andenbre

iTrader: (4)

Ok, I have started 2 other threads on other topics with absolutely no response. Hopefully I will get some feed back with this problem. driveability ....... what I have going on is a misfire/misfire like condition between 2000 and 3000 rpm. It does not happen under full throttle but under 80-90% throttle in 4th 5th 6th when pulling from 2000 rpm. I noticed it happening when I aborted a pull to check spool up. if I retard timing it is worse. I have pulled my plugs and they look ok. wires have no carbon tracking.

has anybody else seen this? it seems to happen most during the spool up spike in psi but not at wot,just the 80-90% range, I will post logs tomorrow after reassembly

jcsbanks

With the spec you list, a standard ECU should run without misfire, so I don't think it is an ECU map issue, unless the JDM MAP sensor is giving readings your US ECU still doesn't like in some way?

C6C6CH3vo

iTrader: (9)

Are you getting a 0300?

Diverter valve malfunction can occur in those conditions

andenbre

iTrader: (4)

no p0300 code. it kinda sounds like a pop out the exhaust. I have seen many cars that will trip misfire codes for odd reasons and when there is an actual hard miss it wont pick it up. I am going to log today then try putting the stock sensor back in and see what happens

bvdawg13

iTrader: (3)

are you sure its not just fuel cut?

dan l

iTrader: (3)

What is your air/fuel ratio when this happens.

andenbre

iTrader: (4)

when looking at these logs, the sections of log that show afrs spike to 17-19 to 1 as the throttle is being released are areas where this miss fire is felt, it seems to only happen in the 2-3 k areas while boost is above 10 psi. if you look the 2 byte load will drop 60-80 load points while manifold psi does not change. i think this shows the weakness of using a calculated load instead of a map based load like jdm. this also shows the significant effect of tps to the internal load calculation

I realize I forgot to log idc I will do a couple tomorrow with it

andenbre

iTrader: (4)

this almost seems like a fuel cut at this point

matyb

iTrader: (1)

not being fecious...

plugs $1.50!!!

i learned real quick to keep like, 12 on hand at all times... if you think you may have a plug problem you throw new plugs in and eliminate them. just try'em

simple
easy
cheap

andenbre

iTrader: (4)

unfortunately plugs for the 9 are not as commonly available as the 8. they range from 50 to 150 bux a set. I don't think its the plug due to the fact that this happens under specific load and boost conditions and when ecu load drops while manifold psi remains the same. the symptom does not present its self when load and manifold psi maintain steady relative readings.

Also do to a work related injury money is a bit tight and if it turns out to need plugs the car will more than likely sit until I am back to work

Mr. Evo IX

iTrader: (5)

I agree 100%, most likely plugs or your spark being blown out due to excessive gap. But your saying it doesnt do it at WOT? My plugs were doing that and I think they were a little fouled. I just discontinued tuning for a while because I was going to order some new plugs but after a week of normal driving the issue went away. Seems like lots of WOT 3rd gear runs foul the plugs out.

andenbre

iTrader: (4)

I will drive it normal for a few days and see if its better. the plugs looked good when I pulled them and that was my initial suspicion...that or a coil craping out. however it only occurs between 2&3 k with partial throttle coming off full throttle. just a stutter/pop for a split second, just enough to notice. and there is the occasional slight hiccup in that range during normal driving that is just enough to make you think "hmm, was that bump in the road or a miss?"

wrcwannabe

iTrader: (1)

I had a similar miss on my 05 MR VIII Changed the plugs ( the installed ones were the copper type heat range 7 ) to the Iridium ones heat range 8 Problem went away.

I dont beleive the IX plugs would be any different than the VIII ones . You can check with Buschur about that though. I got the Iridiums from Rock Auto for $32 shipped for four

Milburn

Planet Evo

Can I ask a stupid question??
Why on gods green earth are you doing full pulls in 4rth, 5th and 6th from 2000 RPM?!
Being that at NO TIME whatsoever will you ever see this range of rpm on the street, strip or anywhere unless you shift at 2000 in every gear. If you plan on smashing the gas I would hope that you would downshift to a healthy rpm first.

Planet Evo

What is your AFR right before the full tilt downwards?