main thing is that the car has been running well on this ignition setup for a year now at this power level. So my cheap NGK BPR7ES plugs can get it done, and I have new ones installed right now - with the issue. So I think it's coils. Or some stupid boost leak I can't find. FYI... rain is full-on in the NW now.

 

Hey. I didn't read all 50 pages of your thread. Lol. But I did read the last one. I have tuned a hand full of evos and I've had a couple of them call with this problem. I had them regap their plugs down to a smaller gap. If you haven't tried that you definitely should. If you have. lol sorry for not reading the other pages. Good Luck!

 

looks like my upcoming build but i have a 35r glwb bro

 

I did have the issues when I first turned the boost up to 28 psi at a gap of .028". But since then I've been at .022" gap and have been great. Until now, and I've tried .020" without luck.

Mostly I've been busy playing/building guns and ignoring this car recently

 

I had an Evo VIII with a nine turbo not pushing near the boost you are and he ended up where you are now. Thats where it finally stopped misfiring. So you're pushing more boost you might try a smaller gap.... Lol. It would be a cheap shot.

 

Hadn't bought any parts for awhile - so I fixed that. Anyone spot the new goodness?



Going to drive it to work tomorrow and see if things have improved with the misfire. I also realized that my battery is really shot. It will only hold a charge for a few days at a time and has been drained to dead way too many times in it's 5 years of duty. So I ordered a new PC680. I'm about 13% sure the battery is a factor as well.

Close-up of this action... I'll probably open the gap back up to .025"-027" instead of the .022" I'm running now. I may even go back to stock $10 a pop Iridium plugs



Next up should be some new rear rotors....