Floating idle

[cTc]

Hi all!

Engine 1.3, EFI

When the engine is warm, it sometimes happens that floats idling. All consumers disconnected.

I guess that the reason is an air leak, or a bad vacuum line. Or somewhere clogged.

The question itself that is usually the cause of floatingidle, which is in the first place to check.

As far as I know, there is no idle valve, and the air flow is regulated at idle I do not know.

Thanks!

[mikeand]

Mine sometimes dips down really low. Ive just chalked it up as a festiva thing

[TominMO]

Not a Festiva thing, most likely cause is a vacuum leak (in cTc's case anyway).

[cTc]

There are thoughts which hoses to check?

[Bert]

My car developed a loping idle at one time. Adjusting the dashpot plunger setting corrected the problem. I cringe at the prospect of trying to replace the air hoses on a Festy. But take heart an Aspire B3 has twice as many.

[jbibb1]

Is there a dashpot on an EFI car? I thought those were only on carbs for throttle return? If you're looking for a vacuum leak use starting fluid and spray it in a given area and listen for rpm to raise. Wherever the leak is it will suck in the starting fluid and raise the rpm

[crazyrog17]

There's an idle adjustment screw under a rubber cap to the right of the intake tube. That manual adjustment should be made with the idle programming terminal grounded (idk the real name for it, but it's a single wire connector by the brake booster).

The idle is controlled by the ECU via pulse width modulation to a solenoid valve. The valve is the IAC, idle air control. It has a blue top and sits behind the left side of the intake manifold.

If you've already checked for sources of leaks, make sure your VAF isn't sticking and rotating freely. Just pull off the intake tube to the air box and push it around with a pencil's eraser. If your car is missing or stumbling at all, it might be time for an ignition tune up.

[jake88maro]

There certainly is, on the left side of the throttle body, there are plenty of threads on adjusting them for proper idle ect. My DD 1993 has had an idle surge problem since i bought it, no real harsh side effects, i also just chalked it up to be a festiva thing because this is my third one that seemed to do it.

Is there a dashpot on an EFI car? I thought those were only on carbs for throttle return? If you're looking for a vacuum leak use starting fluid and spray it in a given area and listen for rpm to raise. Wherever the leak is it will suck in the starting fluid and raise the rpm

[FestYboy]

to make things clear, please post a picture of your engine. I suspect that your engine intake system is different than ours, and we can then point to areas to consentrate your efforts.

[cTc]

It is a wise idea
soon will make photo

[cTc]

Photo

IMG_3137.jpg IMG_3138.jpg

[FestYboy]

sweet!!!, your engine is EXACTLY like ours, this makes things very easy to deal with.

[cTc]

Ok, and what do I clean / check? :-)

[FestYboy]

sorry, only had time to post that before i had to skip out.

now to also be clear, does the idle drop, or raise on it's own? and is it consistant in that direction? if the idle drops consistantly, i would look at your throttle plate for debris and take 1/4 turn OUT on your base idle screw, and make sure there are no crack in the intake tube between the TB and VAF. if the idle rises consistantly, spray arround the vacuum hoses with carb clean and listen for the idle to jump. then repair the leak.