2005 745Li Cranks but doesnt start issue

Ok i have a 2005 BMW 745Li and the problem started about a week ago. I did my research and read alot of common problems on this forum. My problem is slightly different. A week ago after the big snow storm the next morning the car cranked but did not fire up. It cranked until battery died. I recharged the battery (good battery) still no start. I saw that it could be the fuel pump or fuel pump relay but a couple days later when the weather got warmer the car started and ran great. About 4 days later (today) the weather got cold again and again it cranks but doesnt start. I ruled out fuel pump / starter because it ran a couple days later. I was thinking maybe fuel pump relay but cant seem to find it. And i did make sure there is gas in the tank (half tank) and the fuses seem to be good as well. Im stumped because the car didnt work then in warmer weather started running and stopped again in the colder weather. If you have any info or more things i can check please help. Thanks

The problem seems to be with the fuel system, as the car is cranking. How cold did it get down to? Are you using regular fuel or premium fuel? What gas station?

What I'm thinking could be the issues:
1. Fuel is freezing (or the ethanol in the fuel is causing excess moisture that freezes and blocks/restricts fuel flow)
2. A dirty/clogged fuel filter along with #1.
3. Bad fuel pump relay that may be sticking when it's cold (due to parts contraction of the cold weather)

The easiest thing to do would probably get the fuel pressure measured when it's cold again outside and you are having this issue. That would give you more insight into what is going on.

Originally Posted by csmeance

The problem seems to be with the fuel system, as the car is cranking. How cold did it get down to? Are you using regular fuel or premium fuel? What gas station?

What I'm thinking could be the issues:
1. Fuel is freezing (or the ethanol in the fuel is causing excess moisture that freezes and blocks/restricts fuel flow)
2. A dirty/clogged fuel filter along with #1.
3. Bad fuel pump relay that may be sticking when it's cold (due to parts contraction of the cold weather)

The easiest thing to do would probably get the fuel pressure measured when it's cold again outside and you are having this issue. That would give you more insight into what is going on.

It wasnt to terribly cold probably around 25-30 degrees. I use premium gas and i believe the gas station i filled up at was Shell. I have not considered the fuel pump filter yet..... where is the fuel pump relay located? i tried searching the internet but cant seem to find it. I will also try and research on where the fuel pump filter is to change that out as well as testing the fuel pressure and i will post my findings thanks. The oddest thing is that the problem comes and goes. Thats what really throws me off

This should help! Look around this website for more, if needed.


http://tis.spaghetticoder.org/s/view.pl?1/07/10/24

Originally Posted by Tron830

Ok i have a 2005 BMW 745Li and the problem started about a week ago. I did my research and read alot of common problems on this forum. My problem is slightly different. A week ago after the big snow storm the next morning the car cranked but did not fire up. It cranked until battery died. I recharged the battery (good battery) still no start. I saw that it could be the fuel pump or fuel pump relay but a couple days later when the weather got warmer the car started and ran great. About 4 days later (today) the weather got cold again and again it cranks but doesnt start. I ruled out fuel pump / starter because it ran a couple days later. I was thinking maybe fuel pump relay but cant seem to find it. And i did make sure there is gas in the tank (half tank) and the fuses seem to be good as well. Im stumped because the car didnt work then in warmer weather started running and stopped again in the colder weather. If you have any info or more things i can check please help. Thanks

Start with the 'fuel filter/ with pressure regulator' replacement. It is the cheapest and the easiest fix. You can buy the OEM BMW fuel filter ($110) or go to ebay and order the Mann or Mahle for around $40-$50. Mann or Mahle brand works just as good. If the filter doesnt solve your problem then go with the Fuel Pump. The reason why you wanna do the filter first is because, it will most likely fix the problem and even if it doesn't, its still a good thing to have it replaced every 30-40k miles anyway. Trust me, I had cranking issues a few weeks ago and the fuel filter was my problem.
Alternatively, you can get a diagnostic test from the 'stealership' for a good $140 but believe me they will most likely mis-diagnose the problem and you will end up replacing quite a bunch of stuff before you get to the actual culprit.

