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Bobec

Unstable idle after hot start

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Hello, I have attached a log file of a hot start showing a fluctuating idle speed before settling into a reasonable idle after around 10 seconds.

I could only suspect incorrect idle ignition control settings. Idle control is on open loop, car runs an e throttle.

If you could let me know what other information you would require please let me know. All new to me so hopefully the log file is acceptable. I can send a .pclr too if required.

Thanks - Rob

warm start 2.llg

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The one thing I notice is a large immediate  swing in your idle timing. It is bouncing directly from 0 to 15 at every fluctuation which could be either causing or exacerbating the surge. Have a look at your idle ignition settings and make sure it isnt kicking in and out of the idle ignition table and also make sure that the idle igntion table has at least somewhat of a gradual increase/decrease as well as the correct direction. It can be confusing if you are using idle target error as an axis. If you plug in your - and + numbers the wrong way it can cause instability. If you can post your .pclr I could have a look at the settings.

Blaine@Carmenaperformance

Edited by blaine@carmenaperformance

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I have a similar issue on mine and the timing is very stable at idle. It will rise and fall for about 10 secs or so then settle out and idle fine. Just wonder of its some sort of post start fuel/ign decay

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Timing at idle does not necessarily need to be stable. The idle ignition feature in the Link ecus is many times necessary to keep an engine stable at idle. Many times the IAC is not fast enough to counter fluctuations. If you have a surge at idle and are not using idle ignition timing I would recommend giving it a try. Bobec, you also may want to try adding 5% of fuel to the base fuel table in the active idle cells to see if it stabilizes. If it helps you can always alter your post start table to suit.

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Hi Rob,

Blaine is correct, your ignition angle is bouncing up and down and the main cause of this is that the ignition angle is mainly coming from ignition table 1, then the idle ignition table, then back to ignition table 1, the cycle repeats. I suspect that one of your lockout conditions for idle ignition control is being hit. If you could post your base-map as well that would be useful thanks.

Scott

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Thanks so much for the info guys, Actually yes it was originally hitting the the MAP lockout within idle ignition control @50kPa, I have upped it to 60 but may still be a bit close. Now I have a few directions to try I will see how I go.

Appreciate you mention the idle target error +/- I notice it is explained in good detail in help and it did take me a minute to get my head around it.

Basemap2.pclr

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Bumped up the MAP lockout figure and tightened up the idle ignition table and so far it is idling much better. Still plenty of room for improvement and I found quite a mismatch between the Idle ign table and main Ign table as shown below so seems there was always going to be a jump when transitioning between them.  Appreciate your help

Capture.JPG

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