e90 N51 P0016 cranks but won't start

SnowRacer · 10-08-2023, 12:51 PM

Quote:

Originally Posted by e91Owner

It’s ELE-131:

https://drive.google.com/open?id=1ph...H66noyRjj_vSGF

A little easier to see on ISTA, but it sounds like you don’t have that.

Tested the continuity from the sensor harness all the way back to the fuse block behind the glove box. No issues there.

e91Owner · 10-08-2023, 02:51 PM

If this were my car, I would assume that when the belt snapped, it broke a connection somewhere. If it’s not the position sensors and their connections, it would be the VANOS solenoids since you are getting both intake and exhaust faults.

https://www.tsbsearch.com/BMW/SI-B11-05-05

Have you done the 9V battery test on the solenoids themselves? I would also test the wiring on those if passes.

It sounds as if you have done all of the other items relating to 2A9A/B:

SnowRacer · 10-08-2023, 07:56 PM

Quote:

Originally Posted by e91Owner

If this were my car, I would assume that when the belt snapped, it broke a connection somewhere. If it’s not the position sensors and their connections, it would be the VANOS solenoids since you are getting both intake and exhaust faults.

Have you done the 9V battery test on the solenoids themselves? I would also test the wiring on those if passes.

Yes, used a 9V battery and watched them cycle, then sprayed them with brake cleaner to make them look new.

SnowRacer · 10-12-2023, 04:19 PM

The car qualifies for the SULEV warranty. Since all of these impacted sensors and the failed fuel pump should be covered by that, I had it towed to the dealer today and should have an update by next week after they do their diagnostics.

SnowRacer · 10-18-2023, 06:37 PM

Here's a quick recap and an update. 2010 N51 will crank but not start. Has cam synchronization errors. Serpentine belt broke, but all belt pieces are accounted for.

Dealer diagnosed the car and it has very low compression (30-60 psi) so very likely that something mechanical is broken that's letting the intake cam sit stationary while everything else goes around and around.

Taking a look at this video from a guy who had a similar no-start and no-compression issue, it looks like I could have the same issue (i.e. a broken bolt that attaches the cam sprocket to the cam).

I didn't take the valve cover off a few weeks back because the car was on the side of the road. Now the dealer wants $2337 to pull the valve cover and diagnose what's underneath.

The key issue here is that it has the SULEV warranty which I believe covers the VANOS system, but I'm not sure if it covers the bolt that attaches it to the camshaft. They don't seem to fully understand the intricacies of the warranty either but are investigating so we can collectively determine if it's worth the fee to look inside and whether they or I will ultimately be responsible for the fee and what lies beneath.

It'll either be a warranty success story or we will have a car to part out.

Any insights from the collective brain trust here with this new bit of info?

Thanks!

SlowE92 · 10-18-2023, 06:59 PM

Quote:

Originally Posted by SnowRacer

Here's a quick recap and an update. 2010 N51 will crank but not start. Has cam synchronization errors. Serpentine belt broke, but all belt pieces are accounted for.

Dealer diagnosed the car and it has very low compression (30-60 psi) so very likely that something mechanical is broken that's letting the intake cam sit stationary while everything else goes around and around.

Taking a look at this video from a guy who had a similar no-start and no-compression issue, it looks like I could have the same issue (i.e. a broken bolt that attaches the cam sprocket to the cam).

I didn't take the valve cover off a few weeks back because the car was on the side of the road. Now the dealer wants $2337 to pull the valve cover and diagnose what's underneath.

The key issue here is that it has the SULEV warranty which I believe covers the VANOS system, but I'm not sure if it covers the bolt that attaches it to the camshaft. They don't seem to fully understand the intricacies of the warranty either but are investigating so we can collectively determine if it's worth the fee to look inside and whether they or I will ultimately be responsible for the fee and what lies beneath.

It'll either be a warranty success story or we will have a car to part out.

Any insights from the collective brain trust here with this new bit of info?

Thanks!

And you cleaned/replaced the check valves for the vanos solenoids? Idk if id let someone charge me 2300 to remove the valve cover just to diagnose, you can do that yourself for free.99.

SlowE92 · 10-18-2023, 07:08 PM

Quote:

Originally Posted by SnowRacer

Here's a quick recap and an update. 2010 N51 will crank but not start. Has cam synchronization errors. Serpentine belt broke, but all belt pieces are accounted for.

