Car Spluttering From Idle + Momentary Oil Level Light - S50 VANOS

[M3AN 4016]

UPDATE 21/01

I've "fixed" the problem, it was a faulty VANOS exhaust solenoid. After three days of intermittent problems the car failed to start. I replaced the VANOS and re-timed the engine and it seems to be okay at the moment. Details throughout this thread.

ORIGINAL POST

Okay so I jumped in my car yesterday after stopping in at the hardware store and went to pull out onto the main road and *cough* *splutter* a few times just from idle to around 1200 RPM. The car didn't seem like it was going to stall, a little bit more go pedal and it was fine. The car was already up to operating temperature.

It did it once more on the way home from idle (pulling away from traffic lights). But it doesn't do it every time.

On the way to the office this morning it happened again. Also, if I coast down a hill put it in neutral and let the revs drop to idle and tap the gas I can occasionally make it splutter - I did this twice and both times the oil level light came on momentarily and immediately extinguished. Oil level is fine (could probably do with another 500mls but it's good).

The oil light does not come on every time the cough, splutter happens.

Full power and no symptoms above about 1200 RPM.

E36 M3 3.2 6 Speed.

Almost seems like fuel but I can't correlate to the oil light...

Any ideas, this is a bit of a concern.

Cheers.

Edited May 14, 2016 by M3AN

[BMTHUG 1057]

check and clean your air flow meter, if not that does it feel like a misfire? It could be one of the coils breaking down under load also. Could also be a bad spark plug but I have the feeling it may be a dirty air flow meter, wouldn't hurt to clean the throttle body as well. Common problems related to the symptoms you are describing. May even be a fuel pump issue but highly unlikely. Oil light is definitely something else

[M3AN 4016]

Thanks SJ.

It doesn't feel violent or consistent enough to be a misfire... I think (because I've not experienced one in this car before).

I'll give the MAF a clean when I get home... I tested the coils 12 months ago and they were fine... might have to do that again and check the plugs.

[BMTHUG 1057]

I think it may just be a dirty MAF, or even the connector can sometimes build up a little dust or dirt where the loom plug meets the maf. Use some contact cleaner to clean the contacts, but more often than not it's a build up of dirt on the MAF element. You are welcome man

[hybrid 1043]

Pop over .. will connect up the live data on it we can log whats happening then go through it.

PM me

[M3AN 4016]

Pop over .. will connect up the live data on it we can log whats happening then go through it.

PM me

Thanks, will do.

[M3AN 4016]

Pop over .. will connect up the live data on it we can log whats happening then go through it.

PM me

Mailbox is full I think... send me a PM...

Edited January 21, 2015 by M3AN

[M3AN 4016]

Okay so cleaning the MAF sensor did nothing, the problem is worse today.

Absolutely no problem above ~1500 RPM.

Oil level light still comes on occasionally when it happens!

Might have to pull the coils tonight.

Edited January 21, 2015 by M3AN

[BMTHUG 1057]

Ahhh sh*t man. It could even be fuel pump issue. If it feels like its starved of fuel then its likely it may be a fuel pump. Inspect your fuel filter too bud

[M3AN 4016]

Okay - mistake on my part - it is the oil level light that comes on, not the pressure light, that never comes on.

But the level light flickers now when the spluttering occurs and sometimes stays on for a few seconds. The ignition on self test does not throw up a level warning. I'm about to check it again and top it up but I'm sure the oil level is fine.

Problem is definitely getting worse.

Edited May 14, 2016 by M3AN

[aja540i 1906]

Oil level sensors fail pretty commonly, the m62 one is in the bottom of the sump, i assume yours will be down there too, triangle shape alloy thing with 3 bolts and a plug. Drain the oil first!!

[M3AN 4016]

Seriously I love to hate this car... or is that hate to love it?

• A3 (163) MSS50 Control Module Fault - Internal
• 16 (022) VANOS Exhaust Valve - Over Advanced

My VANOS exhaust solenoid has failed for one reason or another.

The failure of the vanos solenoid will cause the DME to not utilize the vanos. Unfortunately the engine timing is left in the same position as when the failure occurred. Thus the engine will likely behave better at low RPM and worse at high RPM, or worse at low RPM and better at high RPM. Engine misfire with fault codes can also occur.

- Beisan Systems

Hopefully it's just a dry solder...

[M3AN 4016]

For anyone that cares the car tried but failed to start this morning when I went to verify the codes.

Looks like the VANOS is coming back off.

[M3AN 4016]

Who knew you could borrow a S50 double VANOS unit?

Hoping to get this in tomorrow if it proves necessary after some more investigation.

Cheers Mark.

Edited May 13, 2018 by M3AN

[M3AN 4016]

Here we go again...

Edited May 13, 2018 by M3AN

[M3AN 4016]

Those with keen eyes that know VANOS might spot the difference... the "depth" of the splined shaft in the red circle should be similar (ish) to the one in the green rectangle. It should protrude some.

Also when we took the cap off the exhaust cylinder cover on the VANOS it blew out pressurised oil which indicates that the exhaust solenoids had failed closed (or open, I'm not sure actually).

I think I'll need to remove the exhaust cam tomorrow to get to that shaft but it is what it is, then I'll re-time and chuck the new VANOS on.

Edited May 13, 2018 by M3AN

[BreakMyWindow 1874]

Plenty of evidence the oil services have been religiously done. Very clean in there.

[M3AN 4016]

Yeah, I've owned it for most of its life (>2/3) and have been pretty meticulous with as much as I can.

However I pulled my plugs today as a part of this procedure and they all had shocking gaps and need to be replaced immediately. I learned I need to check them more frequently and also check my last Inspection 1 receipt.

[handgrenade 189]

Dave do you want to rebuild my vanos at the same time? Seems like you've done it enough times to be able to do it blindfolded!

[M3AN 4016]

After today buddy I don't want to see the inside another VANOS unit ever!

[M3AN 4016]

Another full day... cam out, engine re-timed, new VANOS installed. I don't recommend this to relax.

But - apparent success - it started up perfectly first time and sounds pretty sweet to be honest. I've only taken it for a short test drive at less than 4k RPM but it all seems good.

No trouble codes and cam timing is only about 0.4-0.6 degrees out from "perfect" according to the live data (which I've not looked at through the entire rev range yet). That's a pretty sweet result really.

Let's see how it holds up to the next few hundred kilometers yet...

[M3AN 4016]

3 years on and no trouble.

Thread images fixed.