j-16 1 Posted January 10, 2007 Hi, I've got a bit of a problem with my mi16. When I blip the throttle the revs rise but then hang and take a few minutes to slowly drop back down. Does this sound like the ICV or possibly a sensor? The throttle butterfly isn't getting stuck, my throttle cable is newish and i don't think i have an air leak. Cheers, James Share this post Link to post Share on other sites
dee205 3 Posted January 10, 2007 Do you mean it revs up to say 3k and then drops off completely to near stalling or drops down to 2k and then slowly to 950-1k As far as I know sound ecu's hold the rev drop slighty at around 2k and eases it down to idle. This is what mine does anyway. It's very good idle control that stops the stalling effect the 8v engines can suffer from My ecu number ends in 355 Damien Share this post Link to post Share on other sites
saveloy 8 Posted January 10, 2007 It is quite possibly a worn air flow meter. Share this post Link to post Share on other sites
j-16 1 Posted January 10, 2007 Sorry badly explained. When i depress the throttle peddle obviously the revs rise...but when it's released instead of quickly dropping back to idle they just stay where they are - at say 3000rpm. After a few MINUTES this will eventually drop back to idle. Occasionally if the revs are stuck and I poke the throttle a couple of times the revs will drop down to where they should be. Cheers for the ideas. Share this post Link to post Share on other sites
jackherer 543 Posted January 10, 2007 it'll be a worn throttle body I reckon, I've seen it a few times on Mi16s. Share this post Link to post Share on other sites
j-16 1 Posted January 10, 2007 As in the butterly sticking or the flaps for the chokes? Share this post Link to post Share on other sites
jackherer 543 Posted January 11, 2007 I think it might be to do with play in the external linkage between the two butterflies but I'm not sure TBH, I just put different TBs on. They are getting rare now though as they are all knackered so in future I'm considering fitting a VAG TB as described on the main website, I don't believe they give any power advantage but at least they wont have any play. Share this post Link to post Share on other sites
saveloy 8 Posted January 11, 2007 Aaaagh! Well, why didn't you say?! Yep I agree, knackered throttle body. I've just changed mine. I had the exact same symptoms. Check the spindle for play. Share this post Link to post Share on other sites
Pugnut 9 1 Cars Posted January 11, 2007 I think it might be to do with play in the external linkage between the two butterflies but I'm not sure TBH, I just put different TBs on. They are getting rare now though as they are all knackered so in future I'm considering fitting a VAG TB as described on the main website, I don't believe they give any power advantage but at least they wont have any play. yeh the top linkage is usually fine, its the linkage for moving the bottom butterly that gets pretty worn . easily fixable by fitting an extra spring and/or making a new bracket/roller for the bottom part .Mine snapped once leaving the bottom butterfly full open which made for a pretty interesting drive home at full tilt Share this post Link to post Share on other sites
pug_ham 244 3 Cars Posted January 11, 2007 I had this on one last year, everything was smooth except the linkages on the TB were occasionally jamming as it had been rebuilt incorrectly so it kept getting stuck. I rebuilt the TB so the butterflies opened in stages & its been fine since. (well it was until the lighting loom decided to smoke so its been waiting a new loom since). Graham. Share this post Link to post Share on other sites
Higgy 0 Posted January 11, 2007 As far as I know sound ecu's hold the rev drop slighty at around 2k and eases it down to idle. This is what mine does anyway. It's very good idle control that stops the stalling effect the 8v engines can suffer fromMy ecu number ends in 355 Damien I remember when Anthony was looking at my Mi, and he thought that the mine with Motronic & knock sensor (i think ...355 ECU) seemed to hold the revs longer. Also when I start my car the revs go to 2k then slowly drop down to idle. Hanging revs makes 'blipping' on a downchange smoother Higgy. Share this post Link to post Share on other sites
j-16 1 Posted January 20, 2007 Balls. Just removed all the induction pipes to take a look at the chokes. There's no play at all between the butterly and the chokes - feels very tight on boths so I guess this is not the problem. It seems like more of an electrical problem rather than mechanical, maybe I'll try my spare ecu then a spare ICV. Cheers for the ideas Share this post Link to post Share on other sites
j-16 1 Posted January 28, 2007 Just tried cleaning my ICV with a mixture of petrol, degreaser and WD40 - now the engine will start as normal followed by the revs steadily rising to a 3k idle! Unplugging the 2 pin ICV causes the engine to stall. Does this mean I've completely ruined my ICV and it's time for a new one? Share this post Link to post Share on other sites
Ryan 99 Posted January 28, 2007 Check that the idle switch on the throttle body is working. If the switch doesn't get pressed when the throttle is closed then the ECU won't know to use the idle valve to regulate revs. It's most likely that either the switch needs rotating slightly, or the pins have pushed out of the plug. Share this post Link to post Share on other sites
j-16 1 Posted January 28, 2007 Think the idle switch is o.k - this has just happened since I tried to clean the ICV because the revs were hanging. Cheers Share this post Link to post Share on other sites
