N12 vanos woes

7568 Views 31 Replies 4 Participants Last post by mike1967, Nov 13, 2021

Cody4130

Discussion Starter · Oct 19, 2020

2

I have been trying to get my 2009 cooper project to run properly for a couple weeks. Upon first start the idle is lumpy but eventually smooths out. The vanos position and eccentric shaft position move around with revs and load as they should. Actual and commanded values are within 1 degree. The eccentric shaft value is around 23-24 at idle. (All these values are in degrees) I can hear a faint thunk sound then the value changes to a static 121 commanded 119 actual for the cam timing (both cams) and 176 commanded 171 actual for the eccentric values. Again these values never change, idle, WOT no change. Once this happens the car idles smoother but feels "flat" it revs slowly after 4000ish rpm. Feels like it's missing 20-25% of it's power. I have two scan tools both show similar findings. I get codes for the szl signal, DME tank vapor vent, 278D vanos. Vanos solenoids are new and I've tried switching them.

After significant research and forum lurking I am confident my timing process was right. As described by mike1967. I used a Mini specific locking tool, feeler gauges to take up any slack, and holding the camshafts in place with a wrench while doing the bolt stretch. New everything was used, cylinder head, gaskets, bolts, pistons, bearings, chain, tensioner and crank gears ect. Ect. I followed the torque processes. Once finished engine was rotated by hand 4 times and rechecked. Then ran down the road brought back and rechecked again.
I am unsure if a strange secondary problem is related in some way, my cooling fans will not turn on once the car reaches over 200F or even 220F. The fan itself works if I provide a direct 12v power or unplug the temp sensor. It's like the DME won't send the signal.

Included a current photo.

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JTownPBX

· #2 · Oct 20, 2020

Your timing process meaning you timed the car yourself. A thunk sound!!!!!!!!
Did you machine the head? What is your head gasket thickness?

Cody4130

Discussion Starter · #3 · Oct 20, 2020

Head is new, head gasket was a standard thickness mahle one. A thunk isn't exactly the sound but it's the only way I can describe it. It sounds like something "switches off". Then the values go static and the idle smooths.
What would cause the values to be static?

Cody4130

Discussion Starter · #4 · Oct 20, 2020

Yes, I timed it myself following the instructions of mike1967.

Is there anyone who knows what the values "should" be and what would cause them to go static and not change. I'm trying to figure out if the root cause is a problem with the vanos gears? Or the eccentric shaft system?

Compression test was done when I checked the timing. 180 across all cylinders.

mike1967

· #5 · Oct 20, 2020

if vvt steppa motor ie screwed in to rear of head has a issue the ecu will detect it and will force a protection mode where the vvt and vanos will go in to a sort of limp mode,, also on the right side ie looking in engine bay you will see the sensor that reads the position of the vvt cam these can go faulty,, also as part of that sensor there is a coil that is screwed to the cam with allen bolt so poss to replace these go wonky sometimes ,
also the camshaft vanos oil control rings do wear old these are within the first cam journals ie one on exhaust camshaft and one on inlet camshaft,, its poss to replace these rings they are like small piston rings as such they control the oil to vanos for valve timing,,

Cody4130

Discussion Starter · #6 · Oct 20, 2020

This is the only photo I have of this area (taken during assembly). But Mike are you talking about the eccentric shaft sensor located in this area? I re used the sensor and coil from my old head. Perhaps it was damaged somehow?

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Cody4130

Discussion Starter · #7 · Oct 20, 2020

Vanos rings might be possible but the head is "new" (remanufactured from a reputable company) I have put less than 20 test miles on it since assembly.

mike1967

· #8 · Oct 20, 2020

was the head all built up by them ie all the spring fingers on rear of eccentric cam followers to inlet camshaft,, or did you reuse the cams from the old head, yes on the end of eccentric camshaft for vvt there is a 3 10mm bolts that hold it to end as such, on the eccentric shaft there is a coil mounted to it vie a single allen bolt,
why did the head get changed

Cody4130

Discussion Starter · #9 · Oct 20, 2020

The head was fully built by them. It was completely assembled with cams, followers eccentric shaft ect. minus the stepper motor and sensors.

I bought the car as a non runner previous owner said head gasket had blown due to the lower rad hose leaking and the car overheating. One of the combustion chambers was damaged so I bought a new head. Here are photos of the engine as I bought it.

