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-   -   Starting problem in cold weather - N42 engine (http://www.bimmerfest.com/forums/showthread.php?t=598061)

neeeeo 02-01-2012 12:18 PM

Starting problem in cold weather - N42 engine
 
Hello,

my problem is a bit weird.

If it is outside too cold (under some -5 C) car won't run. I can start it without any problem, but motor die in 3 seconds. Then I can not start it anymore untill I leave it 30 min.
Once its started, its working well - no problem at all. Even if I leave it after ride up to 8 next hours, it will start well again.
But next day is the problem back.
I found, that after start - die the valetronic motor move excentric shaft to end position not aloving air to be sucked in to the engine. Starter just rotating motor freely with no compression.

The problem is gone in warm days. Reader didn't find any error messages.

I found some similar stories on the net, but none help me.:dunno:

Let me please know if someone know how to fix this problem.

RonaldRegan 02-05-2012 10:55 AM

I'm having the same problem...... No code either/check engine light. I took the battery to get checked. I was told I had a bad cell, replaced the battery and still no luck. Next I'm targeting the fuel filter. 138K miles original fuel filter..... after another expense just to throw a dart, hope this works.

SJBimmer 02-05-2012 11:27 AM

Quote:

Originally Posted by RonaldRegan (Post 6611626)
I'm having the same problem...... No code either/check engine light. I took the battery to get checked. I was told I had a bad cell, replaced the battery and still no luck. Next I'm targeting the fuel filter. 138K miles original fuel filter..... after another expense just to throw a dart, hope this works.

Changing the fuel filter should help. What I surmise is happening is that car starts initially because of fuel pressure after the fuel filter. Once the fuel is used up after the filter, and because a cold car requires a richer mixture, the engine is essentially starved for fuel. Waiting for a while lets the system re-pressurize, slower than it should because of the clogged filter. At 138K you have gone well beyond the useful life if the filter, and need a new one in any case. Hopefully the new filter will solve your problem, and please post back with results.

chansta 02-05-2012 11:46 AM

Quote:

I found, that after start - die the valetronic motor move excentric shaft to end position not aloving air to be sucked in to the engine.
if you have a code for the valvetronic motor the fuel system has nothing to do with your problem.

did you have your car serviced at a independent shop or by a independent mechanic recently?? most people dont realize that you need to relearn the valvetronic stopping points after carrying out any service where the valvetronic motor needs to be removed.

i am not sure what you're saying in tht quote.. is that the code you pulled from your vehicle??

neeeeo 02-16-2012 10:59 PM

Thanks all for reply.

yesterday I unpluged connector for excentric shaft sensor (for VVT) and car starts fine. But today the problem is back even with "disabled" VVT.
Now I maybe try replace the fuel filter?

Later:
I finaly get DIS to do learning procedure to VVT. So VVT is now learned, fuel adaptations reset. I will try tomorow morning cold start.

Final:
The car is now working fine (but it is not so cold outside), so the problem is fixed till next winter

chansta 02-23-2012 10:49 PM

Quote:

Originally Posted by neeeeo (Post 6637767)
Thanks all for reply.

yesterday I unpluged connector for excentric shaft sensor (for VVT) and car starts fine. But today the problem is back even with "disabled" VVT.
Now I maybe try replace the fuel filter?

Later:
I finaly get DIS to do learning procedure to VVT. So VVT is now learned, fuel adaptations reset. I will try tomorow morning cold start.

Final:
The car is now working fine (but it is not so cold outside), so the problem is fixed till next winter

thats good to hear :)

btw the learning procedure you carried out was for the valvetronic motor not the VVT (which is VANOS for BMW's). there are no relearning procedures in scanners for vanos.

neeeeo 12-10-2012 01:27 PM

Hi all,

my problem is back again as the temperature is under 0. During warm days I replaced:
Cam and crank shaft sensors, fuel filter, sparks, air filter...
Yesterday I also check fuel pressure and fuel flow and all is good.
The car just start and the die 2 sec after...
Any one solved similar problem?
:bawling:

JakuLuka 01-07-2013 02:04 PM

Hi!

I registered to this forum just because i have same problem and haven't found answer to it..
I have changed camshaft sensors, coils, sparks, fuel filter,CCV, MAF and solenoid valve o-rings.
Nothing seems to work. Please reply if you have solved this.
Thank you

(Edit: Actually i almost celebrated when i changed solenoid valve rings, car started fine and i were happy, but then it started to make terrible noise and i noticed i hadn't pushed valves all the way in. When i pushed them noise was gone but problem was back. (Sorry about my english.))

neeeeo 01-07-2013 02:13 PM

I dont have any good news. Its still about go, or wait till its not so cold outside.
I plan to do some more tests, so will inform you about results.

QAfred 01-07-2013 03:20 PM

1 Attachment(s)
I wonder if a faulty IAT Intake Air Temp sensor would cause this?
It functions to adapt or fine tune the fuel mixture and engine timing based on varying intake air temperatures ...#3 in photo.

real oem:

http://www.realoem.com/bmw/showparts...79&hg=11&fg=40

JakuLuka 01-07-2013 09:11 PM

I was thinking that too, but laptop shows it works....

JakuLuka 01-08-2013 08:50 AM

neeeeo how did it start doing this for you? i did buy this car few weeks ago in this condition and i would like to know if there were some other symptons. Have yours valvetronic motor been replaced? cause this one has and i was wondering if local dealer did something wrong...

neeeeo 01-09-2013 01:01 PM

No, it was not, but the excentric shaft was out for cleaning.
Everything set up right.

