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AlanO
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Erratic tickover

270 R (2020 build). Help please. All's fine and dandy until its run for an hour or so and then the tickover starts to play up. Normally it's at just over 1000rpm but after a longish run it climbs to 2000rpm. Flicking the throttle takes it back down but invariably it climbs again. It occasionally cuts out completely when stationary and on other occassions it 'hunts' (pulsing between 1000 to 1300rpm) when stationary) It runs at steady 80°. Any clues please. Thanks.

Mrb00ns
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The standard mapping is a dog, in my experience. Get it remapped and it will run like a treat. 

timb2117
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Just a hought, double check the throttle cable is well lubricated and moves freely and the throttle butterfly same and the stop that it returns to has not been moved or gone out of setting.

- Very long shot as I dont think it would cause all those symptoms but you never know and its free to check, good luck.

Tim

SM25T
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Could also be the tiniest air leak on the inlet side.... Look for a split in an air hose around the inlet manifold.

AlanO
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Helpful thanks. I wondered about remapping as have checked throttle action. Will investigate for air leak and see how it goes on F&C run.

Dixa1225
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Check the TPS setting.  You will need Easimap & the cable to check.

AlanO
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Thanks. You've set me off reading past blatchat posts and learning TPS settings! https://www.caterham7diaries.com most helpful!!

MTW
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I had hunting and irratic idle when warm and it turned out to be the O2 sensor, after it was replaced the car runs great (as great as the standard map allows) again.

2020 420R Mint green 

AlanO
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Just by way of an update, mainly in case others have similar troubles...

The car got worse on the way to Aberdovey, hunting or fluctuating tickover, cutting out every time the car stopped etc. Well last nights bedtime reading of past Blatchats and a couple of useful blogs suggested first trying the 'throttle reset'. (Ign on, 5 slow full depressions of the accelerator, ign off. Then start). We'll I'm pleased to say that it did the trick and we drove home without incident and the car resting and a nice gentle idle at lights etc. Many thanks! 

Jonathan Kay
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Well done.

Thanks for adding the solution.

Jonathan

StevehS3
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Great that it is sorted but can a Sigma (with MBE ECU) have the throttle position set using that process? It looks very much like the way a K with standard Rover ECU is done.