Dealer diagnosed the car and it has very low compression (30-60 psi) so very likely that something mechanical is broken that's letting the intake cam sit stationary while everything else goes around and around.

Taking a look at this video from a guy who had a similar no-start and no-compression issue, it looks like I could have the same issue (i.e. a broken bolt that attaches the cam sprocket to the cam).

I didn't take the valve cover off a few weeks back because the car was on the side of the road. Now the dealer wants $2337 to pull the valve cover and diagnose what's underneath.

The key issue here is that it has the SULEV warranty which I believe covers the VANOS system, but I'm not sure if it covers the bolt that attaches it to the camshaft. They don't seem to fully understand the intricacies of the warranty either but are investigating so we can collectively determine if it's worth the fee to look inside and whether they or I will ultimately be responsible for the fee and what lies beneath.

It'll either be a warranty success story or we will have a car to part out.

Any insights from the collective brain trust here with this new bit of info?

Thanks!

Also remove the bolts and check them yourself, don't let the stealer charge you a mortgage payment just for a diagnosis.

SnowRacer · 10-18-2023, 07:34 PM

Quote:

Originally Posted by MakoB96

And you cleaned/replaced the check valves for the vanos solenoids? Idk if id let someone charge me 2300 to remove the valve cover just to diagnose, you can do that yourself for free.99.

Yes, did all the vanos solenoid checks and cleaning, swapped intake/exhaust and did the same with the cam sensors. With the low compression readings I think the culprit is something mechanical and not just solenoids and sensors.

Unfortunately at the time I didn't have my full suite of tools with me (son's car is in Georgia and I'm in Tennessee) so I made a calculated bet on what I knew at the moment that it was a fuel pump and sensor issue. Didn't have low compression on the BINGO card.

Yes, I can absolutely pack up the tools, make the drive and take the valve cover off myself. Don't think they'll let me do that at the dealership so would need to tow it to his house, take it off, then if it's a SULEV warranty issue have it towed back to them.

NZE90 · 10-18-2023, 08:27 PM

If it's 60 psi accross all cylinders I suspect the low compression could be caused by the repeated cranking of the engine and the resulting unburnt fuel in the cylinders.
The unburnt fuel loosens the carbon on top of the pistons causing it to flake off and get stuck under the valves which then causes low compression.

The "fix" for this is to add 10ml of engine oil into the cylinders through the spark plug holes, then crank the engine over via the starter with the spark plugs OUT for 5-10 seconds, this will distribute the oil under the valves and around the rings and any excess will get pushed out of the spark plug holes (be sure to cover the spark plug holes with a rag to prevent a mess)

The end result of all this is, the oil will bring the cylinder compression up (after refitting the spark plugs of course) long enough for the engine to be started, then all the carbon flakes will be burnt and blown out the exhaust. I am a retired mechanic and i have used this method quite a few times, especially on older BMWs (e36 e39) Rather than pay $2300 to a stealership, it would be worth trying this as it will only cost you a bit of time.

SnowRacer · 11-08-2023, 09:35 AM

That took a lot longer than anticipated. Car was eligible for the SULEV warranty, but the warranty system didn't accurately reflect its status, so had to deal with BMW NA for almost a month to get the records corrected.

The dealer found that the "timing was off" and replaced both intake and exhaust VANOS adjustment units along with the valve cover and the eccentric shaft sensor.

I inquired as to why the timing was off and they couldn't say. Not sure if the aluminum screws on the adjustment units broke or what. Still a mystery, but it has all new VANOS hardware and is now properly timed and all buttoned back up. It now runs great.

Total warranty cost was $4,400. Thankful for SULEV. No cost for me, except for a very long process to get everything handled.

Thank you to all who helped me troubleshoot this one. It really made a difference and I do appreciate the help. Hoping I can return the favor.

