Syvecs Forums

My NA car has a TPS primary load and I am using the MAP as a secondary load in order to handle idle control. This is because when the idle control valve opens and closes to keep idle, it change the AFR. So I am compensating with the secondary load.
I have currently set the Time blend to 20% for the off throttle region and then adjusting the secondary load map. This is working fine however I have basically got it working through trial and error and don't really understand what the time blend actually means.

I assume it is some sort of ratio between the primary and secondary loads but I am just guessing.

Can someone shed some light on this please?

What kind of air valve, the system is equipped? Maybe valve control parameters needs to adjust - as you mentioned that AFR changes. Additonal air volume needed through the idle valve is quite small - as the engine is running almost without load - internal friction, alternator load etc. are quite small.

Well I had to install a Bosch idle control valve from a 316 bmw, the fact is that the AFR is changing and I am assuming it is due to the idle valve not being completely stable.
I really want to understand how the blending is working, I have it all running stable AFR now and so it is fine.

You will need to add an anti fly-back diode with that idle valve otherwise the response is massively non linear to PWM duty cycle, which may be your main problem if you haven't.

Thats interesting, I have not used one of those before. Because I have converted from a three wire to two wire, I am using a voltage regulator to drive it but I will look into using this diode.

Thanks.

You're using a variable regulator?? Hmmmm, but why?

Supply the +VE side of the valve with battery 12v and connect the -ve side of the valve to a PWM output from the S6 (fuel or aux) and use a diode accross the valve with the cathode (bar end) to the +ve side and the anode to the -ve side.

If you are using a regulator then you probably won't have the problem as much as it's a linear device that probably won't be pulsing at the same 1Khz drive voltage. Having not tried that I can't say what the effects will be, but I would add a diode anyway.