shane0569
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« on: September 10, 2014, 04:01:34 PM »
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Hey guys I really need some insight here.
I've been working on this car for some time now and I'm at the end of my own ideas.
It's a 2001 Audi A6 2.7T Auto.
Tune is unknown but not far from stock. Purchased the car with a tune in it, but the tune was only to delete O2's I believe. So, stock boost.
Car was purchased with blown turbos. Replaced those and spark plugs, timing belt...etc...
Now when the car is sitting in park, you can rev all you want and it never misfires.
When I drive it, I drives pretty good as long as you never put your foot into it. As soon as you push it to or near full throttle, it does this very odd sputtering hesitation, not really like anything I've experienced before. Really starts happening around 3k rpms. (Where boost would really start to come in)
I gapped the BKR7Es to .028 so it shouldn't be a gap issue.
I tried driving it with and without the MAF plugged in...didn't realy make a difference either way. (Maybe sliiiightly better without it plugged in?)
So, what would cause this weird sputtering/misfire/hesitation only while under load and not while just revving?
Please help me.
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shane0569
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« Reply #1 on: September 10, 2014, 04:40:03 PM »
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Oh and I forgot to mention that I boost leak tested to 20 psig as well.
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adam-
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« Reply #2 on: September 10, 2014, 05:15:20 PM »
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Can you get Me7logger working?
Could be a variety of things, throttle cut, a miss because of pinking, etc.
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nyet
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« Reply #3 on: September 10, 2014, 05:52:49 PM »
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No mystery. Typical misfire behavior.
Check plugs, ICM, coilpacks.
Log to find out which cyl (but be advised misfire detection may or may not get the cyl right).
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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shane0569
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« Reply #4 on: September 10, 2014, 06:03:07 PM »
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Thank you for the inputs.
I can def do some logging. Although it seems that misfire detection has been disabled by looking in VCDS. How would I re-enable that?
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ddillenger
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« Reply #5 on: September 10, 2014, 06:20:59 PM »
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It's probably only disabled at idle areas.
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Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience!
Email/Google chat:
DDillenger84(at)gmail(dot)com
Email>PM
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shane0569
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« Reply #6 on: September 10, 2014, 06:33:18 PM »
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It's probably only disabled at idle areas.
OK. I checked after a driver with many hesitations/misfires, and after under total, it said zero I think. Can it be disabled in the tune? I will check again tomorrow to make sure I am not in error. |
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ddillenger
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« Reply #7 on: September 10, 2014, 06:41:19 PM »
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Of course it can be disabled. Check NMIALU and NMIDLU
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Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience!
Email/Google chat:
DDillenger84(at)gmail(dot)com
Email>PM
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nyet
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« Reply #8 on: September 10, 2014, 08:05:00 PM »
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It doesn't matter whether or not you see misfire at idle. You are seeing misfire under load. Fix that first, THEN worry about misfires under idle (if you care).
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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shane0569
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« Reply #9 on: September 11, 2014, 03:58:57 AM »
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It doesn't matter whether or not you see misfire at idle. You are seeing misfire under load. Fix that first, THEN worry about misfires under idle (if you care).
There are no misfires at idle. |
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Lost
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« Reply #10 on: September 11, 2014, 05:18:42 AM »
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Are you getting enough fuel up too fuelrail?
Measure it as well
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digitalhippie
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« Reply #11 on: September 11, 2014, 08:42:10 AM »
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Misfires can also be caused by bad cam position sensor and/or bad cam chain tensioner. I just went thru this with my car... ICM delete, FSI coils, new plugs... still misfired on 4-5-6. New cam sensor, still misfires. Cam chain tensioners should be here tomorrow.
In some cases the tensioner's plastic shoe can break, causing the same problems. You can purchase JUST the shoes...
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shane0569
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« Reply #12 on: September 11, 2014, 10:18:47 AM »
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I will check fueling as well. Thanks.
Yeah, it just seems weird that it won't throw any codes...none.
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shane0569
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« Reply #13 on: September 11, 2014, 04:46:12 PM »
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Turned out to be coil pack(s). Thank you for the help everyone.
Next question...has anyone ever had to do rod bearings in this engine?
I'm not positive that's what it is, but after the engine warms up, there is a slight loose knocking kinda sound that I think is coming from the crankcase. Not very loud and not there when cold. And it also seems to go away when I put the car in gear. (loads up the crankshaft with a bit of back force I think)
I was considering other things, but I don't think it's cam chain adjusters.
Any ideas?
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nyet
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« Reply #14 on: September 11, 2014, 04:53:35 PM »
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There are no misfires at idle.
Sorry, i misread your post... thought you were trying to re-enable misfire detection at idle. |
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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