10-08-2023, 02:51 PM	#24
e91Owner e91Owner 426 Rep 1,131 Posts Drives: 2011 e91 & 2010 e60 Join Date: Mar 2018 Location: Out of the Office iTrader: (0)	If this were my car, I would assume that when the belt snapped, it broke a connection somewhere. If it’s not the position sensors and their connections, it would be the VANOS solenoids since you are getting both intake and exhaust faults. https://www.tsbsearch.com/BMW/SI-B11-05-05 Have you done the 9V battery test on the solenoids themselves? I would also test the wiring on those if passes. It sounds as if you have done all of the other items relating to 2A9A/B: Attached Images Last edited by e91Owner; 10-08-2023 at 03:19 PM..
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10-12-2023, 04:19 PM	#26
SnowRacer New Member 5 Rep 28 Posts Drives: e90 328i, e46 330i Join Date: Jul 2019 Location: Tennessee iTrader: (0)	The car qualifies for the SULEV warranty. Since all of these impacted sensors and the failed fuel pump should be covered by that, I had it towed to the dealer today and should have an update by next week after they do their diagnostics.
	Appreciate 0 Quote

10-18-2023, 06:37 PM	#27
SnowRacer New Member 5 Rep 28 Posts Drives: e90 328i, e46 330i Join Date: Jul 2019 Location: Tennessee iTrader: (0)	Here's a quick recap and an update. 2010 N51 will crank but not start. Has cam synchronization errors. Serpentine belt broke, but all belt pieces are accounted for. Dealer diagnosed the car and it has very low compression (30-60 psi) so very likely that something mechanical is broken that's letting the intake cam sit stationary while everything else goes around and around. Taking a look at this video from a guy who had a similar no-start and no-compression issue, it looks like I could have the same issue (i.e. a broken bolt that attaches the cam sprocket to the cam). I didn't take the valve cover off a few weeks back because the car was on the side of the road. Now the dealer wants $2337 to pull the valve cover and diagnose what's underneath. The key issue here is that it has the SULEV warranty which I believe covers the VANOS system, but I'm not sure if it covers the bolt that attaches it to the camshaft. They don't seem to fully understand the intricacies of the warranty either but are investigating so we can collectively determine if it's worth the fee to look inside and whether they or I will ultimately be responsible for the fee and what lies beneath. It'll either be a warranty success story or we will have a car to part out. Any insights from the collective brain trust here with this new bit of info? Thanks!
	Appreciate 1 SlowE92113.00 Quote

10-18-2023, 08:27 PM	#31
NZE90 Lieutenant 321 Rep 520 Posts Drives: 325i Join Date: Nov 2022 Location: Straya iTrader: (0)	If it's 60 psi accross all cylinders I suspect the low compression could be caused by the repeated cranking of the engine and the resulting unburnt fuel in the cylinders. The unburnt fuel loosens the carbon on top of the pistons causing it to flake off and get stuck under the valves which then causes low compression. The "fix" for this is to add 10ml of engine oil into the cylinders through the spark plug holes, then crank the engine over via the starter with the spark plugs OUT for 5-10 seconds, this will distribute the oil under the valves and around the rings and any excess will get pushed out of the spark plug holes (be sure to cover the spark plug holes with a rag to prevent a mess) The end result of all this is, the oil will bring the cylinder compression up (after refitting the spark plugs of course) long enough for the engine to be started, then all the carbon flakes will be burnt and blown out the exhaust. I am a retired mechanic and i have used this method quite a few times, especially on older BMWs (e36 e39) Rather than pay $2300 to a stealership, it would be worth trying this as it will only cost you a bit of time.
	Appreciate 0 Quote

11-08-2023, 09:35 AM	#32
SnowRacer New Member 5 Rep 28 Posts Drives: e90 328i, e46 330i Join Date: Jul 2019 Location: Tennessee iTrader: (0)	Finally an update That took a lot longer than anticipated. Car was eligible for the SULEV warranty, but the warranty system didn't accurately reflect its status, so had to deal with BMW NA for almost a month to get the records corrected. The dealer found that the "timing was off" and replaced both intake and exhaust VANOS adjustment units along with the valve cover and the eccentric shaft sensor. I inquired as to why the timing was off and they couldn't say. Not sure if the aluminum screws on the adjustment units broke or what. Still a mystery, but it has all new VANOS hardware and is now properly timed and all buttoned back up. It now runs great. Total warranty cost was $4,400. Thankful for SULEV. No cost for me, except for a very long process to get everything handled. Thank you to all who helped me troubleshoot this one. It really made a difference and I do appreciate the help. Hoping I can return the favor.
	Appreciate 0 Quote