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Reply to "Fuel Injection and Electronic Ignition for VW engines - Speeduino Style"

Ok, so I did just a little more fiddling with the idle air control and thought I'd add it to this thread in case anyone is foolhardy enough to take the same path. Idle air control is the fuel injection equivalent of a carburetor's choke.

It works by leaking extra air and fuel into the intake manifold at certain temperatures and for certain amounts of time after startup. It can also maintain a set idle speed. The particulars are set in setup tables. The mechanics involve a valve that can be controlled by the speeduino (or other ECU) and the setup tables.

I used the same Bosch 3 wire idle air control valve that I had used on my old Porsche turbo. In this case, it was a $28 Isumo equivalent I found on fleabay

https://www.ebay.com/itm/Idle-...&epid=1659374567

The connections are simple. One wire is connected to a fused +12v and the other two wires are selectively grounded by the Speeduino through the Idle 1 and Idle 2 connections. One opens the valve and the other closes it.

Screenshot_20210226-175913

I made a small capped manifold out of PVC pipe that connected to 1/4" NPT barbed fittings placed into the intake manifolds. The other end of the valve has a small air cleaner attached.

PXL_20210227_033415027PXL_20210227_033456177

I'm using PWM Closed + Open Loop as the idle control type. Each system is different, but if you go down this route and have questions let me know. I went this way not only to get a smooth startup, but to keep the air conditioning compressor from dragging the idle down at stops. Works great for both purposes.

Cheers!

Mike

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Last edited by Michael Pickett
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