Difficult cold start and 2A43 code

lowrydr310 · 08-14-2020, 08:27 PM

I bought a 330i last night and drove 350 miles home with no issue. This morning when first trying to start, it started right up then stalled immediately. It did this twice more and then the third time it kept cranking and wouldn't start. I tried again and pressed the accelerator to the floor and it started up and stumbled briefly but then idled perfectly. While warm I drove around and shut off and started up with no issues. So it's either a coincidence that this just happened or it's the reason the seller was getting rid of the car (the car is otherwise in excellent shape and I do all my own repairs so I'm not worried.)

I pulled codes with INPA and have a 2A43 code (P107A). Sounds like a valvetronic motor error, what should I check first? I can get a new motor easily enough at the salvage yard, though this car had the valve cover replaced just a few months ago so I'll have to check all the connections. From what I can tell this is likely the electric valvetronic motor itself and not the eccentric shaft sensor.

Is there any way to tell when the car is using the throttle body instead of the valvetronic motor?

FIXED! See post #9 below, it was a faulty eccentric shaft sensor. I've drive the car nearly 30K miles since then and no problems.

lowrydr310 · 08-15-2020, 01:12 AM

Now I can't get it to fire at all. It starts then stalls immediately.

I got another code now:
2A38 valvetronic, monitoring, sluggish movement

This is in addition to the 2A43 code. Both showed up only after these cold starting problems. Looks like a Valvetronic motor problem. Is there a way to test the motor operation before I go and get a new one? Is there a way to bypass valveteonic and force the car to use the throttle plate?

E92William · 08-15-2020, 02:44 AM

Maybe your motor is stuck in the fully closed valve position. What you could do is turn it counterclockwise a bit from the Allen key in the back of the motor and see if it starts. I assume if it can't control it it would automatically set to using the throttle. If you see it idles good and all moving it that one bit towards open, then you can probably crank it fully open and just use the throttle to drive around, provided this is even what's actually keeping you from starting.

lowrydr310 · 08-15-2020, 09:29 PM

Another update tonight. I left the car overnight in my garage then removed the Valvetronic motor and spun it by hand with a 4mm Allen key several revolutions in both directions. I reinstalled it and when turning the ignition on but not starting the car, I could hear the valvetronic motor initializing now. When I started the engine, it fired right up.

Initially was idling a bit rough (maybe too much fuel left in the cylinders from all the failed starting attempts last night?) but then smoothed out at the higher cold start idle RPM, however after about a minute the RPMs dropped to around 550 and it felt like it was going to stall. It didn't ever stall, but would stumble around 550. I restarted a few times and the car started immediately every time, but this low stumbling idle persists. Also after sitting for a while and trying to restart it wouldn't start, but after manually moving the valveteonic motor with the Allen key as if I was going to remove it (clockwise until resistance felt) then letting the motor reinitialize, the car would start again but still with the stumbling low idle.

No codes are set from it either. I cleared those 2A43 and 2A38 codes from yesterday and no new codes have been stored since then.

From my reading, these symptoms sound like a failing eccentric shaft sensor however I don't currently have and never had any eccentric shaft sensor codes. Is that still possible? I pulled the connector and it has a little bit of oil in it. This is sad because I have the service records indicating the valve cover gasket was just changed six months ago, it'd be a shame to have to do that all over again.

How can I test proper operation of the valvetronic motor and eccentric shaft sensor?

lowrydr310 · 08-16-2020, 08:27 PM

Another update

I installed a replacement valveteonic motor sourced from a junkyard and I have the exact same symptoms. This time in addition to the previous codes triggered again, I got the 2A37 code for the eccentric shaft sensor. Looks like I'll just have to try replacing that.

I also noticed that the valvetronic motor position is reported at 175.5 degrees during this rough running and doesn't change. I tried using INPA to verify it moves to the commanded position but it doesn't seem to be moving at all.

E92William · 08-16-2020, 09:52 PM

There's always the chance that the junkyard unit was junk. Try another one from a car that maybe got hit in the front so you know it was at least running when it ended up at the yard lol. Ofc replacing the ESS is a lot more involved than trying another motor.

