hi does anyone know what idle up switch does? when i press it nothing happens, help, thanks, andy.
- (#9320) andy, 16 Mar 04 08:56
It's to increase tickover when the engine is under load from the aircon. Full explanation is in the archives
- (#9320) Ian Dunse (Derbs), 16 Mar 04 09:09
Hi All
I understood that the IUS was also to help warm up the engine in cold conditions and to keep heater system working when stationary and makin heaters more effective,it must be to speed up water pump to keep a fresh supply of hot water in the heaters
dennis
- (#9320) dennis, 16 Mar 04 10:12
"When I press it nothing happens" - yes, this is pretty common. As far as I can tell there are three separate "idle-up" systems. One when the aircon is running, one when the coolant is cold, and one from that manual dashboard switch. The aircon one and the manually-switched one separately feed vacuum to the same servo to act on the accelerator lever. The coolant-driven one acts independently.
I think not quite as Ian says, the manual switch should work even if the aircon is off.
So in cold weather the manual switch appears useless because the coolant-driven system is active until the engine has warmed up.
The solenoid-operated vacuum valves in the manual and aircon systems are interchangable (and expensive, £80?) I can't think why they put two in unless it's so, when one fails, you can rewire it to work fine on just one!
Does anyone find the switch really useful? I don't.
- (#9320) Dave (Sussex), 17 Mar 04 08:38
The IUS only raises the idle speed when the blower is switched on - if the blower is off the switch will do nothing,thats how it works on mine anyway.
- (#9320) pete, 17 Mar 04 13:41
The hand book states that the idle up switch is, "For use when warming up the engine. When not warming up the engine, have the idle up switch turned off.
Experience tells me that the quickest way to warm up a Townace is to drive it somewhere, so I have never actually used it on mine.
- (#9320) dave Bright (Bournemouth), 17 Mar 04 15:28
I've used it to quickly defrost/demist, with heated rear window on, from a cold start. In the summer with A/C on to cool the interior prior to passengers getting in. Not sure if that is how it is to be used but works for me.
- (#9320) Clive (Bristol), 17 Mar 04 15:45
Thanks Pete. Yes I meant to say that not having the heater fan switched on is another reason why "I press it (IUS) nothing happens". I presume that having either the front or the rear blower on enables it. With climate control and the blowers on Auto it may get more complicated.
Clive: as I recall it the A/C should fully activate the idle-up vacuum servo, pressing the IUS then should have no further real effect - but psychologically I agree it feels good.
- (#9320) Dave (Sussex), 18 Mar 04 02:19