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Had car out last night for run up the glens and noticed my idle speed started to creep when the car gets hot....it's about 900 when cold but as it heats up it creeps to about 1200 doesn't (so far) go above about 1200...any help appreciated ,

 

Regards

 

Jas

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Do you set the idle speed when the engine is fully warmed up , if not try that first.

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The idle speed has been fine but I can't adjust the idle back any more, would air leak not show up when cold as well though?

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  • 5 years later...

Wanted to start this back up again and hopefully get a little bit more insight. Not sure if you found the source of the problem @jas?

Recently purchased a ‘76 TR6 and I am having the same issue. The hotter it gets the more the idle speed creeps up. Again, starts off around 800/900 and after a couple of short trips ends up idling around 1800 rpm...

 

any thoughts/suggestions would be great-thanks! 

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Start by making sure all the butterflies are closing properly, the CR throttle linkage can be a pain to set correctly as there is a degree of twist in the linkage  from where the cable attaches.

Having got them all to close properly you should then be able to set the idle speed with the air bleed screw. then all you have to do is get all three sets to open at the same time as well, best of luck!

Neil

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On 5/18/2014 at 5:40 AM, jas said:

The idle speed has been fine but I can't adjust the idle back any more, would air leak not show up when cold as well though?

That road is very wide, but very short. :-)

Edited by John McCormack
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Have you checked your manifold vacuum at idle? I use a vacuum gauge on the brake booster line. I know from decades of measurements my engine has to have 10 inches of mercury at idle on the airscrew. If I can't reach that level with the idle air screw I've got a leak somewhere.

Note: my engine has had a lot done to it over the years- your engine may need to reach more than 10"  Hg when idling without a leaky manifold.

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I agree with Neil, if you have stops on the butterfly brackets slacken them off, if not just press each one with the engine running. I recently took SU's off a 6 and refitted an injection system and had the same issue. Just one inlet was responsible for increased tickover I could not believe how minute the movement was.

 

Rob

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  • 3 weeks later...
On 9/23/2019 at 11:04 PM, tr6tuga said:

Sticking trotle cable? Wrong routing? Ask me how i know

I had the same creeping idle, mine too was caused by a sticking throttle, however in my case it was due to the throttle pedal shaft being worn and it was catching, a replacement assembly fixed it.

 

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