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The dreaded N42

Posted: Fri Aug 24, 2012 8:52 pm
by DanThe
Anybody here brave/stupid/perverted enough? Ive got one in from a mate to 'have a look' at why its such a dog, missing like a bstard when cold runs ok when warm, keep getting the faults - misfire checksum failure - misfire cylinder one
No other faults, cyl 1 is firing fine, plugs/coils swapped etc, has the updated tensioner and the timing looks bang on :?

Re: The dreaded N42

Posted: Fri Aug 24, 2012 9:20 pm
by rich318i
and was it fine before the new tensioner?

Re: The dreaded N42

Posted: Fri Aug 24, 2012 9:28 pm
by rich318i
they got that valvetronic screw systerm shit on them dan?

Re: The dreaded N42

Posted: Fri Aug 24, 2012 10:43 pm
by DanThe
N42 = Valvetronic = shite, yeah :)

Re: The dreaded N42

Posted: Fri Aug 24, 2012 10:51 pm
by rich318i
yep that whats at fault needs a new one. £110 or that unit if i remember right. what software you use for reading faults?

Re: The dreaded N42

Posted: Sat Aug 25, 2012 10:05 am
by B7
Dan, if you want i can get barry to ring you if you PM me your number.

Re: The dreaded N42

Posted: Sat Aug 25, 2012 10:57 am
by DanThe
Spoke to Barry earlier Trev, needs a BMW Dealer spec puter to fix it, waved the turd off this morning :)

Re: The dreaded N42

Posted: Sat Aug 25, 2012 12:03 pm
by Dan320is
They're awful donks.

My ex had a 318ti with the 2.0 N42. It had valvetronic issues and then the chain tensioner failed. It doesn't have a removable front timing cover. In the end BMW paid for the parts as the car had only done 23k and we paid the labour, not bad for seven year old car.

Re: The dreaded N42

Posted: Sat Aug 25, 2012 12:10 pm
by appletree
My anti had one of these lumps had a slight knock oneday went to the garage to have it looked at turned out the oil had gone like jelly so the garage changed the oil and when they got it back next day it put the conrod though the block! Total wipe out cracked the head, pushed the plug out, dropped a valve one side and pushed the valve out the top of the head breaking both cam shafts.

Re: The dreaded N42

Posted: Sat Aug 25, 2012 1:00 pm
by DanThe
I did the right thing and told him to sell it quick :)

Re: The dreaded N42

Posted: Sat Aug 25, 2012 8:26 pm
by Andyboy
You need INPa or. GT11 to sort these. They're absolutely horrid things to work on.

Re: The dreaded N42

Posted: Sun Aug 26, 2012 12:43 am
by e30topless
a swan vesta and a gallon of esso's finest unleaded sorts the N42 out :D

complete shit, i did a head gasket on one it had me in tears :cry:

Re: The dreaded N42

Posted: Sun Aug 26, 2012 1:11 am
by badassyas
Basically the car needs hydraulic valve lifters... Adapting the valvetronic won't necessary help the cold running. The lifters are glazed and can no longer hold pressure.

Re: The dreaded N42

Posted: Sun Aug 26, 2012 10:28 am
by bss325i
SO many experts on this thread!

After instruction from me, Dan disconnected the eccentric shaft sensor and the engine ran much better.

This indicates wear in the mechanical valvetronic system as the way the valvetronic works is that it has .2mm of valve lift at idle. When the valvetronic system wears this valve lift decreases to nothing causing the valve to be shut at idle and cause rough running when cold and/or a misfire when the throttle is initially applied.

Disconnecting the eccentric shaft sensor with the engine running set the valvetronic to a default setting of max valve lift of 9mm at idle and uses the throttle butter fly to vary air intake.

To help cure the reduced valve lift at idle through from wear, there is a service function on BMW's diagnostics systems, BMW DIS/GT1 which is the old type or the current BMW ISTA.
This service function can increase the valve lift at idle to .6mm

Autologic may be able to do this but i have not had the chance to use it yet.

Re: The dreaded N42

Posted: Thu Aug 30, 2012 1:22 am
by fixedwheelnut
^^ Ditto^^ exactly what I was going to suggest when I saw the thread :)

Re: The dreaded N42

Posted: Thu Aug 30, 2012 1:25 am
by rich318i
bss325i wrote:SO many experts on this thread!

After instruction from me, Dan disconnected the eccentric shaft sensor and the engine ran much better.

This indicates wear in the mechanical valvetronic system as the way the valvetronic works is that it has .2mm of valve lift at idle. When the valvetronic system wears this valve lift decreases to nothing causing the valve to be shut at idle and cause rough running when cold and/or a misfire when the throttle is initially applied.

Disconnecting the eccentric shaft sensor with the engine running set the valvetronic to a default setting of max valve lift of 9mm at idle and uses the throttle butter fly to vary air intake.

To help cure the reduced valve lift at idle through from wear, there is a service function on BMW's diagnostics systems, BMW DIS/GT1 which is the old type or the current BMW ISTA.
This service function can increase the valve lift at idle to .6mm

Autologic may be able to do this but i have not had the chance to use it yet.


didnt i say this at the start of post??? by asking what software are you are using!!

Re: The dreaded N42

Posted: Thu Aug 30, 2012 7:41 am
by bss325i
rich318i wrote:didnt i say this at the start of post??? by asking what software are you are using!!
No. You said it would be the valve tronic motor. Which it isn't!

Re: The dreaded N42

Posted: Thu Aug 30, 2012 8:47 am
by pacerpete
Grrrrrrrrr ! :)

Re: The dreaded N42

Posted: Thu Aug 30, 2012 9:14 am
by bss325i
Do I have to use a smiley emoticon every time to show I'm not angry now? :)

Re: The dreaded N42

Posted: Thu Aug 30, 2012 8:40 pm
by Andyboy
He's been to Wokefield for the injections!

Re: The dreaded N42

Posted: Thu Aug 30, 2012 8:47 pm
by suchy
pacerpete wrote:Grrrrrrrrr ! :)
Haha :D

Re: The dreaded N42

Posted: Thu Aug 30, 2012 8:51 pm
by suchy
bss325i wrote:Do I have to use a smiley emoticon every time to show I'm not angry now? :)
"That's my secret Captain, I'm always angry" :)