E46 325i Hard to start.

[Electron60]

Hi all.
I am new to this forum but I have been reading though it for quite a while in the hopes of it helping me to fix my 2003 E46 325i. Unfortunately it has not yet been able to help.
A little bit about me!
I am a mechanic of over 40 years experience on a lot of different vehicles including some very high performance equipment but I must confess that have only had this BMW for less than 1 year and it the first time I have had to work on a BMW at all.

The basic issue I am having is a prolonged "Cranking time" before the engine fires up. Once it fires up it runs flawlessly no matter how hard I choose to punish it.

This is what I have diagnosed as fact:
There is NO (ZERO, NANDA, NIL) spark at ALL 6 x spark plugs for at least 6 or more revolutions of the engine. After that the spark plugs come to life and all is well. It makes NO difference if the car is cold or hot or if you wait 2 seconds after it has been shut off or 1 hour. Every time you try to start it it still takes an excessive amount of cranking before the spark is "turned on???" and the car then bursts to life. Turning the key to START position for a while (in order to wait for fuel pressure etc) makes no difference.
There are NO battery or related starter motor issues. (I have all the necessary equipment at my shop to check this for sure)
There are NO fuel related issues either. All 6 x injectors are operating immediately (in turn) as the engine is cranked and the fuel pressure is also immediate when the key is turned on and is steady at 55 PSI (measured).
Crank angle sensor is new as are both the inlet and exhaust cam angle sensors. These were all changed out in an effort to find the cause behind this issue and replacing them didn't change the issue.
I have checked the fuses in the ECU compartment (in the engine bay) along with the Ignition harness connections and all of these are perfect.
There are NO vacuum leaks and all electrical connections have been thoroughly inspected in the engine bay.
There are NO earthing issues in the engine bay either and I even ran a new one "just in case".
I am really hoping that someone can PLEASE assist me with this issue.
This hard to start issue really spoils the experience of driving a great car like this.

[dworthy]

Welcome to the Forum!

So what code(s) are store in the DME/ECU? I am sure you may see one for the Crank position sensor, or perhaps one for a cam position sensor. One of those three can cause a long crank and there are other things too, but of course let's pull some data before just tossing parts at the car.

[Jelle]

I have this exact same issue when the crackshaft sensor is bad. I change this sensor about every 3 - 4 months and finally found one that has been working for more than 6 months now. I got some before that were DOA, so it might be good to check if the sensor you got is okay. The car always stores a fault on this sensor when this behaviour happens.

I have also tried the car simply not starting at all, and I have had it running pretty weird with almost no power, so there are various symptoms for this crackshaft sensor. Do you have a test kit for the car to read out errors?

If not I can recommend this kit:
https://www.ebay.com/itm/KFZ-Profi-D...gAAOSw~OxfKamG
Plus this cable kit:
https://www.ebay.com/itm/For-Delphi-...Cclp%3A2334524

I haven't found a car this kit can't connect to, but you do need a computer/laptop too.

[dworthy]

I have this exact same issue when the crackshaft sensor is bad. I change this sensor about every 3 - 4 months and finally found one that has been working for more than 6 months now. I got some before that were DOA, so it might be good to check if the sensor you got is okay. The car always stores a fault on this sensor when this behaviour happens.

I have also tried the car simply not starting at all, and I have had it running pretty weird with almost no power, so there are various symptoms for this crackshaft sensor. Do you have a test kit for the car to read out errors?

If not I can recommend this kit:
https://www.ebay.com/itm/KFZ-Profi-D...gAAOSw~OxfKamG
Plus this cable kit:
https://www.ebay.com/itm/For-Delphi-...Cclp%3A2334524

I haven't found a car this kit can't connect to, but you do need a computer/laptop too.

^^^ This is why you should stick with OEM on sensors, for this is a job you don't want to do every couple of months.

[shadowpuck]

anymore, on critical sensors, even OEM can be a problem. i use only OE now on those items......

[Mless5]

I had one injector keep dripping into the cylinder after the car was shutoff, causing exactly the same prolonged cranking symptom.

