Idle control valve question...

[Jim_rx7]

first of all, what exactly does it do?


With mine plugged in the revs shoot upto 3k when cold, then hunts from about  1500 to 2500.

With it unplugged it idles fine but to start the car you need to blip the throttle.

The car was mapped with the it unplugged. Is there a way to adjust the PFC with the idle control valve plugged in to sort it all out?

The car seems to start a lot easier with it plugged in.

[Eddie]

Hi

I do remember something about the pfc idle control under load settings I found on here but it never solved my problem, I even took the thing apart and decreased it as I read they can get gunk ed up, the thing worked as far as i could tell.
(need to get hold of another 1 to check but its worked fine without for well over a year)

Took it too pip when it was going to be mapped and this was the first thing he saw, i explained and showed him, unplugged idled nice, plugged in hunted like mad.

The short of it Pip could not solve the problem and mapped it unplugged, never had a problem.

Pip mentioned the PFC and mechanical ICV fighting against each other, like a tug of war. cars been fine with it unplugged.


Cheers

[Jim_rx7]

wondering why I need to blip the throttle when starting with it unplugged, yet it\'s fine if it\'s plugged in. Apart from the hunting.....

Anyone?

[Timmy]

I get this prob too, last time it was adjusted thought it solved it but it came ack the other day.

[Jim_rx7]

Can you adjust the idle control valve, or are you on about the PFC?

[Eddie]

Yes a little strange that 1, I don\'t need to blip the throttle at all, hows your cable tension on the throttle cable?


Is your idle adjustment screw fully turned in but if it was i would have thought you would not get it started, hmm not sure to be honest, I am sure someone with more knowledge will be along to help further.

however on further thought every time i go to move of form a stand still i have to blip the throttle or the revs drop a little.


cheers

[Jim_rx7]

the cable is quite slack tbh. Should I tighten it up so it\'s actually tight?

Idle screw (infront of throttle cable) is fully unwound.

[Eddie]

No dont think it needs to be tight, how throttle response?

idle screw under the elbow on the TB.

cheers

[Jim_rx7]

Throttle response is fine. I\'ve not touched the screw on the bottom of the throttle body, so couldn\'t say.

What should it be set like?

[Jim_rx7]

After posting on rx7club forum, it\'s possible that it\'s not actually the idle control valve but the acellerated warmup system valve.

With it connected, car starts fine 3krpm warmup by then idle hunts.
With it unplugged I have to blip the throtule to get it going. There\'s no 3k warmup and no hunting idle.

Any idea how I can have if plugged in, but without the hunting? Does something on the PFC need adjusted, or is it possible that the valve could be duff?

It was mapped without if plugged in.

[Jim_rx7]

Thought I would post some possibly usefull info from the rx7club where I\'m also discussing.


"When plugged in and working correctly, the ISC opens fully to allow extra air in on a cold start. It is effectively blipping the throttle for you, without moving the throttle plates. That\'s why it\'s starting easier.

Why is it surging and/or idling high? A few things cause that. The first is too much air getting past the throttle plates. For whatever reason, the PFC usually needs the throttlebody adjusted for less idle air in order to maintain a stable idle. There are half a dozen screws that control idle air when cold and when hot, but usually adjusting just one or two of them is all that\'s necessary. The second thing that can cause problems with the ISC being plugged in is not following the idle learning procedure, which requires you to reset the Power FC and lose all your settings (if you don\'t save them to a laptop with a datalogit box). I have never heard of anyone setting the idle on a PFC using the FSM procedure (jumpering TEN). The third cause of a surging idle is purely a mapping issue: a mixture leaner than about 13-13.5:1 (if you have no smog pump) can cause surging, especially on hot start when a heatsoaked air temp sensor leans the mixture out further."

So, I think now I\'m going to plug the valve in, start the car.. then adjust the idle screw under the throttle body to see if that makes a difference or not.

[DR SCHNITZEL]

I am havin this prob now. my revs stay at 2000rpm after fitting my aeromotive fpr and single tub. I too the plug off the IAC and it went down to 1500, hmm thats as low as it will go even after messing around with all the screws till im blue in the face.
 
I might try lowering my base fuel pressure. as its 40psi at startup. do you think that might work. im sure i have no leaks anywhere. Im stumped.

[bumpstart]

Hi

I do remember something about the pfc idle control under load settings I found on here but it never solved my problem, I even took the thing apart and decreased it as I read they can get gunk ed up, the thing worked as far as i could tell.
(need to get hold of another 1 to check but its worked fine without for well over a year)

Took it too pip when it was going to be mapped and this was the first thing he saw, i explained and showed him, unplugged idled nice, plugged in hunted like mad.

The short of it Pip could not solve the problem and mapped it unplugged, never had a problem.

Pip mentioned the PFC and mechanical ICV fighting against each other, like a tug of war. cars been fine with it unplugged.


Cheers

read my post concerning AWS ( at least as applied to the FC )
http://www.mazdarotaryclub.com/forums/showthread.php?p=606021&posted=1#post606021

[bumpstart]

-- AWS,, 17 secs of ABSV,,,, 60 secs of added mixture ,, 120 secs of retarded timing
and while the ASV is in operation,, the fuel pressure solenoid shows the reg full vac
( pressure is 36 psi,, and not 42 )


now,, you have a PFC
it runs the ignition,, and fuel,,
regardless of what the OEM ECU is doing to the fuel pressure solenoid
and regardless of what the stock ECU is also doing to the ABSV and ASV

the PFC,, is trying to chase a set point rpm,, with only the

BACv

so,, BACV goes nuts up and down in speed trying to cut the rpm from what the PFC believes is an overshoot

( when ,, in the factory AWS scenario,, it will have likely not been into closed loop,, or at least be closed looping looking for 3000 rpm,, and not 850 )