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Idle speed dipping drastically after throttle blip

Link G4 Plus Software Tutorial

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Trying to nail this down. Idles fine but if I blip the throttle it will come down very low or even stall. Sometimes it hill hunt until it can stabilize.


You'd be best to post up some screen shots of your idle settings. There's many reasons why you may be experiencing this. One of the common reasons would be a base duty that's set too low.

You really need to attach the tune and a log for proper help. A few things that I see in your screenshots that are not normal and may be contributing.

RPM lockout should be more like 300RPM, with it at 500, the idle control will kick in too early (500rpm above target) when the engine is slowing down, so the ECU will start to close the throttle. Then by the time the engine is at correct speed the throttle will be too far closed and you will get undershoot.

AP lockout should be more like 0.5% so its not trying to control idle while you are driving.

Your idle base position & throttle target arent set up correctly, the top row of the E-throttle target table should be set to allow the engine to idle without any idle speed control enabled. The base position table is used to only to increase that for warmup. So the idle base position table should have numbers near zero in the normal operating temperature range. The main target table needs bigger numbers so the base position table can be smaller. Have a look and the mini base map as an example.

idle ignition control is also very important with e-throttle cars so thats why we need to see the tune and log to confirm it is working correctly and how it is configured.

Also, make sure you are on the latest firmware (5.6.7), there are several fixes for E-throttle idle control in that.

files attached

Attached Files

I should also note this is only a issue at a stand still not moving. Coming back down while moving is rock solid. Car also has a large cam for the motor tvs 900 etc. Far from stock.

putting e throttle mode to open corrects it but want to obv run closed

so lowering rpm lockout to 150 has fixed the lope but its still trying to run on a bit after key off

Its Dieseling on when key is cut. I dont know if i need to pull fuel. When I tuned the stock DME there was a shutdown even section not so much here that I know of.

From the log it appears your dip is caused by a couple for factors meaning the CL trim was winding up trying to control idle when the engine was outside of what would normally be considered idle conditions. The RPM lockout that you picked up on was one of them. A RPM lockout of 150 you may find a bit too tight but if it works then fine.

My suggestion would be to adjust these 4 settings in red to match this example:

Oh, and your Pedal position sensor needs calibrating, it is reading 0.4% at rest so you will need to fix that for the settings above to work reliably.

For the dieseling I answered on your post on the Link forum. As far as I can see from the wiring in your car when you turn ignition off the power to the ECU, injectors and Ignition should all be cut at the same time. So fuel is still getting in somehow. It could be a leaky injector or it could be some wiring change that is causing a back feed somewhere and keeping something partially powered up.

Its bizarre I can throw the stock DME back in and the dieseling does not occur.

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