The missus has a '99 1.4i Ibiza (gotta keep it VAG) and by and large it's been very well behaved. Anyhow, I was at a loose end last weekend, and instead of replacing the wishbone bushes (I didn't have a press) I changed the air-filter instead, as I had one for an intended service kicking around and getting in the way. After swapping the filter I didn't get a chance for a test-drive (standard practice for me) but the girl tells me today the car didn't feel 'right' on the drive to work. take it out for a quick baz and it seem to be holding the idle a lot higher than usual, tickover is over 1000rpm and coming off drive the revs climb to nearly 2K before dropping to 'near idle' On these little engines the idle is controlled via a servo on the throttle valve, so no ISV to prod, and now I'm kinda at a loss, do these ECUs adapt, is it just getting used to its new easier breathing filter? Or is there something else amiss? I checked the PCV hose connection again this evening - that's the only hose onto the airbox that I can think of. I don't have any diagnostic tools other than a timestrobe and a colourtune plug - I'm quite low-tech. Considering buying a fault-code reader, but that'll be another topic. Anyone played with these little cars, and know what the problem might be, or where to start looking? oh yeah, it's an APQ engine - same as the Polo
She got it looked at today by a garage with a regular/generic code-reader that's didn't find any fault codes logged. Would I find anything extra with VAG -COM?
ooh! talking to myself here, I know, but someone else may find this useful. Just found this on tyresmoke.net: Need to perform a throttle body adaption, done with VAG-COM, that essentially gets the ECU to cycle the throttle butterfly through it's full range of motion, and re-learn it's correct position. This is 'cos I cleaned the TB, removing some oily crud, when I changed the filter, the ECU had adapted to the crud, letting more air in to compensate for it's slightly blocked idle-path - which I've now unblocked. All makes sense now. There's also some muttering later on in the thread about an iffy water temp sensor that was also causing problems, so I may well get one of them too if they ain't too dear.
My old 99 polo 1.4 was similar, Idle/cutting out problems. Cleaned the TB and reset basic settings and we where away again.
Make sure you find out how to do the reset on the butterfly mate as my vag com skills don't stretch that far! Cheers, Mike
Just to follow up, whilst resetting the TB position helped, the car still wanted to idle at about 1800rpm when rolling- i.e. when coasting upto a junction - this didn't seem right still, so as per the thread on tyresmoke I also replaced the temperature sensor (12 -GSF) this evening (10 second job once you've cleaned the crud off it) and things are pretty much back to normal. There appears to be two distinct 'stationary idle' and 'idle when moving' speeds with these engines, I assume to give a bit of extra revs for the PAS, the stationary idle is now about 900rpm, whereas the moving idle is about 1100rpm - I can live with that. Worth knowing perhaps if you've got a car (mk3 golf, mk4 polo, mk2 Ibiza) with the 1.4 APQ engine.
awesome hints there, duly logged into my brain! my girlfriend has a 2000 biza 1.4, so i might have to do this one day too! I've already done the sensor as gauge seems to be playing up, didnt help tho