Cody4130

Discussion Starter · #10 · Oct 20, 2020

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mike1967

· #11 · Oct 21, 2020

i got a citreon with same engine at mo been a project in spare time,, this had been cooked so badly and has same faulty as yours everything now rebuilt first start runs fine then gets to running temps and just switches and rattle from cam area,, when i get time to work it out i will post results on here for people,, think my next test is oil pressure gauge on it from cold see if pressure drops at point of noise,, if does then non return valve or oil pump maybe,

Cody4130

Discussion Starter · #12 · Oct 21, 2020

Is there some way to test the eccentric shaft sensor? Some specific voltages or resistance I should be looking for? I might buy the adaptor to test oil pressure. I'm wondering if the DME could be faulty causing this issue. It's so strange the values move as they should and then go static. I'll try to get a photo of the values before and after they go crazy.

mike1967

· #13 · Oct 21, 2020

think the bmw software insta d would have such info maybe but how to find it i dont know as rarely use it, it is possible the dme has been toasted,, i suspect the citreon i got is that due to over heated 02 sensor were cooked and spiked the ecu on 5v rail maybe,, ie the 02 sensors generate eletrical charge ie 600c 0,2v to 0.9volt when get really cooked they poke more at the ecu and can hurt them,

Cody4130

Discussion Starter · #14 · Oct 21, 2020

2

Here is what my scan tool shows. Do these look normal?
Idle was lumpy for a couple of minutes and then smoothed out. Photos were taken once idle smoothed out. Car rev'd well and was quiet.

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Cody4130

Discussion Starter · #15 · Oct 21, 2020

I took out the eccentric shaft sensor and refitted it. That seemed to solve my issue with the values not changing. Took it around the block and power delivery was surging, car had several misfires. Values all seemed good none went static. My cooling fan began working again as well.

I'm going to try a plug change and see if that fixes the misfires along with an oil change. Car has around 25 miles on it. And over an hour of run time after the full rebuild.

mike1967

· #16 · Oct 22, 2020

i have no reference points with that diagnostics tool as never use one like it, diagnostics i tend to use has actual and prescribed values showing, yours does show the vanos positions 59 and 60 degrees if thats on idle my autocom shows 35 and 36 on a 2008 mini one after a rebuild and everything was right on that car think that scan was 8 months ago and car still driving around well.
you may find the cat and 02 sensors are damaged from the engine failure ie oil or coolant etc,

Cody4130

Discussion Starter · #17 · Oct 22, 2020

I would assume the values would be the same regardless of which scan tool is used. I have an Autel with the mini specific software and this BMW/Mini specific Autophix model. My Autel is cellphone based and wouldn't do the steering angle or vanos adaptations the Autophix does. I'll take the car for a longer drive tomorrow now that the cooling fan is working and see if I encounter any more hiccups. I will post O2 values to see if they look ok. I believe one lambda was around .97-.98 and the other was 1.02-1.04. those seemed close enough to 1.0 that I wasn't concerned but I'm not ruling out a damaged cat or O2.

mike1967

· #18 · Oct 22, 2020

very common for cat and 02 sensors to be damaged or polluted with oil residue from oil burning,, there a trick in the trade but its a naughty one in the wrong hands i guess,, that said i always do this before doing engine refresh as dont matter if cook the rings or stem seats etc as all are getting replaced anyway,,, i start car get to running temps,, i then pull the coil pack wire clip off number 1 gearbox end and rev car until cat gets red in colour then put the lead on again keep reving until cat stops going red and then repeat this a few times,, this will turn the cat in to a furnace as the 1 cylinder with no spark will just add petrol fumes to cat and 02 sensors ,,,WARNING do this to long and will hurt it big time, but short controlled bursts i have brought a few back to life after,
also all of them after a rebuild take a good 5 cold to hot to cold runs to settle down from past dealings with these things,, not all scanners are equal,,, the 3k snap on diagnostics i use at work is really good and gives a side figure to all live data runs that can be trusted,, also with the support package snap on do and links to other garages who in put data about faults cured and found to help other users with a data base is really good,, but a 3k to buy it plus a year sub fee on top,, hence why i say for £50 autocom is about the cheapest good level scan tool for the money that offers a good live data options and also allows to work with all ecu's and will code most things etc,

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Cody4130

Discussion Starter · #19 · Oct 22, 2020 (Edited)

Started it today. Was randomly misfiring on all cylinders. I took out plugs and they were wet. Cleaned them with carb cleaner and dried them with a rag. Checked gaps all were 30 thousandths. (Bosch iridium OE plugs supposedly pre gapped). Put the plugs back in and switched the coil packs around in case one was causing issues.
Took it up the road and the car was surging badly and misfiring. No other codes but misfires. I checked the fuel trims and long term was -7.8 so it seems the car is running rich. Smooth running values were all over the place. Vanos timing switching but sometimes the commanded and actual values were 20-30 degrees off.

mike1967

· #20 · Oct 25, 2020

Vanos timing switching but sometimes the commanded and actual values were 20-30 degrees off. this would make me do a oil pressure test first off, then if i had 30 psi hot on idle increase to around 40psi mini at 3k perfect should be 80psi using a gunsun oil pressure gauge ie what i have in my tool box .. if good pressure then possible oil control solonoids or vanos sprocket while changing these would deffo replace the oil control rings in first camshaft journal main dealer part when these wear out the system will loose pressure to vanos sprockets and cause vanos to free wheel and cause all kinds of issues including rich running,, another issue i have found for running rich is under the inlet manifold the fuel tank vent valve can fail and dump tank fumes in to inlet manifold and cause rich running, but going on what you have found on live data i would say its a vanos issue

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