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Discussion Starter #1 (Edited)
N42 Valvetronic motor replacement cost

Hi,

I've been told the Vanos on my 2002 E46 318ci may need to be replaced. Now it was a worse case scenario from my mechanic and not a full diagnosis owing to an intermittant fault.

The MAF was also mentioned as a possible fault.

It was hooked up to an autologic system that picked up no fault codes, a full system scan was done and also it was test driven with the autologic setup in place.

Symptoms:

When starting in the morning it can chug and run rough until revved.

It can be very unresponsive and chug in 1st and second gear from a standing start.

It can have a non responsive accelerator in 1st, 2nd and 3rd.

Gear changes can be hard to do smoothly, again, due to the accelerator being slow to react at times.

Is a vanos replacement an expensive job if that is indeed the cause?
 

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so did U got any faults on ECU or U just guess ? and which part on this engine U call VANOS? bad spark plugs and worn chain will make engine work bad ,very bad ,and no faults could be found on ECU .most other failed el.parts - sensors,will be shown as faults
 

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Discussion Starter #4
is it rattly at all id change maf first if not
Occasionally when you start it there is a rattling noise for about 1 second.

The Maf is the first thing to be replaced. My mechanic was just saying more worse case scenario.

I've to drop it back and have the Maf unplugged. It was late Friday at half seven so he was really doing me a favour looking at it at all
 

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Discussion Starter #5
so did U got any faults on ECU or U just guess ? and which part on this engine U call VANOS? bad spark plugs and worn chain will make engine work bad ,very bad ,and no faults could be found on ECU .most other failed el.parts - sensors,will be shown as faults
No faults at all.

Plugs were changed 3k miles ago and worked fine after.

The vanos afaik takes the accelerator input and translates it into the correct mixture of air and fuel (probably a very simplified version of what it does)
 

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vanos unit adjusts camshafts to get better power on all rev range ,and of course lower emissions .valvetronic -with help of cam shaft adjusts valve opening gap,to adjust incoming air in to combustion chamber,not throttle body like it was on most engines before this system came into production .
 

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Discussion Starter #8 (Edited)
vanos unit adjusts camshafts to get better power on all rev range ,and of course lower emissions .valvetronic -with help of cam shaft adjusts valve opening gap,to adjust incoming air in to combustion chamber,not throttle body like it was on most engines before this system came into production .
In that case I've gotten the parts mixed up. I almost certain it was the valvetronic motor he mentioned. Apologies for the mix up.

@MAF: I haven't had a chance to disconnect the MAF as I've just been under pressure at work. My mechanic was going out of his way to check what he did as it was very late in the evening.

So, worst case scenario, is the valvetronic motor an expensive part to have replaced????????????

I forgot to mention earlier that there is a metallic knocking noise audible when the engine is warmed up and ticking over. Any connection? It's faint but can be heard. It's coming from the top left front corner area of the engine.
 

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if valvetronic motor would be gone and would not adjust camshaft properly ,would be fault in ECU .if U have ticking noise,its worn all valvetronic system on camshafts or noisy chain .two main things to fail and both can make noise.take of rocker cover and check timing chain,if its not loose ,its valvetronic system.its my sugestions
 

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Discussion Starter #10
if valvetronic motor would be gone and would not adjust camshaft properly ,would be fault in ECU .if U have ticking noise,its worn all valvetronic system on camshafts or noisy chain .two main things to fail and both can make noise.take of rocker cover and check timing chain,if its not loose ,its valvetronic system.its my sugestions
Afraid it will getting passed to my mechanic when I get the time as it got a bit worse during the week.

I was driving when I started to get a knocking noise from the engine. I depressed the clutch and revved it which cleared it. No warning lights or knocking since but very worried about it now.

Is a chain replacement or valvetronic system replacement expensive?
 

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had exactly the same problem with my car got it sorted yesterday by a bmw mech turns out the chain had jumped a couple of teeth
 

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had exactly the same problem with my car got it sorted yesterday by a bmw mech turns out the chain had jumped a couple of teeth
I know this is almost a year old now but when your chain jumped a few teeth did you ever have starting issues? I fear mine has gone out of timing as I have an intermittent starting problem, low power under 2500revs and can be quite jumpy under load.

I've got a gasket ready for opening it up but whilst it's open I want to really hit it on the head and sort it!

No codes either!
 

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so did U got any faults on ECU or U just guess ? and which part on this engine U call VANOS? bad spark plugs and worn chain will make engine work bad ,very bad ,and no faults could be found on ECU .most other failed el.parts - sensors,will be shown as faults
 
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