Rpm Up & down when starting

I recently encounter this problem of unstable idling when starting car.

The rpm will go up and down for a few times on cranking. It's especially agressive when the engine is cold. Though it seems softer when the engine is still hot.

Anyone knows what wrong:helpp!:
 
Re: Rpm Up & down when starting

Is your ride a valvetronic model?
 
Re: Rpm Up & down when starting

Valvetronic engine?
 
Re: Rpm Up & down when starting

Then do you know if it is a 320 or 323 or 325 or 330 or 335? I hope you do.
 
Re: Rpm Up & down when starting

My guess, if valvetronic engine, check for valtronic cam sensor.
 
Re: Rpm Up & down when starting

Get the ignition coil/cylinder replaced. All 4 pcs in total.

Problem should be resolved after replacement.
 
Re: Rpm Up & down when starting

dont waste your money on changing things,get someone who knows about these cars to do a diagnostics first and check for problems

when the rev counter needle goes up and down at engine idle this is know as 'hunting'

the most command problem for this is fuel mixture is too weak or too rich

things you can do your self
1,if you have a second aux air pump fitted this it should run when the car is started from cold,
it sits on the exhaust mainfold side at the front of the car and when started it lets air in to the exhaust mainfold so to drop the exhuast emissions
the revets around the work pump work there way loose and the sounds like a blow exhaust when the car is 1st started,so check for this,pop the bonnet and start the car from cold then listen,if it is noisy you can use pk screws to repalce the revets,the housing is made from plastic

2,check pipes ans gaskets to make sure they are not cracked or splits

3,check the oil filler cap is on correcty and the dip stick is pushed in to place

4,dip the dip stick then remove a smell the oil on the stick in some cases can be contaminated with a high amount of fuel,if you only do short jornerys or sit in traffic all day you can get high amounts of fuel in the oil which then can build up vapour which is sucked back into the intake mainfold

5,breather canistors these have a diaphragm which split and suck in air,spray some wd40 where the canistor is when the engine is running and see if the rev go up and stay constant

there is loads more but will need some daignostics to be used
hope it helps
 
Re: Rpm Up & down when starting

That is ridiculously too much to do. Worst than changing things...


Why I suggest this?
I had the same problem! Nothing beats advice from the victim.
Be there. Done that!... Just few days ago. Solved the problem permanently.
Ur car is e90 yr 06, mine is e90 oct05. This is typical Wear n tear, Equipment life-span issue.

Cylinder Cost is $60x4pcs = $240.
Labour charges = depends on the workshop u engaged.
 

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