Does your stock one you had on move in inpa?

lowrydr310 · 08-17-2020, 12:03 AM

Quote:

Originally Posted by E92William

There's always the chance that the junkyard unit was junk. Try another one from a car that maybe got hit in the front so you know it was at least running when it ended up at the yard lol. Ofc replacing the ESS is a lot more involved than trying another motor.

Does your stock one you had on move in inpa?

Nope. Neither the stock one or the junkyard one respond to any commands in INPA. I can hear them both initialize when I turn the ignition on. I also used ISTA to initialize with both motors and both seemed to initialize fine.

Also the problem. with my junkyard is that apparently lots of people want the exhaust manifolds with integrated catalytic converters so all of the 10 or so N52s including X3s and E60s had the subframe dropped with the engines hanging on the ground and the valveteonic motor pressed against the inner fender. I only found one that had enough space to remove the valveteonic motor.

The car starts fine and the valvtronic motor is working but then it's stick at 175.5 degrees. I'm guessing this is the failsafe and it's using the throttle plate? It starts and runs fine but then as soon as the idle drops after warming up it's low and is idling rough. I took it for a short drive around the block and the throttle response is crap. Just a few days before any of these symptoms the car was running perfectly.

I ordered the new eccentric shaft sensor and all gaskets. Fortunately this isn't my first time removing a magnesium N52 valve cover so I still remember all the tricks. It's not difficult just takes some time. I also just snagged a case of some Warsteiner Oktoberfest so one of those will help pass the time.

E92William · 08-17-2020, 03:53 AM

That's good that kind of will rule out anything by replacing the sensor. I believe the stop for the motor is somewhere around 170 or so degrees so most likely it's just at full valve lift and using the throttle plate to go.

lowrydr310 · 08-17-2020, 11:57 PM

I finished replacing the eccentric shaft sensor and a new valve cover gasket along with valvetronic motor gasket and eccentric shaft sensor gasket and all is seemingly good now! It started right up and behaved normally, no stalling or sputtering or long cranks, and after warming up the idle dropped normally.

I'm pretty sure that was it - the sensor I removed had a date stamp on it of 2005 (year my car was made) and the new one had 2019 on it. It was apparently the original eccentric shaft sensor with 134K miles. I'm just extremely happy that it happened after I got home and not in the middle of the long drive I recently took.

I didn't get a chance to drive it yet but I'm pretty sure that the eccentric shaft sensor was the problem.

E92William · 08-18-2020, 12:16 AM

Hopefully it's good next time you go to drive. Glad it's fixed

mecheng77 · 08-18-2020, 07:16 AM

I don't think the motor fails often it is usually the sensor. Did it have oil on the plug? Did you get the oem version?

lowrydr310 · 08-18-2020, 10:39 AM

Quote:

Originally Posted by mecheng77

I don't think the motor fails often it is usually the sensor. Did it have oil on the plug? Did you get the oem version?

The motor was apparently fine. When these symptoms started I removed the eccentric shaft connector and sure enough there was oil inside.

I bought the VDO/Continental version. The original sensor I removed from my car has the BMW logo and a BMW part number. The replacement sensor has all other identical markings except the BMW logo and part number are ground away, so I'm pretty certain they're the OEM supplier.

Blahy445 · 08-18-2020, 02:06 PM

I´ve got similar issue with my 325i N52, 2.5l. Car is starting normally but almost stall but only during cold start!!!. There was also oil in Eccentric shaft sensor plug, so i replaced it last week, but problem is still there. Any ideas? No codes

Maybe camshaft sensor? Here is video with similar symptoms, but mine is worse.

lowrydr310 · 08-18-2020, 03:24 PM

Quote:

Originally Posted by Blahy445

I´ve got similar issue with my 325i N52, 2.5l. Car is starting normally but almost stall but only during cold start!!!. There was also oil in Eccentric shaft sensor plug, so i replaced it last week, but problem is still there. Any ideas? No codes

Maybe camshaft sensor? Here is video with similar symptoms, but mine is worse.

