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Idle keeps changind


New Member
Nov 27, 2015
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Idle keeps changing

Hi All
Just purchased new Sahara 200 (diesel), driven 500 km.
Idle speed keeps changing, will idle at 500 for about 15 seconds, then increase to 750 for about 10 seconds, then drops back to 500 and follows the same cycle indefinitely.
Does not matter if engine hot or cold.
Very annoying as at 750 rpm, vibration felt through break pedal.
Is this normal? Or is this an issue for dealer?
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I have no idea if its even possible but i wonder if your ecu is sensing the throttle cable needs adjusting and is compensating to keep the engine running ?
No cable, will be a pot (potentiometer) on the accelerator pedal, I could be wrong but the 200 series engine is effectively fly by wire like nearly all modern vehicles with ecu engine management, just one more reason to keep my 80 running as long as possible.
It could be a sensor issue so might be worth seeing if diagnostics throws up anything.
I don't know if the 200 has a regen cycle for the cat?
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Have you got the air-con on? My 80 does this with the air con on ;)
+1 on the AC, that's what it sounds like to me.
Hi All
Does not matter if the AC is on or not - still does it
But interestingly - if I put the car in PARK, it does not do it - as soon as it is put in drive with foot on brake its starts to happen again.
What is strange is that it is not random, after doing it today and timing the changes, the pattern is as follows:
500 rpm - 6 seconds
750 rpm - 11 seconds
500 rpm - 6 seconds
750 rpm - 11 seconds
500 rpm - 6 seconds
750 rpm - 11 seconds

And it cycles through indefinitely - tested it for a full 5 minutes and it followed the pattern for the full period - then put the AC on, and it did it for the following test period of 5 minutes.

As soon as put car into Park, it stops doing it with a resting rpm of approximately 550
Should have said above that when idling the alternator voltage (according to dash instrument value) is just below 14 volt - not sure if this is of importance
Yep, back to the dealer. Good luck with it. Sounds like an ECU thing if it is that accurate on timing.
My 150 did the same when the fridge was turned on. Might it be that? I don't recall the drop being that pronounced but you could see the needle dip