e65 745i misfire/lumpy idle when starting from cold

[Elliot2000]

On dis- under the section where you can check daily codes of individual ecus, under dme there is a section called component activation in the second column - it may be under there. Otherwise you may have the create a test plan to activate it

[Patrick Bateman]

Cheers. Tried to run in INPA and DIS but get an error message from both when trying to activate the pump.

Here's a video of how noisy it is when starting from completely cold-

https://youtu.be/i_PAS6S6sbA

Stops at about 45 seconds. How bad does that sound to you?

[helix402]

I presume you have an N62? I’m not an expert on that engine. I have a feeling that the secondary air injection fault is a red herring and not the cause of the misfires. Diagnosis by Google suggests valvetronic levers, some one mentions an eccentric shaft tolerance test via diagnosis software.

Again this isn’t something I’ve done personally but if such a test exists it may be a useful diagnostic aid.

[Elliot2000]

helix402 said:

I presume you have an N62? I’m not an expert on that engine. I have a feeling that the secondary air injection fault is a red herring and not the cause of the misfires. Diagnosis by Google suggests valvetronic levers, some one mentions an eccentric shaft tolerance test via diagnosis software.

Again this isn’t something I’ve done personally but if such a test exists it may be a useful diagnostic aid.

I thought possibly valvetronic wear- but it’s occured on both banks within a week?

[Patrick Bateman]

I have googled this extensively and read about the intermediate levers on the valvetronic.

Surely unplugging the valvetronic actuators would be a quick test to determine if it's related? I have read about increasing the minimum lift on them as half a solution.

My main query at the minute is if it is related to an air leak of some sort, would it not be an issue all the time rather than what I'm seeing?

[Elliot2000]

To rule out the valvetronic- disconnect the valvetronic sensor (round plug connectors on rocker covers) on both banks and not the actuators, it should then stick them on max lift and if the fault is still there then u can safely rule it out. Also, if it was the valvetronic I’d expect it to be better when first started and then get worse when warmed up

does sound noisy , but hard to tell from that video

[Patrick Bateman]

It sounds like a jet engine but there's also that harsh, random sound that doesn't seem right to me.

That sounds an easy enough check, that's good if you think it would get worse as it warms up.

As an aside, I can't imagine working on these every day. I'm 6ft and my calves felt properly stretched while leaning over into the engine bay.

[Patrick Bateman]

I've unplugged the sensors so I'll see when I start the car tomorrow how it behaves.

The sound from the pump seems to have stopped altogether now on a cold start.

[Patrick Bateman]

4 out of 4 cold starts since unplugging the sensors and there have been no issues whatsoever.

Looks like i'll be adjusting the minimum valve lift in DIS.

Noisy air pump has definitely stopped being noisy at all too.

Edited by Patrick Bateman on Tuesday 13th February 20:28

[helix402]

Glad to hear you’re making progress fixing it.

[Patrick Bateman]

It seems the minimum lift was actually 0.1mm as the default value and not 0.3mm.

I'll need to see what it does to cold starts but I've set it to 0.8mm just now and it's certainly made the idle far smoother. Only really started to improve at about 0.5/0.6mm.

0.1mm- https://www.youtube.com/watch?v=5fu9dpLezCI

0.8mm- https://www.youtube.com/watch?v=OVMqZxmyoBA&fe...

For anyone looking to do this it's quick and easy in INPA.

After going into the engine DME it's just into 'activate' and then 'VVT'. There it will give you a bar readout in mm which you can adjust up or down and then hit 'prog' to save the setting.

[helix402]

Excellent feedback on the solution, thanks.

[Patrick Bateman]

Well we'll see how it fairs come the next cold start I suppose. Cheers for the help to you both.

[Patrick Bateman]

Started today and initially seemed ok then a misfire crept back in.

You know I think I'll say now that I regret buying this car, for a mainstream engine, the N62 is a fking disaster and not worth the hassle.

This is before getting to the likes of valve stem seals and the coolant pipe stting itself.

[iSore]

Try removing and cleaning all four Vanos solenoids. If they've not been out yet, they will have badly blocked gauze filters.

Yes, they are horrid things.

[Patrick Bateman]

iSore said:

Try removing and cleaning all four Vanos solenoids. If they've not been out yet, they will have badly blocked gauze filters.

Yes, they are horrid things.

How can they muck the design up so much after decades of making V8's.

[Patrick Bateman]

Back to the oil leak here. My usual mechanic has confirmed the upper right timing cover is causing it.

Premier Motors in Aberdeen reckon the job would be about £450 per bank to do the valve cover and upper timing cover gaskets.

The left hand side isn't leaking so could it make sense to only do the right hand side? As far as I can see, there's isn't a huge amount of repeat work if you were to do one side only then need to do the other at a later date.

My thinking is the car hasn't done 15k miles since the rocker cover gaskets were done (2.5 years ago), so I'm not worried about them as such. Also things like the spark plug tubes were replaced then, surely ok to re-use?

[Philv8s]

Does that include new rocker covers? It is BMW standard practice to replace the rocker covers at the same time as the gaskets as they can warp.

[Patrick Bateman]

No and that's news to me.

Any official BMW procedures I've seen for other jobs that require valve cover removal have never mentioned replacing the valve covers themselves,m nor have I seen it in any guides across multiple forums.

Edited by Patrick Bateman on Wednesday 21st February 20:22

[Philv8s]

I had mine done (under warranty) and queried why the covers were changed and was told it was their standard practice as to eliminate warped or damaged covers causing a failure in the new gasket.