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Discussion Starter · #1 ·
My MiTo has developed, for want of a better phrase, lumpy tickover. Turn A/C on & it smooths out the tickover. Its the 135MA TCT. It had a gearbox firmware update back in January when it had its first service.
the update improved the gearbox in M mode as it stopped it going for 1st gear as soon as it could at slow speed but has a weird new feature in that at a slow speed & revs in 2nd it has a flatspot, that once it clears it revs like a silly bugger. That I can live with as I know why it does it.
but this tickover is bugging me. Wondering if its dodgy fuel, iffy fueling post ecu upgrade or battery issues.
mulling a few things over as dealer isn't exactly local to me, but have been great at telephone stuff.
 

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What rpm is it idling at? Is the lumpy tickover at first start up from cold or all the time? What rpm is it idling at when it does it?

Did the sparks get changed at service as a lumpy tickover could be a poor firing cylinder?
 

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Discussion Starter · #3 ·
Idle RPM at start up is around 800rpm once its gone off fast idle.
Seems to be fine for the first 10 to 20 mins then once i come to halt can feel it get "lumpy". Almost like its trying to stall, but being an Auto it wont.
Turn the A/C on & you can hear the pump engage & the idle becomes nice & smooth again. Weird!!
As far as i know the plugs were changed at the service. It also had the firmware upgrade to the gearbox ecu.
 

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I see well I doubt its the plugs if its fine at first start.

It could be a sensor getting confused while your stationary which is causing the engine to decrease the richness of the supply and then when it gets close to stalling the engine increases it again. With AC on theres an increased load on the engine which stops this happening as it needs a richer supply.
 

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Discussion Starter · #5 ·
Think I may have sorted it, will know for sure Saturday if I go into town.
filled car up last night with the usual Sainsbury Super UnLeaded. Last couple of tanks have been bog stock unleaded. I've only ever used Super unleaded in the MiTo, gives slightly better MPG.
It now idles nicely now.
 

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Have you always used the super?

It maybe that the engine has learned to expect a certain concentration of fuel based on the 98/99 octane stuff. This means that when its got 95 octane in it, when it comes to idle it appears to be under fueling just a bit hence the lumpiness.
 

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Discussion Starter · #7 ·
Have you always used the super?

It maybe that the engine has learned to expect a certain concentration of fuel based on the 98/99 octane stuff. This means that when its got 95 octane in it, when it comes to idle it appears to be under fueling just a bit hence the lumpiness.
just about. Think first couple of fill ups we unleaded but after that used the super.
that's what was going through mind as well. Guess an ecu reset would "unlearn" its want for super unleaded.
Will see how the next few days go.
 

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We have 2 135MA in the family, both have a slighty lumpy tickover one more than the other. If you switch the A/C on then the revs rise slightly and they smooth out. 1 car is 3 y/o the other 2 y/o, wouldn't worry about it
 

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Discussion Starter · #9 ·
This felt like the engine was going to stall, actually reminded me of my old 1000cc Twin on tickover :)
 

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Discussion Starter · #10 ·
Well, got my lumpy tickover problem sorted last week.
Was out with the kids a week ago, car started running rough/EML flashing. On the way home EML came on solid along with "Check Engine" on the centre display.
Rang the dealer who said not to drive it, call it Alfa Connect. Spoke to the nice lady who called out the recovery folks.
He arrived, plugged his OBDC(sp) in & the MiTo wouldnt talk to it at all.
So he rang the AA(who deal with the recovery/roadside) & they said no problem but cant move the till its booked in at dealer(Bauer Millett btw, nigh on 45miles from me).
Back to Alfa Connect then. Nice lady books the job into Bauer Millett for the monday, so thats that bit sorted.
Next i need a car, no problem she says. One car reserved at local Enterprise. A 1.2 Corsa SXi. Engine felt like it was powered by a hamster on a wheel, one that smoked 40 a day. Couldnt pull the skin of a rice pudding. Less said about the better :eek:

The problem with my MiTo turned out to be a faulty MultiAir unit!!
Duly replaced under warranty which was a relief.
So now i have a nicely running MiTo again.

Cant fault Alfa Connect or Bauer Millett. Both provided excellent service.
 
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