Did you replace the eccentric shaft sensor with a BMW part, VDO, or some other brand? If another brand, that may be the problem. Though if it's just barely stalling it might be another issue - VANOS solenoids, MAF, or minor air leak.

I will say that when my eccentric shaft sensor problems started, the car would crank and not fire, or if it did start it would immediately shut off. Then when it did start and idle low, it was running horribly, with poor throttle response and bouncing revs.

I think before focusing on another eccentric shaft sensor, check out the VANOS solenoids or MAF sensor, and check for leaks in the crankcase ventilation system (cracked breather hose or cracked valve cover).

Blahy445 · 08-19-2020, 07:01 AM

Quote:

Originally Posted by lowrydr310

Did you replace the eccentric shaft sensor with a BMW part, VDO, or some other brand? If another brand, that may be the problem. Though if it's just barely stalling it might be another issue - VANOS solenoids, MAF, or minor air leak.

I will say that when my eccentric shaft sensor problems started, the car would crank and not fire, or if it did start it would immediately shut off. Then when it did start and idle low, it was running horribly, with poor throttle response and bouncing revs.

I think before focusing on another eccentric shaft sensor, check out the VANOS solenoids or MAF sensor, and check for leaks in the crankcase ventilation system (cracked breather hose or cracked valve cover).

It was VDO, i will try disconect MAF sensor and we will see...Vanos solenoids are cleaned, there was only one thing with them. When I was shake them in my hand, one of them was clicking more than the other one...So probably one of them is opening less.

Blahy445 · 08-20-2020, 03:15 AM

Ok, MAF sensor is ok. Im still thinking about Vanos...you know, symptoms are almost same like when Eccentric shaft sensor is bad, but it is brand new, i have also lost low end torque. it must be a little thing somewhere....

Blahy445 · 08-29-2020, 07:39 AM

Ok, cold start issue solved! The valvetronic re-calibration was needed and now its fine again! However, car is still not powerful as it was. I cleaned solenoids but i will try to replace them.

E92William · 08-29-2020, 10:47 AM

Thats great. Any codes left over?

Blahy445 · 09-16-2020, 12:02 PM

Well, problem is back....Now, there are no codes!!! The car has been running perfect but every morning when I start it the rpm drops to below 500 it stumbles for a bit and then it normalizes and everything is okay. When I start it for the rest of the day it starts just normal. The only problem is the cold start in the morning.

I´ve changed spark plugs today from BOSCH to NGK and nothing...Hoses checked...

I don't know what to do anymore...any ideas? Help please

E92William · 09-16-2020, 03:14 PM

You know what, I think this is more of vanos problem than anything. Have any of you two cleaned the check valves on the side of the engine for the vanos system even if there isn't a code? You'll most likely get one stored very soon if it's doing it again. I doubt it's valvetronic related at this point.

My car what it does is the exact opposite by revving up only upon cold start maybe once or twice and then it's fine. Checking live data I saw that the fuel trims were going positive I believe when it revved up then normalizing but I'd have to test it again to double check. Maybe your trims are going negative causing the idle drop. I'll be cleaning my own check valves this weekend to see. No codes aswell.
My consensus is check valves that are clogged or are not moving as they should would drain oil out of the vanos system when the engine is shut down means the engine has to fill up the entire system and can't control timing on cold starts causing all sorts of issues.

Blahy445 · 09-17-2020, 02:43 AM

It is super clean :/ both of them.

BMWPE7 · Today, 09:48 AM

Hello, I’m encountering a very similar issue to what’s described here. OP was this ever resolved?

I recently replaced my valve cover (and gasket) as well as my eccentric shaft sensor. I did this partially because I was experiencing a bit of a rough idle and I suspected I may be buying oil because of a failed PCV valve.

After this job I ran into this 2A43 code when cold starting my engine and I occasionally get a misfire on cylinder 4. I’ve ruled out the ignition coil and I have no reason to believe that the coil connector is the issue. My next thought it to try another valvtrinic motor I have available but if this fails maybe I’ll give spark plugs a go.

