PWM idle control with large cams?

[ion332]

Ok, for some reason, I can't get my MSnS to control the idle properly.

My car has to idle at around 1700rpms to be able to make enough hp to deal with the low inertia and low hp at idle due to the cams.

Here are the settings I am using:

idle valve frequency:40
cranking(dc): 37
minimum:0
closed:0

fast idle(lower) : 65
slow idle(upper): 180
fast idle speed: 1700
slow idle speed: 1700
tps thresshold: 40
idle activation adder: 1200
dashpot settle time: 1
dashpot adder: 4

deadband range: 40
upper limit: 200
lower limit:70
fast recovery:14
slow recovery: 25

closure speed: 1
startup delay: 0

Now, my car at idle is sitting at around 55-60kPa. I don't know if there is a hardwired kPa upper limit that would disable the idle control.

I can turn on the pwm valve by putting the *closed* value to about 100, then I can hear it working. So I know my wiring and everything is correct. When I do this, I see the idleDC guage move to whatever the closed value is.

Anyone have any ideas? I am really at wits end here.

[superchargingmachine]

Just a couple thoughts, Dashpot settle time almost always has to be 255.

Is the valve physically large enough to flow enough air for that RPM? If closed = 100 and cranking(max) = 100 doesn't get you over 1700RPM the answer is no. Open the throttle valve so if you have an adjusting screw to say 1400-1500 and just let the idle valve add air to get to 1700. Cranking needs to be able to go above 1700RPM. So if Cranking = 37dc =1700RPM make Cranking = 40-45 The minimum needs to be whatever dc gets you just below 1700(1500-1600maybe)

The dashpot adder adds the 4dc at setpoint RPM + Daspot adder activation RPM, 1200 seems high. I use 200-400RPM.

Make sure TPS threshold is above your actual closed TPS value or things will act crazy.

I use larger Fast and Slow recovery numbers but those should get you bouncing around the setpoint.

[ion332]

Just a couple thoughts, Dashpot settle time almost always has to be 255.

Is the valve physically large enough to flow enough air for that RPM? If closed = 100 and cranking(max) = 100 doesn't get you over 1700RPM the answer is no. Open the throttle valve so if you have an adjusting screw to say 1400-1500 and just let the idle valve add air to get to 1700. Cranking needs to be able to go above 1700RPM. So if Cranking = 37dc =1700RPM make Cranking = 40-45 The minimum needs to be whatever dc gets you just below 1700(1500-1600maybe)

The dashpot adder adds the 4dc at setpoint RPM + Daspot adder activation RPM, 1200 seems high. I use 200-400RPM.

Make sure TPS threshold is above your actual closed TPS value or things will act crazy.

I use larger Fast and Slow recovery numbers but those should get you bouncing around the setpoint.

Ok, firstly, what is dashpot doing whereby it needs to be set to 255?

And, no, I don't believe the valve is quite large enough to correct maybe more than around 200rpms or so, so, yes, I will have to set the idle to around 1600 or so, then, I will have to set the idle to 0, and then hopefully it will be able to correct. So far, the best it can do with the AC and all accesories on is maintain about 1k, which isn't bad, but, with these cams, the car doesn't run very smoothly at all.

I will go ahead and adjust the dashpot to around 400 to see how it works.

And, I set the TPS closed to around 80, normally it sits about 73 or so.

Good news is, the idle works! Bad news is, its not quite large enough, but, hey, there are other ways around that. ;) My first solution is prlly to run a bosch fast idle solenoid in addition to allow bypass air to get by. I will run another relay off of the AC clutch on circuit, and run that relays output to the bosch. That will do much to keep the idle in range, then the PWM idle can just fine tune the resulting idle.