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idle tuning

Practical Dyno Tuning

Discussion and questions related to the course Practical Dyno Tuning


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Link to video: https://www.hpacademy.com/dashboard/courses/practical-dyno-tuning/step-6-idle-tuning-idle-speed-control-settings

at 0:47, what are:

1) idle ramp down delay, rate and limit

2) idle activate throttle pedal threshold and hysteresis

3) throttle pedal limit, filter, decay,

4) switch pullup control and threshold

at 1:26, you mentioned switching off closed loop control (is this the state of running of the engine i.e. when the engine is warm it runs closed loop and when cool it runs open loop?), when must we switch this off?

is the base position table the one at 1:43? what do the cell values represent in the table at 1:43? VE? throttle position?

I was looking at the mapping of a inline 6 engine running fairly aggressive cams and noticed that from idle, if I were to accelerate and when letting my foot off the pedal back to idle, the RPM dipped significantly (1.right before accelerating & 2. right before the RPM settled back to idle when released my foot off the pedal). Would this be due to the base idle position?

Note that all these parameters are only relevant for a MoTeC M1 so unless you're tuning this ECU they won't mean anything.

1. The idle speed will hold for a delay period and then ramp down to the target. this helps prevent the idle dipping and stalling

2. The throttle position below which the ECU will attempt to control idle speed

3. This is related to how the M1 blends the throttle target from idle when you move the throttle pedal.

4. Settings if an idle switch is used.

You need to disable closed loop idle control so that you can set the base idle position table properly. Otherwise the ECU will try and correct any idle speed errors. The numbers in the table are again MoTeC specific but essentially are a percentage of the max idle throttle opening.

If your rpm dips on throttle tip in it's likely to be accel enrichment that's your problem. If on the other hand the rpm drops when it comes back to idle then it's likely to be your base position values (or something else related to the idle control).

what is an idle switch?

by closed loop idle control, do you mean "the state of running of the engine i.e. when the engine is warm it runs closed loop and when cool it runs open loop"?

Ok, I am unable to find the accel enrichment and base idle position table on a Motec 100 series ECU. Can you advise me where to look under for these?

Would it be possible for me to ask you some questions related to the various mappings of the car if I uploaded some pictures it?

An idle switch is a switch that indicates when the throttle is closed and the engine should be returning to idle.

Closed Loop Control, is feedback from the Lambda/O2 sensor is used to adjust the fuel. Open loop is when the various tables determine the amount of fuel to be injected. In the MoTeC hundred series ECUs this is called "Lambda Control".

Have you looked under Adjust->Functions for features like Acceleration Enrichment and Idle Control?

Hey David, ill look under those and get back to you if I come across any further questions. Thanks!