525i 2002 Crank but No Start

I have a 2002 525i that will not start at times, it's been progressively getting worse. When it happens, the car will crank strong but not start. The strange thing is that when it starts, I can drive the car all day. On weekends, I zip around town handling errands, etc. Once it starts in the morning, it will start every time during the day. During the week, it also starts every time after completing my 8hr work shift.

This only seems to happen in the morning, the car will not start after sitting over night. Sometimes when it doesn't start, I need to wait about a week before I get it to start. Sometimes only after a few days and a few times did not start in the morning but was able to start it in the evening on the same day. The times when the car starts, it starts up rather quickly and strong on the first crank.

The car has 83k miles on it and is garaged most of the time, since this is my 2nd car. I put about 4k miles per year on average. I purchased the car used with 68k miles back in 2009 and was fine up until about 4 months ago when this intermittent problem surfaced. As mentioned, it's been gradually getting worse. Worse meaning, I need to wait longer before the car starts again. Even then, when it starts, I'm able to go all day without any issues starting throughout the day.

I'm no mechanic but willing to do my research to narrow down the possible causes. Once I have a good idea of the problem, I will then shop for a mechanic to replace specific parts. Too expensive for my budget to have them diagnose, I've been took before and decided to take different approach this time around. If simple enough, I can even attempt to replace the part myself, that it, once determining what's involved and deciding if I can do myself. I've heard similar issues with 95 model being either the Fuel Pump/Filter, Fuel Pump Relay or Crank shaft Position Sensor. Not sure if this would be a similar case for my 2002 model. Any helpful leads on identifying the cause of this problem would be greatly appreciated! -Martin

I will start with the battery's, test them and check your connections, then next your starter, then the alt. Also check your fuses.

Originally Posted by jbonly21

I will start with the battery's, test them and check your connections, then next your starter, then the alt. Also check your fuses.

If it cranks strong it's not the battery, alt, or starter.
I doubt it is the fuel filter, it could be the fuel pump, relay, crank sensor or many other things.
To really find out what's wrong you need to see what's missing when it won't start.
Air, fuel, and spark are what's needed. One of them must be missing.

Given your symptoms, it suggests the loss of fuel line pressure is the reason. Once your car starts, it continues to start easily through the day. However, whenever it sits, the next start is often difficult and sometimes impossible. This suggests that the fuel line pressure is bleeding off when you car is sitting for an extended period of time. I would look at the fuel pump first and then forward.

Before you start guessing find out whats missing. Are you losing spark , or fuel ? You need to see if you have fuel presure when this is happening and check to see if it has spark then go from there.




http://www.eaceuroparts.com/

a strong crank but no start is usually a crank sensor.

Thank you very much for your responses and suggestions, I will troubeshoot further and post the solution when fixed. Thanks again for the help!

Originally Posted by MUribe

Thank you very much for your responses and suggestions, I will troubeshoot further and post the solution when fixed. Thanks again for the help!

if you do the crank sensor keep in mind you have to measure and get the gap correct. Check on TIS for this http://tis.spaghetticoder.org/

Will check this out, thanks for the tip!

Had the same thing happen once--it turned out to be my Key of all things--the car was sometimes recognizing the key and sometimes it wouldn't--I tried my other key and that fixed the problem. If you only have one key, you might try and reprogram it and see if it helps

Originally Posted by poolman

Had the same thing happen once--it turned out to be my Key of all things--the car was sometimes recognizing the key and sometimes it wouldn't--I tried my other key and that fixed the problem. If you only have one key, you might try and reprogram it and see if it helps

I did try the spare key but got the same thing, I was hoping it was the issue but no luck, thanks.

To assist in your diagnosis, I suggest you read these linked articles.

http://www.autohausaz.com/html/fuelpumps.html
http://www.aa1car.com/library/2003/us60324.htm

Ensure that you have spark and air, first (which you probably do since you can easily start the car when warm). Given that your car starts easily soon after previous use but has problems after sitting awhile, I believe that your fuel injection system is having trouble maintaining residual fuel pressure, long after shutdown. The Bosch fuel injection system requires 40 psi or more. Loss of pressure will create hard starting problems. Since the M54 has the integrated pressure regulator on the fuel filter, I would look there first as the cause (it is also easier and cheaper to replace than a fuel pump and is considered normal maintenance).

As a test, at your next cold start, try letting the fuel pump pressurize the fuel injection system first. Turn the key until you can hear the fuel pump start up. Leave it in this condition for a minute or so. Then attempt to start it. If it fires up, the check valve within the fuel filter is probably failing and causing residual fuel pressure to bleed off. Replacing the fuel filter should alleviate this issue.

Please report back on the resolution to your problem as this can be very helpful to others with similar issues.

Originally Posted by poolman

Had the same thing happen once--it turned out to be my Key of all things--the car was sometimes recognizing the key and sometimes it wouldn't--I tried my other key and that fixed the problem. If you only have one key, you might try and reprogram it and see if it helps

Poolman, please confirm you have had a strong CRANK no start caused by key issues.
Key problems usually prevent the car from cranking.


