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Knox

Strange misfire

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Hello everyone. 

Yesterday I tuned a Link atom ecu on Mercedes 190 chassis with sr20det engine. I didn't swap it one other mechanic swap it and tune it first. When I tune it there is no misfire and everything is smooth. The issue occurs after fast gear change. Let me explain more on tuning I told to owner put 3rd and make a pull from low revs till limiter and there is no misfire but when after I finish the tuning on the road let's say owner make a pull at 2nd gear (no misfire any rev range) and put it 3rd gear fast engine misfire for a second and gone I mean misfire stop and engine revs like a champ. I tried to lean it and gives more ignition advance (because ignition is safe side first place) and did not sort the problem. Owner says with other guys tuning its much worse so I tought I touch what is the problembut I can not find it. Ignition coils are audi r8 red coils, stock ignitior removed coils directly wired to ecu. I also tried to add more dwell time to coils. I tried at 14v 2.2-2.3ms at high revs. 

I'm also adding calibrations if someone can check it, I will be happy. 

SR20DET.pclr

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It will be best to do a PC log to try to capture the event, then we will have some clues to work on.  https://www.youtube.com/watch?v=_P1LRANeO4A

There are possibly a couple of clues to problems in the ECU statistics.  It shows you have hit the MAP limit 12 times (boost cut), it also shows injector duty cycle is way beyond 100%.

2n8r4mt.png

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On 5/29/2019 at 12:21 PM, Adamw said:

It will be best to do a PC log to try to capture the event, then we will have some clues to work on.  https://www.youtube.com/watch?v=_P1LRANeO4A

There are possibly a couple of clues to problems in the ECU statistics.  It shows you have hit the MAP limit 12 times (boost cut), it also shows injector duty cycle is way beyond 100%.

2n8r4mt.png

I change map sensor location (tried to cancel vibration), I measured voltage at idle for coils and they are ok 13.7 volts,  I cleared statistics because of engine tuned from an other guy before so I want to have clear statistics. I have 3 log files and I attack calibration again with small changes. 

SR20DET.pclr Misfire Issue 2 Log 2019-05-30 11;53;21 am.llg Misfire Issue 3 Log 2019-05-30 11;53;21 am.llg Misfire Issue Log 2019-05-30 11;53;21 am.llg

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Did the car misfire during any of those logs?  The only thing I see is you are hitting the RPM limiter at the end and holding it on the limiter for quite some time.

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2 hours ago, Adamw said:

Did the car misfire during any of those logs?  The only thing I see is you are hitting the RPM limiter at the end and holding it on the limiter for quite some time.

Yes all logs engine misfires around 1 second right after gear change. Let me explain how its been. Push at 1st gear tyres starts to spin (drifting because of rwd) so hit the rev limiter and hold  1-2 seconds change to 2nd gear and misfire for 1 second after that misfire stops and tyre start to spin/drift again. This is same if you push at 3rd gear and change to 4th gear even if its not drifting.

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In all of these logs you are still bouncing off the RPM limit after you change gear.  In the pic below the dip in the blue TP trace is your gear change, you can see the RPM limiter is still acting after that for some time.

You either need to increase your limiter or turn on the advanced limiter settings and increase the exit decay rate so that the limiter is removed quicker after RPM drops.

25roacj.png

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On 5/31/2019 at 6:54 AM, Adamw said:

In all of these logs you are still bouncing off the RPM limit after you change gear.  In the pic below the dip in the blue TP trace is your gear change, you can see the RPM limiter is still acting after that for some time.

You either need to increase your limiter or turn on the advanced limiter settings and increase the exit decay rate so that the limiter is removed quicker after RPM drops.

25roacj.png

Everthing is perfect but I forgot to write here. And also I want to ask what is the highest exit decay rate I can use ? I used 20 but can I use higher like 40-50 is it safe ? 

Edited by Knox

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Everthing is perfect but I forgot to write here. And also I want to ask what is the highest exit decay rate I can use ? I used 20 but can I use higher like 40-50 is it safe ? 

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