I should also note that I did reset the motor limits using a fix well code reader.

I’d appreciate any input I can get. Thanks!

08-14-2020, 08:27 PM	#1
lowrydr310 Robot 2016 Rep 2,396 Posts Drives: 2006 330i, 2007 E93 335i Join Date: Apr 2013 Location: Souhtrne Califniora iTrader: (0)	Difficult cold start and 2A43 code I bought a 330i last night and drove 350 miles home with no issue. This morning when first trying to start, it started right up then stalled immediately. It did this twice more and then the third time it kept cranking and wouldn't start. I tried again and pressed the accelerator to the floor and it started up and stumbled briefly but then idled perfectly. While warm I drove around and shut off and started up with no issues. So it's either a coincidence that this just happened or it's the reason the seller was getting rid of the car (the car is otherwise in excellent shape and I do all my own repairs so I'm not worried.) I pulled codes with INPA and have a 2A43 code (P107A). Sounds like a valvetronic motor error, what should I check first? I can get a new motor easily enough at the salvage yard, though this car had the valve cover replaced just a few months ago so I'll have to check all the connections. From what I can tell this is likely the electric valvetronic motor itself and not the eccentric shaft sensor. Is there any way to tell when the car is using the throttle body instead of the valvetronic motor? FIXED! See post #9 below, it was a faulty eccentric shaft sensor. I've drive the car nearly 30K miles since then and no problems. Last edited by lowrydr310; Today at 03:40 PM..
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08-15-2020, 01:12 AM	#2
lowrydr310 Robot 2016 Rep 2,396 Posts Drives: 2006 330i, 2007 E93 335i Join Date: Apr 2013 Location: Souhtrne Califniora iTrader: (0)	Now I can't get it to fire at all. It starts then stalls immediately. I got another code now: 2A38 valvetronic, monitoring, sluggish movement This is in addition to the 2A43 code. Both showed up only after these cold starting problems. Looks like a Valvetronic motor problem. Is there a way to test the motor operation before I go and get a new one? Is there a way to bypass valveteonic and force the car to use the throttle plate?
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08-15-2020, 02:44 AM	#3
E92William Banned 2007 Rep 2,025 Posts Drives: 2008 E92 328xi Join Date: Nov 2019 Location: Miami iTrader: (0) Garage List 2008 BMW 328xi [0.00]	Maybe your motor is stuck in the fully closed valve position. What you could do is turn it counterclockwise a bit from the Allen key in the back of the motor and see if it starts. I assume if it can't control it it would automatically set to using the throttle. If you see it idles good and all moving it that one bit towards open, then you can probably crank it fully open and just use the throttle to drive around, provided this is even what's actually keeping you from starting.
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08-15-2020, 09:29 PM	#4
lowrydr310 Robot 2016 Rep 2,396 Posts Drives: 2006 330i, 2007 E93 335i Join Date: Apr 2013 Location: Souhtrne Califniora iTrader: (0)	Another update tonight. I left the car overnight in my garage then removed the Valvetronic motor and spun it by hand with a 4mm Allen key several revolutions in both directions. I reinstalled it and when turning the ignition on but not starting the car, I could hear the valvetronic motor initializing now. When I started the engine, it fired right up. Initially was idling a bit rough (maybe too much fuel left in the cylinders from all the failed starting attempts last night?) but then smoothed out at the higher cold start idle RPM, however after about a minute the RPMs dropped to around 550 and it felt like it was going to stall. It didn't ever stall, but would stumble around 550. I restarted a few times and the car started immediately every time, but this low stumbling idle persists. Also after sitting for a while and trying to restart it wouldn't start, but after manually moving the valveteonic motor with the Allen key as if I was going to remove it (clockwise until resistance felt) then letting the motor reinitialize, the car would start again but still with the stumbling low idle. No codes are set from it either. I cleared those 2A43 and 2A38 codes from yesterday and no new codes have been stored since then. From my reading, these symptoms sound like a failing eccentric shaft sensor however I don't currently have and never had any eccentric shaft sensor codes. Is that still possible? I pulled the connector and it has a little bit of oil in it. This is sad because I have the service records indicating the valve cover gasket was just changed six months ago, it'd be a shame to have to do that all over again. How can I test proper operation of the valvetronic motor and eccentric shaft sensor? Last edited by lowrydr310; 08-15-2020 at 11:51 PM..