Sent from my ADR6350 using Bimmer App

Originally Posted by Fudman

To assist in your diagnosis, I suggest you read these linked articles.

http://www.autohausaz.com/html/fuelpumps.html
http://www.aa1car.com/library/2003/us60324.htm

Ensure that you have spark and air, first (which you probably do since you can easily start the car when warm). Given that your car starts easily soon after previous use but has problems after sitting awhile, I believe that your fuel injection system is having trouble maintaining residual fuel pressure, long after shutdown. The Bosch fuel injection system requires 40 psi or more. Loss of pressure will create hard starting problems. Since the M54 has the integrated pressure regulator on the fuel filter, I would look there first as the cause (it is also easier and cheaper to replace than a fuel pump and is considered normal maintenance).

As a test, at your next cold start, try letting the fuel pump pressurize the fuel injection system first. Turn the key until you can hear the fuel pump start up. Leave it in this condition for a minute or so. Then attempt to start it. If it fires up, the check valve within the fuel filter is probably failing and causing residual fuel pressure to bleed off. Replacing the fuel filter should alleviate this issue.

Please report back on the resolution to your problem as this can be very helpful to others with similar issues.

Thanks for the helpful advice, I will definitely report back with the fix as soon as I identify and confirm the problem, thanks again!

Acoste--You know--it's been so many years ago--I do think that I would turn the key and nothing at all would happen--my bad Roseanna Danna-my bad

I just changed the fuel filter this past weekend and all seemed fine all day but did not start the following morning. So we can now rule out the fuel filter as being the culprit. I'll be taking a closer look at the fuel pump next. I'll do some research first to see if I can perform some preliminary tests on checking the fuel pump before replacing. I know this will be a more expensive item to replace so I'll try to obtain something convincing before changing. Since this is my second car, I have some time to research a bit and troubleshoot the issue. I'll post additional updates as I work through finding the fix. Any additional comments or suggestions will be greatly appreciated.

I just changed the Fuel Pump Relay and the car started without hesitation. Typically, with this problem, when the car did not start it wouldn't start no matter how many cranks. I would need to wait a few days or over a week at times before it would start again. This time around, after trying a few unsuccessful attempts at starting, I changed the Fuel Pump Relay and the car started immediately! So far it's going on 3 days and the car starts consistently, I will know for sure after a few weeks. So far, it seems like this was the problem, but will wait some time before I confirm. I'll post back within a few weeks with final results.

Thank you for the update!

Originally Posted by Fudman

To assist in your diagnosis, I suggest you read these linked articles.

http://www.autohausaz.com/html/fuelpumps.html
http://www.aa1car.com/library/2003/us60324.htm

Ensure that you have spark and air, first (which you probably do since you can easily start the car when warm). Given that your car starts easily soon after previous use but has problems after sitting awhile, I believe that your fuel injection system is having trouble maintaining residual fuel pressure, long after shutdown. The Bosch fuel injection system requires 40 psi or more. Loss of pressure will create hard starting problems. Since the M54 has the integrated pressure regulator on the fuel filter, I would look there first as the cause (it is also easier and cheaper to replace than a fuel pump and is considered normal maintenance).

As a test, at your next cold start, try letting the fuel pump pressurize the fuel injection system first. Turn the key until you can hear the fuel pump start up. Leave it in this condition for a minute or so. Then attempt to start it. If it fires up, the check valve within the fuel filter is probably failing and causing residual fuel pressure to bleed off. Replacing the fuel filter should alleviate this issue.

Please report back on the resolution to your problem as this can be very helpful to others with similar issues.

THIS is happening to my car so every morning or after long park, I need to turn the key carefully to get and stay at the second ignite posisition

I spoke too soon, it happened again, the car did not start. I'm noticing on initial cranks, it feels like it wants to start but drowns out, as if it's not receiving sufficient fuel. After several tries, it simply cranked but did not start. That night, after unable to start the car, the alarm suddenly goes off during the middle of the night. On this rare occasion, I had parked the car outside and locked/armed before going to bed, I typically park inside the garage and don't lock or arm the car. The alarm ran through it's cycle three times before I woke and put the key in the driver door to unlock the car, that's what made it stop. This also happened once before, the car was parked outside at a friends house and the alarm went off. It ran a few cycles before it stopped on its own. I thought possibly a rumbling truck may have triggered it. Also, now that I think about it, there was one instance when both the driver and passenger windows automatically wend down about half way, the sun roof also retracted about half way as well. The car was parked in my garage and I remembered all windows and sun roof were closed. When I returned to the car several hours later, I found it with both front windows and sun roof half way open. I typically don't lock or arm the car when parked in my garage, I also leave all windows and sunroof completely closed whenever I park. This happened only once before during the beginning stages of the "no start" issue. It seems like all these symptoms are related as none of this ever happened before. It now appears that I have an electrical issue at play. Any thoughts or ideas on what component could be responsible for this? Any additional help would be greatly appreciated!

have you tried to check and clean ignition connection contacts?