Bender Posted November 18, 2020 Share Posted November 18, 2020 So lately one of my Supra (5speed NA) start developing that strange problem every time when i change a gear revs go up to around 3k rpm and then go back to normal. Also what i found out if i press the accelerator revs also back to normal. Very strange as car was driving perfectly fine week ago... I just changed fuel tank cover but it got nothing to do with that. Any ideas guys? Quote Link to comment Share on other sites More sharing options...
rider Posted November 18, 2020 Share Posted November 18, 2020 I've experience that on my old MG when it had a sticking cable. Try a blob of grease at either end. Quote Link to comment Share on other sites More sharing options...
Bender Posted November 18, 2020 Author Share Posted November 18, 2020 20 minutes ago, rider said: I've experience that on my old MG when it had a sticking cable. Try a blob of grease at either end. I got that feeling something can sticking thanks will try that Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted November 18, 2020 Share Posted November 18, 2020 (edited) Had this issue on my TT6 a few weeks ago, throttle cable casing was perished, most likely the cable itself was damaged after 26 years.. Replaced the cable, all good.. Edited November 18, 2020 by Samurai 20V (see edit history) Quote Link to comment Share on other sites More sharing options...
Bender Posted November 18, 2020 Author Share Posted November 18, 2020 1 hour ago, Samurai 20V said: Had this issue on my TT6 a few weeks ago, throttle cable casing was perished, most likely the cable itself was damaged after 26 years.. Replaced the cable, all good.. Thanks will look into that Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted December 2, 2020 Share Posted December 2, 2020 Throttle body probably worn, air leak somewher, or TB adjustment, which is tricky and time consuming. Also block off the PCV valve and see if it cures it, they can leak...Have fun, the issue can be expensive to fix if it's the TB, as most are now worn. Quote Link to comment Share on other sites More sharing options...
mplavery Posted December 6, 2020 Share Posted December 6, 2020 (edited) On 11/18/2020 at 8:19 PM, Bender said: Thanks will look into that Yea on my TT6 sometimes the throttle doesn’t shut completely.. doesn’t go as high as it’s but if I blip it it goes down again .. I think the throttle cable might need changing If I use it more than a day it goes away.. think it where I just don’t use the car anymore Edited December 6, 2020 by mplavery (see edit history) Quote Link to comment Share on other sites More sharing options...
Bender Posted December 6, 2020 Author Share Posted December 6, 2020 On 12/2/2020 at 2:12 PM, Chris Wilson said: Throttle body probably worn, air leak somewher, or TB adjustment, which is tricky and time consuming. Also block off the PCV valve and see if it cures it, they can leak...Have fun, the issue can be expensive to fix if it's the TB, as most are now worn. Thanks i got spare throttle body in garage somewhere which i bought 2 years ago so i guess will change that Quote Link to comment Share on other sites More sharing options...
Bender Posted December 6, 2020 Author Share Posted December 6, 2020 8 hours ago, mplavery said: Yea on my TT6 sometimes the throttle doesn’t shut completely.. doesn’t go as high as it’s but if I blip it it goes down again .. I think the throttle cable might need changing If I use it more than a day it goes away.. think it where I just don’t use the car anymore That could be the thing as got few Supras and lately dont use that one much Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted December 7, 2020 Share Posted December 7, 2020 On 12/6/2020 at 2:51 PM, mplavery said: Yea on my TT6 sometimes the throttle doesn’t shut completely.. doesn’t go as high as it’s but if I blip it it goes down again .. I think the throttle cable might need changing If I use it more than a day it goes away.. think it where I just don’t use the car anymore I had this issue recently, throttle cable solved the most part of the issue, the other issue is the dashpot. This is a little damper that helps close the throttle smoothly. It seemed stuck, gave it a few pumps, seems fine now.. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted December 7, 2020 Share Posted December 7, 2020 It doesn't really HELP closure, the opposite in fact, it slows closure by adding resistance. Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted December 8, 2020 Share Posted December 8, 2020 Yes, agreed Chris. I meant it helps in that the close is not abrupt. In my case, it was jammed, so holding the throttle open at 1.3% (Reading from TPS on standalone), and causing the idle to stay high. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted December 8, 2020 Share Posted December 8, 2020 If the TB is worn and leaky blanking off the PCV valve can help reduce closed throttle air flow, but you need to vent the grommet in the cam cover to a pipe and catch tank as it will emit some oil droplets. I remove the PCV on all my long term car engines as inhaling its own fumes is bad for the engine, (although venting them to atmo could be said by the Greens as being bad for the environment. Your call on that...) The price of a new TB may help you decide though Quote Link to comment Share on other sites More sharing options...
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