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08-16-2020, 08:27 PM	#5
lowrydr310 Robot 2016 Rep 2,396 Posts Drives: 2006 330i, 2007 E93 335i Join Date: Apr 2013 Location: Souhtrne Califniora iTrader: (0)	Another update I installed a replacement valveteonic motor sourced from a junkyard and I have the exact same symptoms. This time in addition to the previous codes triggered again, I got the 2A37 code for the eccentric shaft sensor. Looks like I'll just have to try replacing that. I also noticed that the valvetronic motor position is reported at 175.5 degrees during this rough running and doesn't change. I tried using INPA to verify it moves to the commanded position but it doesn't seem to be moving at all.
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08-16-2020, 09:52 PM	#6
E92William Banned 2007 Rep 2,025 Posts Drives: 2008 E92 328xi Join Date: Nov 2019 Location: Miami iTrader: (0) Garage List 2008 BMW 328xi [0.00]	There's always the chance that the junkyard unit was junk. Try another one from a car that maybe got hit in the front so you know it was at least running when it ended up at the yard lol. Ofc replacing the ESS is a lot more involved than trying another motor. Does your stock one you had on move in inpa?
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08-17-2020, 03:53 AM	#8
E92William Banned 2007 Rep 2,025 Posts Drives: 2008 E92 328xi Join Date: Nov 2019 Location: Miami iTrader: (0) Garage List 2008 BMW 328xi [0.00]	That's good that kind of will rule out anything by replacing the sensor. I believe the stop for the motor is somewhere around 170 or so degrees so most likely it's just at full valve lift and using the throttle plate to go.
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08-17-2020, 11:57 PM	#9
lowrydr310 Robot 2016 Rep 2,396 Posts Drives: 2006 330i, 2007 E93 335i Join Date: Apr 2013 Location: Souhtrne Califniora iTrader: (0)	I finished replacing the eccentric shaft sensor and a new valve cover gasket along with valvetronic motor gasket and eccentric shaft sensor gasket and all is seemingly good now! It started right up and behaved normally, no stalling or sputtering or long cranks, and after warming up the idle dropped normally. I'm pretty sure that was it - the sensor I removed had a date stamp on it of 2005 (year my car was made) and the new one had 2019 on it. It was apparently the original eccentric shaft sensor with 134K miles. I'm just extremely happy that it happened after I got home and not in the middle of the long drive I recently took. I didn't get a chance to drive it yet but I'm pretty sure that the eccentric shaft sensor was the problem.
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08-18-2020, 12:16 AM	#10
E92William Banned 2007 Rep 2,025 Posts Drives: 2008 E92 328xi Join Date: Nov 2019 Location: Miami iTrader: (0) Garage List 2008 BMW 328xi [0.00]	Hopefully it's good next time you go to drive. Glad it's fixed
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08-18-2020, 07:16 AM	#11
mecheng77 Colonel 1022 Rep 2,259 Posts Drives: 2007 328i / 2014 M235i Join Date: Nov 2017 Location: Ontario Canada iTrader: (0) Garage List [0.00] [0.00]	I don't think the motor fails often it is usually the sensor. Did it have oil on the plug? Did you get the oem version?
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08-18-2020, 02:06 PM	#13
Blahy445 New Member 0 Rep 7 Posts Drives: Bmw e90 325i N52B25A Join Date: Aug 2020 Location: Czech Republic iTrader: (0)	I´ve got similar issue with my 325i N52, 2.5l. Car is starting normally but almost stall but only during cold start!!!. There was also oil in Eccentric shaft sensor plug, so i replaced it last week, but problem is still there. Any ideas? No codes Maybe camshaft sensor? Here is video with similar symptoms, but mine is worse.
