Degsy Posted March 2, 2022 Share Posted March 2, 2022 Problem: When we rev the engine and leave to drop to idle it drops to around 1300 RPM. If we grasp the throttle unit and apply a little pressure it seems to drop the revs to 950/1000 RPM? See attached video. Action taken by ourselves; We have thoroughly cleaned the throttle body, ICV, new plugs fitted, all hoses checked. Question: Anyone any idea what could cause this problem? and how to resolve it. WhatsApp Video 2022-03-02 at 15.09.09.mp4 Quote Link to comment Share on other sites More sharing options...
evinX Posted March 2, 2022 Share Posted March 2, 2022 Probably due to wear in the butferfly shaft or try a bit or carb cleaner. Lots of na owners suffer worn throttle bodys. Pmd Quote Link to comment Share on other sites More sharing options...
Degsy Posted March 2, 2022 Author Share Posted March 2, 2022 evin x carb cleaner where? Quote Link to comment Share on other sites More sharing options...
mc92 Posted March 2, 2022 Share Posted March 2, 2022 I've had one where the brass butterfly piece wears itself into the side of the throttle body. If you shine a light down the throttle body you may be able to see. I think it's a bad design. Quote Link to comment Share on other sites More sharing options...
evinX Posted March 2, 2022 Share Posted March 2, 2022 36 minutes ago, Degsy said: evin x carb cleaner where? Pull of the plastic intake and give a little spray of carb cleaner in there incase the butterfly is sticky Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted March 2, 2022 Share Posted March 2, 2022 Check the throttle cable is not worn out, also a sticky dashpot(damper) can cause high idle. I experienced both of these issues. 1 Quote Link to comment Share on other sites More sharing options...
m12aak Posted March 2, 2022 Share Posted March 2, 2022 (edited) Yeah as @Samurai 20V said. I had a similar issue, it was the dashpot as it was old and dirty. Some WD-40/penetrating oil to clean it out fixed it, I just cleaned the 'piston' and left the cap/filter alone. I have a spare to hand so I took a photo of it just in case you weren't sure what it was (when I first heard the word I didn't have a clue lol) Edited March 2, 2022 by m12aak Added more info (see edit history) Quote Link to comment Share on other sites More sharing options...
Degsy Posted March 2, 2022 Author Share Posted March 2, 2022 Great i will give this a try many thanks i will let you know 1 Quote Link to comment Share on other sites More sharing options...
Degsy Posted March 3, 2022 Author Share Posted March 3, 2022 Sorted it after many attempts to adjust the setting on the dashpot (and removing and refitting the Throttle Body assembly) we decided to leave it off. The idling now goes down straight away to a sensible 950/1000 RPM. Is it recommended to replace them with a new one or will it have any long term damage without it being fitted? If anyone has a part number it would be appreciated Thanks for all your help. D. 1 Quote Link to comment Share on other sites More sharing options...
evinX Posted March 3, 2022 Share Posted March 3, 2022 33 minutes ago, Degsy said: Sorted it after many attempts to adjust the setting on the dashpot (and removing and refitting the Throttle Body assembly) we decided to leave it off. The idling now goes down straight away to a sensible 950/1000 RPM. Is it recommended to replace them with a new one or will it have any long term damage without it being fitted? If anyone has a part number it would be appreciated Thanks for all your help. D. Your idle should be around 750-800 on a NA 1 Quote Link to comment Share on other sites More sharing options...
m12aak Posted March 3, 2022 Share Posted March 3, 2022 2 hours ago, Degsy said: Sorted it after many attempts to adjust the setting on the dashpot (and removing and refitting the Throttle Body assembly) we decided to leave it off. The idling now goes down straight away to a sensible 950/1000 RPM. Is it recommended to replace them with a new one or will it have any long term damage without it being fitted? If anyone has a part number it would be appreciated Thanks for all your help. D. No problem, however, as evinX said, it seems there is another issue at play here in addition to the sticky dashpot. I have no idea what the long term effects are when you don't run one, but I'd personally persevere and try and sort the one you have (Toyota would have included it for a reason), as the part number is 22202-46060, but it appears to be discontinued. To be honest from how the dashpot appears to work I would be very surprised if yours could not be saved, as I said all I needed to do to get mine back and working properly was clean it and ensure the piston moved freely (it may be easier to do this off the car). also, have you run through the diagnostic procedures listed within the Toyota workshop manuals? Maybe the ICV isn't working within spec? Also make sure all vacuum lines are routed as OE. It looks like your one that should come from the charcoal canister and then through a check valve into the top of the throttle body (iirc) is capped off. I have no clue if that would cause a high idle, but to rule that out I'd look at reconnecting it. Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted March 3, 2022 Share Posted March 3, 2022 How is the condition of the throttle cable? If the insulation is perished, more than likely the cable is frayed.. This was the main cause of my idle issues. Of course, I had made sure the idle valve was working properly at first. 1 Quote Link to comment Share on other sites More sharing options...
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