[Jelle]

^^^ This is why you should stick with OEM on sensors, for this is a job you don't want to do every couple of months.

I have tried OEM parts twice now and they did exactly the same. For the moment I have a delphi sensor and it has been holding up for some time now, I do always keep a replacement on hand though, driving around with it in the trunk ready to replace it if needed

[dworthy]

Bosch, Siemens, Hella are the OE provider to BMW for those sensors, and the only ones I will trust not to break in a year or so.

[Electron60]

Bosch, Siemens, Hella are the OE provider to BMW for those sensors, and the only ones I will trust not to break in a year or so.

Thanks for the feedback everyone.
I hear what you are all saying regarding the Crank angle sensor but please trust me on this........it is not the sensor! There is a TOTAL absence of spark from all plugs for the first 6+ revolutions and then it "magically appears" and all is then well. The car then performs flawlessly with heaps of power and torque along with great fuel economy. I drive it for hundreds of kilometers at a time and once it starts (after the long cranking delay) it does not miss a beat.
I have a bit more testing to do on it (electrically) and once I get time to do that I will post back the results (simply a lack of time right now).
Once again, many thanks to all those who have responded.
Cheers

[dworthy]

I would see about testing the cam position sensors as well, for the DME needs the correlation information to start the engine.

[jclausen]

Don't over the crank sensor it's just the same as the cam shaft sensor in design if either sensor is intermittemly failing the engine computer has no idea the position of the shaft

[Electron60]

Don't over the crank sensor it's just the same as the cam shaft sensor in design if either sensor is intermittemly failing the engine computer has no idea the position of the shaft

I understand what you are saying and I would normally agree with you however, it is statistically impossible for a crank angle sensor to only fail during the first 6+ revolutions of the engine while cranking the starter motor. It is my experience that a faulty sensor (albeit intermittently) would cause a hiccup or misfire or some other anomaly while it is running for hours at a time ( I often drive the car for hours at a time). Don't forget, I have already replaced this sensor and the two cam sensors with Zero change to the way it starts. NO power to all 6 coils when trying to start every time whether hot, cold etc is the real "root problem" .........................the "root cause" of the lack of power is the big mystery that I am trying to get to the bottom of. I am planning to add a small, temporary jumper cable from the starter solenoid (solenoid engagement wire not B+) to supply power to the coils via two power diodes to prevent any reverse current/voltage flow that would hold the starter motor engaged when the cars normal power to the ignition system kicks in. Time is my enemy here and I will get to this as soon as I get a chance. This will effectively bypass whatever is controlling the "normal" power supply to the coils while cranking, and then see how it starts.
Stay tuned and once again, thanks for the feedback.
Cheers

[MarcoZandrini]

When you try to start the engine does the the tachometer needle move?

[Electron60]

When you try to start the engine does the the tachometer needle move?

Yes it does but only reads about 100RPM or so.

[Electron60]

Thanks to all those who have responded to my questions here. The car is now completely fixed.
This is what was wrong. The camshafts were out of phase with each other. They were close.....damn close, but close was not good enough. I purchased a good top end timing kit and set about re-timing the camshafts and Vanos etc and now the car starts first go and has more torque and better responsiveness to boot.
Once again, thanks to all those that have offered suggestions here.
Cheers

[shadowpuck]

i'm glad its fixed - and thank you for letting us know.

how in the world did it get that way, though? any idea?

[Electron60]

i'm glad its fixed - and thank you for letting us know.

how in the world did it get that way, though? any idea?

I removed the head due to a blown head gasket. I was unaware at the time that you required a timing kit in order to reassemble it and so I simply reassembled the engine in accord with how I believed it should go back together (mechanically). (I have been a qualified mechanic all my life) As I said, close but not close enough as it turns out.
I wouldn't have thought that small cam timing phase errors would have killed the voltage supply to all the coil packs for 6-10 revolutions and run fine after that???

We all live and learn.
"None of us don't know what we don't know".
Cheers all.

[shadowpuck]

ahh, that would have been handy information to know originally.....

glad its fixed - enjoy the car!