S3c Throttle Butterfly Hole

[Mark67]

Hi. I'm still trying to set the S3c idle up and check for air leaks but wondered if anyone knows if there is supposed to be a small hole in one of the throttle butterflies? As detailed in an earlier thread mine had a self tapping screw in it. When removed it idles faster and remained lumpy. When replaced it idles lower & still lumpy! A ford site says this is to provide minimum air when the ICV is closed. Any ideas which is correct? Cheers

[Skinne01]

I have an S3c and recently had the hoses off the front to check whether the throttle was opening fully and it the drivers side butterfly valve had a hole in it.

[Mark67]

Thanks for that. Much appreciated. Will take the screw out and re-set. Give us as shout if you need to borrow a fault code reader if you haven't got one!

[tel595]

I'll be working on two of them all day tomorrow so will check...

[Loach1]

If you unplug the idle control valve, does the engine keep running at a very low idle? That's usually the goal when setting the idle baseline with the ICV disconnected.

[Mark67]

I set the TPS to 0.6v via the throttle stop & it seemed to idle ok when cold at about 1000 rpm with the hole in the butterfly, but when it warmed up it idled at 1600 rpm!

[Mark67]

I set the TPS to 0.6v via the throttle stop & it seemed to idle ok when cold at about 1000 rpm with the hole in the butterfly, but when it warmed up it idled at 1600 rpm! The ICV doesn't seem to do much and is new & the voltage supply is ok.

[Griffinr]

Mark67 said:

I set the TPS to 0.6v via the throttle stop & it seemed to idle ok when cold at about 1000 rpm with the hole in the butterfly, but when it warmed up it idled at 1600 rpm!

If you set the TPS using the throttle stop you're also adjusting the butterflies. I think the TPS has slotted holes and can be adjusted separately. When I had idle problems on my S3 I had to get the butterflies fully shut or it idled too fast. I think the ICV controls all the air at idle.
Rob.

[Mark67]

Hi Rob. I loosened the bolt on the roller on the throttle stop so the butterflies remained closed then adjusted adjusted the roller. Cheers Mark

[Griffinr]

Mark67 said:

Hi Rob. I loosened the bolt on the roller on the throttle stop so the butterflies remained closed then adjusted adjusted the roller. Cheers Mark

The roller controls the second butterfly, I think the first one is direct on the throttle shaft, unless the S3C is different.

[Mark67]

Will check, but is there a hole in one butterfly? Cheers

[Loach1]

Griffinr said:

The roller controls the second butterfly, I think the first one is direct on the throttle shaft, unless the S3C is different.

Are you sure? I thought the same, but on my car both butterflies are on the same shaft. The throttle lever is the only thing on the front shaft, both butterflies are opened by the shaft with the bearing attached.

This throttle body has one butterfly with a hole in it:



Usually to set the base idle, unplug the ICV and adjust the throttle stop until the engine almost stalls. Plug in the ICV and it will take over control. Engine should be warm btw.

[Mark67]

Thanks for the reply and photo. The hole in the butterfly looks a lot bigger than the one in mine. Is it off an S3?

[Mark67]

Just taken screw out hole and warmed up, tried to set idle but with ICV disconnected it idles at 1600 rpm. I guess I must have an air leak somewhere? Will try and make or borrow a smoke tester.

[Loach1]

The pic was just a random pic from the web, I believe it's from a 2.9 Granada. It does sound like you have an air leak, and the ICV should not be able to reduce that - it can only increase the air flow by-passing the throttle body. Check the vacuum hoses - there aren't very many. A leak between the air flow meters and the throttle body would lead to rough running, but not a high idle.

Keep us posted - you're getting close.

[Mark67]

I've booked it in for an air leak test with a smoke tester at my mate's garage on Friday as I can't see any cracked hoses etc and the carb cleaner trick didn't work!
My only concern is I've set the ignition to 15 degrees btdc as per granada manual for a 2.9 cat & I did read that too much advance can cause idle hunting! Do you think this is too high? It also hesitates occasionally at 2000 rpm or lower when cold and warm! Cheers