santalars Posted October 23, 2022 Share Posted October 23, 2022 Is there any easy way to adjust the idle speed on a 3.5 efi? Car was idling at 800 rpm until I replaced the leads and spark plugs to the correct ones. Now its idling at 1200. I did the timing and the throttle sensors which were both completely off too. how can I get the idle speed down? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 23, 2022 Share Posted October 23, 2022 I would first check for a vacuum leak, any hose not replaced, or knocked or damaged will lead to this. 2 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 23, 2022 Share Posted October 23, 2022 The flapper setup has no active idle speed control as such - there's the warmup valve on the front that is a bimetallic valve heated by 12v, and ISTR the air-con models had a small solenoid that added a bypass into the plenum when the compressor engaged. If something's suddenly changed I'd check for vacuum leaks as Bowie suggests or other mechanical faults. Quote Link to comment Share on other sites More sharing options...
Escape Posted October 26, 2022 Share Posted October 26, 2022 There is a screw to adjust the base air bypass, near the throttle valve. But as above, first make sure there are no vacuum leaks or other faults (like the throttle not closing fully). Quote Link to comment Share on other sites More sharing options...
santalars Posted October 26, 2022 Author Share Posted October 26, 2022 I did check and can't find a problem with the pipes. I have the feeling that that was messed up a long time ago. The timing was completely out and as soon as I set it right I had a huge increase in power .... and the idle at 1200. I don't think it's the right procedure to retard or advance timing to regulate the idle speed. There must be a way to adjust the idle speed? I have attached few photos showing the set up. The only space where a hose could be missing is the bottom one at the vacuum membrane for the distributer. Thoe top one is ther and the diaphragm is ok / advance seems to work. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 27, 2022 Share Posted October 27, 2022 Idle adjustment screw circled - assuming everything else is OK: Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 27, 2022 Share Posted October 27, 2022 Of course if your timing was way out and causing low idle then it could be a previous tinkerer 'fixed' by turning up the idle screw.... If so you'll be fixing the fix Quote Link to comment Share on other sites More sharing options...
santalars Posted October 28, 2022 Author Share Posted October 28, 2022 Yep, fixed the fix. was way out. Running smoothly at 800 now witch correct timing, leads and plugs! I could not find it in literature and by inspection I thought this is just a hold down bolt for the inlet. Thanks guys! I'm member since over 12 years and whilst I'm only popping in for the occasional question it's so good to still have the same good people providing excellent advise. time for a donation. 3 Quote Link to comment Share on other sites More sharing options...
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