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08-20-2020, 03:15 AM	#16
Blahy445 New Member 0 Rep 7 Posts Drives: Bmw e90 325i N52B25A Join Date: Aug 2020 Location: Czech Republic iTrader: (0)	Ok, MAF sensor is ok. Im still thinking about Vanos...you know, symptoms are almost same like when Eccentric shaft sensor is bad, but it is brand new, i have also lost low end torque. it must be a little thing somewhere....
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08-29-2020, 07:39 AM	#17
Blahy445 New Member 0 Rep 7 Posts Drives: Bmw e90 325i N52B25A Join Date: Aug 2020 Location: Czech Republic iTrader: (0)	Ok, cold start issue solved! The valvetronic re-calibration was needed and now its fine again! However, car is still not powerful as it was. I cleaned solenoids but i will try to replace them.
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08-29-2020, 10:47 AM	#18
E92William Banned 2007 Rep 2,025 Posts Drives: 2008 E92 328xi Join Date: Nov 2019 Location: Miami iTrader: (0) Garage List 2008 BMW 328xi [0.00]	Thats great. Any codes left over?
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09-16-2020, 12:02 PM	#19
Blahy445 New Member 0 Rep 7 Posts Drives: Bmw e90 325i N52B25A Join Date: Aug 2020 Location: Czech Republic iTrader: (0)	Well, problem is back....Now, there are no codes!!! The car has been running perfect but every morning when I start it the rpm drops to below 500 it stumbles for a bit and then it normalizes and everything is okay. When I start it for the rest of the day it starts just normal. The only problem is the cold start in the morning. I´ve changed spark plugs today from BOSCH to NGK and nothing...Hoses checked... I don't know what to do anymore...any ideas? Help please
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09-16-2020, 03:14 PM	#20
E92William Banned 2007 Rep 2,025 Posts Drives: 2008 E92 328xi Join Date: Nov 2019 Location: Miami iTrader: (0) Garage List 2008 BMW 328xi [0.00]	You know what, I think this is more of vanos problem than anything. Have any of you two cleaned the check valves on the side of the engine for the vanos system even if there isn't a code? You'll most likely get one stored very soon if it's doing it again. I doubt it's valvetronic related at this point. My car what it does is the exact opposite by revving up only upon cold start maybe once or twice and then it's fine. Checking live data I saw that the fuel trims were going positive I believe when it revved up then normalizing but I'd have to test it again to double check. Maybe your trims are going negative causing the idle drop. I'll be cleaning my own check valves this weekend to see. No codes aswell. My consensus is check valves that are clogged or are not moving as they should would drain oil out of the vanos system when the engine is shut down means the engine has to fill up the entire system and can't control timing on cold starts causing all sorts of issues.
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09-17-2020, 02:43 AM	#21
Blahy445 New Member 0 Rep 7 Posts Drives: Bmw e90 325i N52B25A Join Date: Aug 2020 Location: Czech Republic iTrader: (0)	It is super clean :/ both of them.
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Today, 09:48 AM	#22
BMWPE7 Registered 0 Rep 2 Posts Drives: 2007 328xi Manual Join Date: Oct 2024 Location: MA iTrader: (0)	Hello, I’m encountering a very similar issue to what’s described here. OP was this ever resolved? I recently replaced my valve cover (and gasket) as well as my eccentric shaft sensor. I did this partially because I was experiencing a bit of a rough idle and I suspected I may be buying oil because of a failed PCV valve. After this job I ran into this 2A43 code when cold starting my engine and I occasionally get a misfire on cylinder 4. I’ve ruled out the ignition coil and I have no reason to believe that the coil connector is the issue. My next thought it to try another valvtrinic motor I have available but if this fails maybe I’ll give spark plugs a go. I should also note that I did reset the motor limits using a fix well code reader. I’d appreciate any input I can get. Thanks!
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