Ok so i am starting with the fuel pump relay as its only $10 part i purchased it already and will be putting it in tonight or tomorrow morning. If that does not work i will go with the fuel filter then fuel pump. im weary on the fuel pump as it did start up... and the fuel filter throws me off a bit also but at 70$ i might as well try it. ill keep posting until the problem is fixed and hopefully it helps others. If there are other suggestions or comments please share

Ok so after purchasing a new fuel pump relay and fuel filter i decided to start with the relay and when i tried to open the hood it wouldnt pop. Followed the Keif's DIY on how to open it with no luck. With my great luck i went to work on one problem and stumbled into another one

Originally Posted by Tron830

Ok so after purchasing a new fuel pump relay and fuel filter i decided to start with the relay and when i tried to open the hood it wouldnt pop. Followed the Keif's DIY on how to open it with no luck. With my great luck i went to work on one problem and stumbled into another one

Tron,
Did you ever get your fuel problem fixed? If you did, what fixed it?

I have not gotten the problem fixed yet. Due to work and the fact that the car is stuck in my driveway weather is an issue ( damn chicago weather). As an update i have replaced the fuel pump relay ( ill post pictures of where i found it) no fix. I also tested the fuel pressure and am reading 0 which leads me to believe its the fuel pump. I will be taking out the rear seat this weekend and testing the fuel pump and going from there. I will update with pictures and the solution to my problem as soon as i find it.

I had what sounds to be a similar problem once last summer. I went out to my car at lunch time, hit start, and the engine cranked but would not fire up. Took the key out back in still wouldn't start. Next I put the gas pedal to the floor (kind of pumped it as if I was stuck in an old 1970's carburated car). I thought I heard something click. The car then started fine and have not had this happen since. I think what I did is the reset of adaptive transmission sequence, by accident as I didn't know about this at the time.

Even thought I have not had this happen more than once, I still wonder in the back of my mind "I didn't really do anything, hope I don't get stranded somewhere."

P.S. I also change the power module under the hood about 4 months later (can't remember the proper name..... PVM ?) due to issue I was having with a no crank no start. I don't think these 2 different issues are linked though.

ok so i put got to the fuel pump and attached to a battery and i can hear fuel pump making noise.. I have replaced the battery, checked all fuses, replaced fuel pump relay and yet still not starting. Car still does not have fuel pressure in the lines for some odd reason. i read something about a B pillar satellite? dont know where it is or how to test it though. Any more suggestions? When i put direct power to the fuel pump i can hear noise but when i put the key in and push start i do not hear anything....

I attached a battery to the fuel pump directly and then tried starting the car and it started no problem. but when i disconnect it obviously turns off. for some reason i am not getting power / ground to the fuel pump

bump? any ideas?

anyone have any useful information? keif?

Sounds like it could be a blown fuse, bad module or bad wiring. Fuel pump is controlled by the satillite B pillar module. Check the 15 amp fuse F73, it powers the module. Pump is connected to terminals 2 and 3 of module.

Originally Posted by Ggreg

Sounds like it could be a blown fuse, bad module or bad wiring. Fuel pump is controlled by the satillite B pillar module. Check the 15 amp fuse F73, it powers the module. Pump is connected to terminals 2 and 3 of module.

is that fuse located in the glove box? because i have tested every fuse i can find glove box and trunk and they are all good. how do i go about testing the B pillar module? i am trying to find a diagram for the power wiring for the fuel pump but am unable to find one that i can actually read. I will be trying to get to and test the b pillar module next i guess

Fuse is in the trunk on right side above battery............

Ive had something like that happen to me but in revers starst in good weather wont in hot weather or somethime in coold weather neether was told starter but if it was starter it would just stop workingthen told bad battery or key battery not charging right, I know that the computer for the key is under the cavin filter on the right side im gessing the fan where all the computers in there does not work well and when ever my car wont start i just open the hood the remove the filter then tap, bang on that box where all does computers are and car starts right up. yes it could be some thing just loose in there. hope this info helps.

Ok so i finally got the problem diagnosed and fixed. The issue was the B - pillar airbag module. Power runs through there and gives power to the fuel pump. I hope this help anyone else that encounters the same problem.

Cool