101 | Idle Speed Control Tuning Link G4+

Would have like to be at this one live but the joys of having to work.

How you you go about over coming a high current draw fan on initial start up but then only needs 1-1.5% DC when its up to speed? I have a 16" fan that when switched almost stalls the car but when it turns off the idle only jumps up 90 rpm. Fan step is set to 1.5% should i just increase the Fan step and let the closed loop pull it back down?

Once I cleaned the spark plugs it worked as it should. Having large injectors idling in the non linear area is not fun to get a happy consistent idle.

In some situations you're going to need to accept a bit of a compromise. If I had to choose between stalling and having the idle speed jump up a little high, I'd always choose the high idle. It should only be momentary before the closed loop pulls it back in line and you could also use a very aggressive idle ignition control to help.

After more playing I setup the idle ignition table as 3d using fan status on the axis, using more ignition angle helped. One day I'll look at getting a PWM controller for the fan. That way I can slowly ramp the load up and down.

After a lot of head scratching trying to improve the idle i looked at a PWM option. Come across the below. Works like a charm, idle is so smooth only way you know the fan has started is because of the noise.

RS Stock No.418-3610

http://au.rs-online.com/web/p/soft-starts/4183610/?searchTerm=418-3610&relevancy-data=636F3D3126696E3D4931384E525353746F636B4E756D6265724D504E266C753D656E266D6D3D6D61746368616C6C26706D3D5E283F69292852537C5253207C52532D293F5C647B337D285C73293F5B5C732D2F255C2E2C5D285C73293F5C647B332C347D2426706F3D313426736E3D592673743D52535F53544F434B5F4E554D4245522677633D4E4F4E45267573743D3431382D33363130267374613D3431383336313026

Glad you got a solution to your idle problems. Out of interest are you using the fan step up to increase the idle position when the fan switches in and out?

Yeah the more I increased the fan step the higher the idle would flare up after the low dip. When I run the motor without the alternator belt and using another car as the alternator feed the rpm was stable. The Spal fan on initial start-up draws over 100 amps. With all the others electrics the alternator must of been stalling the motor.