Haltech Idle Control and Zero Demand Fuel

Hi all.

I am running a Haltech Elite 2500 on a pretty custom twin cylinder turbocharged engine. I am having a tough time with idle tuning.

1. The Zero Demand fueling changes based on when the engine is heat soaked or not. I do not have a good way to correct this.

2. Idle air is controlled with the electronic throttle body. I am having issues with it starting at much too high an rpm and then the engine surges as it idles down.

Any suggestions to help alleviate these issues would be great.

Thanks

First of all can I get a little more information about the engine and ECU configuration? What are you using for a load input? Does the engine use a plenum chamber? Are you seeing a stable MAP signal at idle?

I don't use the zero demand fuel table on anything I've tuned so it's hard to add too much here. You can add additional generic comp tables as you see fit to deal with aspects such as heat soak if you can't adequately account for this with the typical ECT/IAT trim tables. Admittedly heat soak is tricky to truly account for though.

If the idle speed is flaring too high on startup I'd suggest revisiting your idle control base values as well as the post start base offset values. It may be that the post start offset in particular is too high and resulting in the closed loop control causing the surging as the idle speed is pulled back down.

Hi Andre.

I eliminated the zero demand fuel control and added more magnitude to my IGN correction at idle. This helped tremendously. Thus far, this seemed to help with the heat soak issues, as I have a much more stable idle. Upon initial startup, I have no post start offset added and it still opens the throttle about 2% more than table value. Any ideas on why it is doing this?