hunting idle sorted

[Eddie]

At last found the issue with my hunting idle.
Running Trust FM no cat, super dragger back no air pump, dash pot removed and greedy pullies installed with ac still installed I would experience really bad idle problems, got all the info on what it may be from the various groups, and went through various things one by one.
First off rats nest and valves, found a few valves at fault, and replaced the hoses I then sealed plenum and throttle, made sure all couplings to the IC were nice and tight.
Altered the PFC idle setting
But still-hunting idle.

Last thing was I hear a clicking from under the plenum, I then unclipped the idle control valve big cylindrical black thing on the back near the firewall and the idle went as steady as a rock, messed around witht he air bleed screw and got a nice steady idle only luctuates 10-20 rpm

So does anyone know if I am ok to leave this not connected or will it cause problems with anything else?


Cheers

[ianelvar]

I guess it\'ll just mean that the ECU won\'t have control of the idle speed. Nikp said he\'d had a similiar problem when I posted a question about hunting, so I guess it\'s a knackered solenoid in the valve. Annoying you have to take the extension manifold off to change the thing!

[Eddie]

Right I see now, so souldn\'t really cause any problems, would this make a differnce under load from the ac or heated rear seeing as the ECU is not controlling the idle?.

Sure I read you can carb clean the thing as gunk get it a little clogged,going to remove it and get it tested.

I can remove it without taking of the UIM as it sits behind the UIM near the throttle.

Funny thing is it worked fine before the PFC.

[stuart wizy]

hows it going eddie?
is the hunting worse when the cars started from cold or is it the same once the engine is warmed up.
have you checked compresion or do you have a boost gauge?
have u tried changing map sensor.
you can try mine on your car if you want.
I had a dodgy conection on mapsensor plug once which caused uneven rich idle.
you can do a sensor check on the power fc.
let us no if u want to try anything on ur car of mine.
cheers
stu

[nikp]

Yeah, i haven\'t run with the idle valve for over a year now. I tried it again on Friday when i had a nice steady 950rpm idle - as soon as it was plugged in the idle hunted! Removed the plug, and flat idle again. Stoopid thing!

I did try carb cleaner on it a while back, but to no avail.

[ianelvar]

I wonder if it\'s a duty cycle problem. Can you set the duty cycle in the PFC for that solenoid? I\'m wondering if it\'s set too high, and the thing opens too much, the PFC tries to pull it back down, closes the thing, decides to try again, and loops through the same sequence. I\'ve never used a PFC, so it\'s just a bit of a wild stab in the dark.

[Eddie]

Hi Stu
The car starts in cold start mode with no hunting what so ever, only hunts when up to temp.
Not had a compression test recently, have a boost gauge, and will be getting it MOT\'d this week so will check if its boosting okay.
Once its MOT\'d I will bring it round to show you.
Sensor check seems ok no problems being reported on the PFC.
It does run rich but I put that down the base map on the PFC, its going into pips monday for mapping

nikp  thanks for the info glad someone else is running without the idle valve connected, I also gave it a right good clean when my UIM was off.

ianelvar I understand you reasoning I was infomed by Efinisteve about something  like this, cant remember the values you can alter, from what i rember its a RPM setting in idle, if I find the doc I have I will put it up here.
In to WGT so I will be asking these questions to the PIP.

Thanks for all your help guys.

Cheers