Can anyone shed some light on how to adjust the throttle closed switch on a ABF engine. I have tried searching but can't find much info on the actual procedure. Also the EVAP Valve in the engine bay should this make a ticking sound? The GF's MK4 one ticks quite loud where as the one in my MK3 doesn't make a ticking sound at all.
Any Ideas. My thinking was that when the throttle is on the stop it should only just click the switch. Mine seems to be too close and touches before the throttle is on its stop.
the evap thing should tick, but mine has never ticked quite like a mk4 as for the throttle, it can be a bit of a ball ache. i read on autodata years back about adjusting it. apparently you adjust the throttle 0.1mm or something daft from the full closed position. i dont think ive ever been able to get it right. too closed and the throttle sticks shut. too open and the idle is high i was thinking about adjusting it so that the throttle is closed with a strip of paper or something in there so it doesnt close fully and then tighten it up
My EVAP valve thing doesn't make a sound. I think it may be dead. Can i run the car with the Vac pipe blocked off at the throttle body to see if it makes any difference? I have read about using a piece of paper also on another website. When i done my MK2 8v i used a feeler blade as described in the haynes book of lies but the MK3 Book of lies has no info on adjustment. The switch on mine is pressed right in (if you know what i mean) when the throttle is closed where as i think its only meant to only just click when closed.
the switch is only glued onto the metal plate so i doubt its mm perect etc. i ran mine for ages with the evap nipple on the throttle body blanked off, i cant remember why, but it made no difference with it connected or disconnected. its only aim is to keep a vacuum in the tank and prevent fuel vapour getting into the atmosphere.
the switch it glued to a plate, with is screwed to the tb and the plate adjusts. the plate is basically the "back stop" for the throttle
I see now. Just been trying to work out why my MPG has been a bit down recently. Normally get about 39mpg on way to work but have recently been getting about 32-33mpg. Took sparks out last night and they are a nice tan colour.
yeah the switch should be plastic welded to the metal plate. the metal plate is often glued on as well as held in place with a screw. tricky to pop them off! anyway, here is the proper VW procedure for setting the idle switch adjustment: boom
Good discription although not everyone has access to those tools. It is really easy to to if you understand the basics and what the ECU is trying to do via the ISCV, target RPM and read rpm. The plate is held to the throttle body by a 5mm star screw. As Matt said loosening this will allow the base idle to be adjusted. You need to set the base idle,by revoling the paltecam to around 900rpm w/o switch connected then reconnect. This will reduce the ecu chasing the target idle as the ISCV responds. When the base is set too low the you have hystheis and hunting. Too high and the the rpm takes too long to return to target. This same principle can be used on other VW vehicles that have a PID idle speed system with a thorttle stop.
You should not have to remove the throttle body.This in situ on vehicle. Regarding the VAG settings you have to also take into account wear on throttle timble and cam over a 10 year+ period. So it is better to go by the tried and tested RPM method. This is what I found with these engine over the years anyway.
can do it without taking it off, just measure from the edge of the intake boot connection. As per the adjusting guide all you do is back off the switch completely and measure it, then set it so the new figure is what you measured + 0.5mm. or -0.5mm in this case
Would this explain why when i have to make a quick dash out of a junction when i depress the clutch the revs stick for a few seconds then slowly drop to 1800 then drop down to normal idle?
Correct. Over time the plate cam and plastic throttle arm get worn and move away from base settings. Also oil flim build up on throttle throws off the actual throttle opening area. All these factors have an effect on how quick the ECU can achieve/over achieve target idle.
What other problems would be associated with an incorrect switch position. Thanks Toyotec you seem like a genius to me with ECU settings.
I have this problem too, I noticed over the weekend that the throttle cable is half frayed, ie only half of it is still attached, could this cause the throttle switch to activate too soon, because the throttle spring on the side of the TB returns about 1mm too far (due to the cable extending a slight bit further cos of the fraying) ? Otherwise, it is adjustment time as you guys have described, as well as a new throttle cable!
I think I have this problem, the car seems to draw too much air into the ISV and the the switch is clicked off too early (looking at it).
Does anyone have a layman diagram, for eijits such as myself to follow?! Once Ive fitted my new throttle cable this weekend, if it hasnt made any difference Ill be attempting to adjust as you guys mentioned above.. I dont really understand, what is the paltecam?! and all the other big words Also, where abouts is the EVAP thingymyjig you keep mentioning!?
The EVAP Valve is bolted to the drivers side front strut tower. Can you tell me Dennis if yours makes a ticking noise when the engine is running?