The Valvetronic system is not working, till temperature of motor rise up. Intake valves are fully opening (9,2mm, with valvetronic disabled).
When engine is cold, it is operated by buterfly valve (just after MAF). It is operating also from manifold pressure sensor.
I plan to measure injectors open time, when the error happen. Will post results.

EDIT:
Now I wondering, if it can be oil pressure. JakuLuka wrote it was OK, when the vanos selenoid did not worked. Mailbe as oil is thick, it will do something with vanos.
I try also disconnect the selenoids for vanos.
It must be some mechanical fault as once engine runs, it work without any problem (even during cold weather).
I definitely suspend fuel pressure, as it was measured. Electric should be also OK, as the engine start at begining properly. It must be something with air supply or fuel injecting or spark timing.

JakuLuka 01-11-2013 05:15 AM

Neeeo, Here's couple things i noticed when researching fault: My motor dies if i spray start spray in intake. So it seems bmw get too much fuel. And when i took "Butterfly" thingy off intake had some sh*t inside. I took my car to bmw specialist (not dealer) and he will take a look next week. I'll inform what he founds

neeeeo 01-12-2013 06:11 AM

Interesting, maibe I have look too.
Today I try to unplug vanos selenoids, but no change. I took me 30 minutes of cranking and waiting and cranking till the engine finaly started.
When I look on the stick for oil level I noticed it was completly covered with white oil/water mix. I think its time to oil change. Maibe it will help.
I also measured fuel injections and they looks OK. It must be an air or spark problem.

JakuLuka 01-20-2013 09:05 AM

I think i might found something. this is different car but my symptons are pretty much same.
http://www.e90post.com/forums/showthread.php?t=697252
my sensor had oil in it too... Now im waiting for new sensor and try it...
i did know it had oil in it but i though it is normal :D

neeeeo 01-20-2013 12:51 PM

My got also oin in it. Please let me know, if replacing fix the problem. This one is not cheap fix.
DIS show position of cam shaft on my engine (read from the sensor), so it will be very interesting if replacing will fix it.
Thanks.

JakuLuka 01-20-2013 01:05 PM

That sensor actually only tells to vvt what position valvetronics cam is. cam shaft sensors are different place.
Or so i have understunded

neeeeo 01-22-2013 09:43 AM

It is cam shaft, but not for valves, it is for rocker arms adjustment. You right. The sensor tells to VVT angle of this shaft.
There is a way, how to test it. If you unplug the connector from the sensor, the car will run from buterfly valve only. VVT will be automaticaly set to fully open and stay there. The car should be operating normaly, but it will loose few hp.

Any news about the starting problem?

JakuLuka 01-27-2013 02:28 PM

Im losing my mind.. have changed too many parts.. Did you drive limits to valvetronic after excentric shaft was out? and you didn't have any symptons before shaft were taken off?

neeeeo 01-28-2013 08:37 AM

Yes, I did the learning procedure (few times to be shure).
The starting problem occured only once before. The car didn't got problem even in -23C.
Hard to say, if it got any think to do with repairs.

Things check till now:

fuel pump
fuel pressure
fuel injectors
DME software
DME cold joints
VVT position sensor
2 cam shaft sensors
crak sensor
MAF sensor
2 temperature sensors
Manifold pressure sensor
Motor compression
Relays for injectors and DME

Things to be check:

Butterfly valve
Oil temperature sensor
VVT electronics
Vanos actuators??

Can't see what else it can be...
Why the hell the engine runs, when its not so cold?
Why it always start up on first try, but stall after 2 seconds (when it is too cold).
Why I can not start it any more (after stall) for 3 - 10 minutes and then it start again (most time only for a second and stall again)
And why it runs after it hard start even in cold weather?
And why it runs fine whole day (even with 9 hours break)?
Wired problem...

JakuLuka 01-28-2013 08:40 AM

I think it has something to do with them.. Earlier i said wrong. it wasn't motor that was replaced it was eccentric shaft. Did you replace intermediate levers too or just shaft? and it started right after that cleaning or little by little

JakuLuka 01-28-2013 09:39 AM

I did read something about intermediate lever, someguy had like 3mm detrition in his levers and his valves were left open in some situations..

actually i think he meant that they didn't open because i cant see where the detrition should be so they wouldn't close

neeeeo 01-28-2013 09:54 AM

No i did'nt change any levers or shafts. All I did was to remove excentric shaft, VVT motor, VANOS with cam shafts. I did good cleaning of all components and put it back together (offcourse as they were before removing, each part on exact same place)
I think, the problem just camed. Not litle by litle, but happend once and still persisting.
This is a challenge for me :p

JakuLuka 01-30-2013 12:13 PM

Did find something weird today. I started bmw and stalled it.. (Mine stalls from garage too if right after start put pedal to the medal. it rises rpm to 3000 and chokes after that. loses pressure too..) Took battery off and opened rocker cover. Timing wasn't right. It was about 12 o'clock and 10 o'clock. I started to spin motor from end of crack shaft and then heard loud noise from cams. I noticed that timing was fine again (2 o'clock and 10 o'clock.) Im just pissed i don't know wich cam moved :D. I called bmw expert friend and he said that there has to be something wrong with vanos coz timing should get back normal when engine isn't running.. I'm trying to find somewhere cam locking tools so i can open vanos units :D one thing i was thinking that i change cross solenoid valves if problem changes.. Hope you get some idea from this :DD

Oh yeah i had solenoid valves off the motor when i opened rocker cover so it should not be at them.... But still i want to try. :D


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