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Issue with oscillating/bouncing idle when at operating temps

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12 hours ago, ClintBHP said:

Looking much better, now try this in the fuel map:


Screen Shot 2018-01-29 at 09.05.02.png

Carried out these changes! 

The engine did not appear too happy with them, as there was a lot of popping out of the exhaust almost immediately after I started the engine. It actually almost stalled out after the initial start, but caught itself. The events were such that I felt the need to take a log a few seconds into the cold start routine, as can be seen in Log 1. This was a few seconds after initially starting the engine.

I also found that the engine was very choppy and did not want to pull away from a traffic light as it would before we altered the axis of the fuel table initially. Almost as if it was too lean. I noticed this a little bit yesteray driving the car with the altered fuel map axes, and noticed it even more with the new fuel settings. This can be reflected in the logs as well, as I wanted to show what it was like driving around.

I would say that low throttle driveability (i.e. puttering around out of vacuum)  was a bit easier before we changed the scaling of the vaccum section of the fuel map. Perhaps it is something with how the ECU interpolated values after the change OR the tuner found the need to have the initial scaling as was because it improved drivability within the vacuum section of the map? I'm no tuner, so just guessing here and going off my 'before and after' driving observations.

Once up to temp, I'm not sure if the idle was any different from what it was on the previous map revision. I didn't really try turning anything on this time, as it seemed that the new driving behavior was more the star of the show than anything else.

Log 1 - started just after initial start when I noticed the exhaust was popping and banging,

Log 2 - wanted to display what happened when I went to take off from a stop. A lot of sputtering unless I gave a lot more throttle and slipped the clutch more.

Log 3 - idle 

Here are the logs and map:


Thanks again for the time you've taken to help me fine-tune my map, I'm very appreciative! :) 

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For quite a while I've had an issue with an oscillating idle especially during the winter months with a built Subaru application. We first came across it on my V88 ViPec ECU, but could not do too much

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It will take some tweaking, try these changes, the last log files were good, just keep them coming.

Your right we went too lean but the map adjustments on the Axis look good now just need to get the fuel map nicer, take a new set of logs with the following changes.



LINKECU FORUM TestMAP - 2.0.pclr

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15 hours ago, ClintBHP said:

It will take some tweaking, try these changes, the last log files were good, just keep them coming.

Your right we went too lean but the map adjustments on the Axis look good now just need to get the fuel map nicer, take a new set of logs with the following changes.



LINKECU FORUM TestMAP - 2.0.pclr

ClintBHP - tried the map, and it still pops and bangs while warming up...Not as badly as last time, but it is still definitely doing it. This time the log includes the entire cold start. Didn't go for a drive this time as it was still hesitating as I tried to move the car. Gentle free-revving at idle isn't occurring cleanly, unless I really put my foot in it to bypass areas of the fuel map that were changed. It overall sounds like it is running lean misfiring.

Link: https://www.dropbox.com/sh/ptk7wnzgyhxz8vn/AAAsLQt9W4KrHoJpChB35uX6a?dl=0

Tuning Question - What was the purpose behind us rescaling the vacuum section of the fuel map?

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In your original map the first 3 breakpoint -100 -80 and -70 were the same, your idle was at around -30 -20 -10 and you only had a breakpoint at -20 and -40 so we added in -30 and -10 to give better resolution.

Try this new map and send me a new log with both cold start and when warm.



LINKECU FORUM TestMAP - 2.2.pclr

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Tried these settings on Testmap 2.2... Less popping and banging going on, but still some. I took the car out on a drive, and noticed popping and banging while on the move at low throttle positions, and the car just overall not wanting to do much when in vacuum, and then there is the sound of what seems like a lean misfire that I keep detecting, almost as if the engine suddenly switches to running on 2 cylinders or something. It just seems to be running rough overall. It still doesn't really want to move from a stop again unless I try to bypass that area of the map.

Tuning Question - What would increasing resolution in the vacuum section do for the way the car runs?

There is a second fuel table in the map as well.... will this not have to be reworked as well like the main fuel table?




Thanks :)


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