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Old 04-21-2012, 07:53 PM   #1
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Default Car bucks between 2k and 2.5k rpm

So i havent ran my car for about a week now... Today i start it up everything was normal. At 2k it started bucking bad...BAD. I ran a log, everything is fine but the afr ratio goes in the upper 20s where the wideband cant read it. As soon as i go over to 2.5k or over everything is back to normal and the car runs perfect. I've checked the standalone and everything looks good (no weird dips in the fuel map). To make it work i had to bump up the fuel up 25 points in efficiency (90ish) between 2k and 2.5k rpm to bring my afr down to normal. This is all kpa between that range, not a specific cell. When i shut it down a little less than a week ago it was running perfect.

The log is all normal except the afr. Everything is within range...
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Old 04-23-2012, 11:42 AM   #2
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No one has any ideas where to start looking?
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Old 04-23-2012, 12:23 PM   #3
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post log of event.
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Old 04-23-2012, 03:06 PM   #4
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Here is a log, you can see over 60kpa between 2k and 2.5k it goes crazy lean. At first it's the map that worked perfectly last Sunday (not yesterday) Then i started enriching the cells at 2 and 2.5k to make up for it but there is still a random cutout at about 2.2k It's almost like it stops tossing in fuel at that rpm regardless of what the standalone does.
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File Type: csv 4-21-2012_1832.csv (585.8 KB, 95 views)
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Old 04-23-2012, 03:41 PM   #5
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its almost like the more fuel you add, the leaner you go.

no freaking clue.
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Old 04-23-2012, 03:44 PM   #6
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Check the ground at the front of the engine, check TPS, are you still running EGR? If so, see what happens when you unplug it.
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Old 04-23-2012, 03:54 PM   #7
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Ground at the back of the engine you mean? behind the turbo? Will check the other 2 now.
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Old 04-23-2012, 06:07 PM   #8
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So I checked the TPS... no different, i unplugged it, car couldn't rev above 1500 rpm. I unplugged the map, the car barely ran and then died when i plugged it in.

I checked the ground.. it's good. Reset everything by unplugging the negative from the battery for 30 seconds.

Checked the ECUs, everything is plugged in.

I checked all the connections to the map, all good also.

Where is the EGR plug? I looked behind but all i saw was the metal pipe going over between the manifolds. Is it that mitsubishi plug?

If memory serves me right i think it was raining the last time i ran the car.
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Old 04-23-2012, 08:20 PM   #9
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No, I mean ground at the front of the engine, to the mechanics right of the throttle body.

If you're looking at the EGR pipe, where it enters the intake manifold, the valve attaches to the intake manifold just a few inches closer to you. I'm holding a '00 EGR valve in my hand right now, the electrical connector attaches to a grey plastic piece atop a cast assembly. The top of the plastic piece is a circle, the bottom, where it attaches to the cast portion with four phillips head screws, is square.
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Old 04-23-2012, 08:27 PM   #10
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And empty the water out of the cylinder 1 spark plug hole
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Old 04-24-2012, 11:37 PM   #11
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Checked all cylinders, theres no sign of any water. Unplugged the egr plug, no difference. the cut felt a bit higher. Usually it goes up to 2.4k rpm, now it felt like it went after to about 2.6k but it may be my mind playing tricks on me. I unplugged the turbo so i'm now running on an open wastegate. cut starts at about 2.1-2.2k, not even on the 2k cell.
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Old 04-30-2012, 06:35 PM   #12
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So about 70 miles on the new tank of gasoline 94 octane... no change. the spot is still there. When the car is cold its a bit higher at about 2.5k and then as it warms up it becomes less noticeable at ~2.2k. I guess i'll be pulling injectors soon.
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Old 05-05-2012, 10:29 PM   #13
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if it keeps adding fuel and reads in the range where the sensor can't read anymore its possible its overfueling and causing the bucking situtation. I didn't check the log(s) but you could try leaning it out and see what happens as well.
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Old 05-05-2012, 11:27 PM   #14
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Well, yesterday on my way home from the gym it was bucking as the normal condition, halfway home it stopped and hasnt bucked since. AFR is currently 10-11 on the cells where i enriched it up. So wtf it's back to normal and the problem isnt there any more. I didnt do ---- to it but burn up half tank of fresh gas. It wasnt overly rich though.
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Old 05-05-2012, 11:34 PM   #15
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datalog?
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Old 05-06-2012, 02:04 AM   #16
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Log is all normal. just loaded my original tune and it runs perfect...It's like the leaning issue never happened. The thing is even before the log was all normal besides the afrs going full lean.
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