Poor tick over (Hunting)

Technical Area Engine, Transmission, Exhaust etc
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  1. My model of MX-5 is: __2010 NC
  2. I’m based near: __Birmingham
  3. I’m looking for technical help or recommendations on: __poor tick over
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I am having issues with a poor tick over following removal and refilling of the main battery. Car was running fine and now starts ok from hot or cold, revs and pulls ok hot or cold. just when you pull up at a junction tick over almost stalls then rises and falls then settles at about 650 rpm and is ok until you pull up at the next junction. Anybody got any ideas?
Cheers DRD

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This is quite normal after removing the battery.

The ECU has to go through a relearning process to set its baselines for the various sensors and naturally this will mean that the idle will be erratic for a short while.

I’m guessing it’s never actually stalled and cut out?

To put it right, start the car from cold and let it idle for 10 or 15 minutes… That should resolve it, if it doesn’t take it for a run and gentle work it through the rev range… I.e gently and softly accelerate upto about 4k rpm…

After doing the above, and after a couple of days at the absolute most (depending on how much you drive it), it should sort itself out.

I changed my battery a while ago and had the same symptoms… The above procedure resolved the issue for me.

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Hi Chris,
Thanks for the info, so its an ECU relearning process. That one to remember.
Thanks again
DRD

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You may also have to reset the steering parameters after the battery disconnection. As you have already driven the car it may have done it it’s self. All you have todo is turn the steering from full lock to full lock. Best not done stationary because you will “tear” the tyres so either put an old mat or similar under each front tyre or do it as you slowly move the car.
Richard.

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There was an occasion on here where a mamber couldn’t for the life of him get it to relearn.

I’ve done this twice, the first time, it corrected it’s self on a nine mile commute.
The second time, it wouldn’t correct.
However, i left it in the garage on tickover for about 10-15 minutes by which time it perform the re-learn.

Considering you posted this yesterday, I’m guessing all will be OK today.

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Thanks to everyone for their responses, Still working from home at this point so not using the ca as much as usual, so I think the plan is this weekend to leave it ticking over for 20 mins then take for a spin in the sunshine with the roof down (which is compulsory if not raining :slight_smile: ) and see if the issue is sorted.
Thanks again all DRD

1 Like
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One last thing to throw into the mix, having done this several times, make sure the battery terminals/clamps are clean and tight fitting. Once had this issue and could not sort it. Cleaning and properly tightening the posts and clamps got it sorted after a short run of varying revs, gears and speed. Might just have been coincidental but it worked for me!

Barrie