[SnapCoupe]

I have been trying to figure out my long crank issues ever since I purchased my car around a year ago. The symptoms are as follows: Whenever the car sits for more than 6 hours around 50% of the time upon the first press of the start button, the car will continue to crank but refuses to start. If I press the button again to stop it and once more to try to start it again, it will fire up immediately. When it is colder than about 50 degrees F outside, this will happen just about every time the car sits for longer than 6 hours.

Without blindly replacing components, I have been trying to diagnose the issue to get to the bottom of it. I have ran multiple fuel system pressure tests on BMW's diag equipment, but all of them come back normal. I have logged plenty of runs with multiple styles of driving on MHD and my rail pressure is exactly where it should be. Unfortunately my car (2011) does not have a low pressure fuel sensor, so there is no way to tell if the LPFP is feeding the HPFP as intended. My best guess as of right now is that the LPFP is slowly dying out and upon initial priming of the HPFP, the LPFP does not have enough pressure to push the fuel to the HPFP. Hence why the second attempt to start always works.

In regards to these cars, the HPFP is always the one to go first. It's the weak link and replacing it seems to fix most fueling problems that people tend to have. Though, I am curious to hear if anyone has replaced a LPFP on a 2011 without the LP sensor. If so, why did you replace it? How did you know that the LPFP was the culprit? And, had you already replaced your HPFP prior?

Thanks guys!

[9krpmrx8]

Do you smell any gas? I had a long crank issue after the car sat for a few days (fuel line depressurized) and found that my fuel pressure regulator on the drivers side was leaking. I was sure that it was related to my stage 2 LPFP install. Funny thing is, I smelled gas at times and my GF told me I was crazy, lol. I guess the insulation does a good job of hiding the smell and the fuel evaporated quickly in this heat. Or it just got worse over time.

[SnapCoupe]

Originally Posted by 9krpmrx8

Do you smell any gas? I had a long crank issue after the car sat for a few days (fuel line depressurized) and found that my fuel pressure regulator on the drivers side was leaking. I was sure that it was related to my stage 2 LPFP install. Funny thing is, I smelled gas at times and my GF told me I was crazy, lol. I guess the insulation does a good job of hiding the smell and the fuel evaporated quickly in this heat. Or it just got worse over time.

I haven't smelt any more gas than what I would consider normal with a catless DP. How did you come to the conclusion about the regulator? Did the car ever throw any codes?

[9krpmrx8]

Same, I am catless and have driven a catless turbo rotary for the last 14 years so I am just used to it.

No codes, the car ran fine and if I drove it daily it wasn't an issue it was just after two days the line completely empty so the lag in starting was due to the pump priming the system.

[SnapCoupe]

Originally Posted by 9krpmrx8

Same, I am catless and have driven a catless turbo rotary for the last 14 years so I am just used to it.

No codes, the car ran fine and if I drove it daily it wasn't an issue it was just after two days the line completely empty so the lag in starting was due to the pump priming the system.

This is exactly what I am thinking is happening on my car. Was there anyway to know before you decided to pull the back seat out? Or were you just taking your best guess and hoping that was cause of the issue?

[Soden82]

When I bought my 2011 e92 N55 last May it had the same issue you were describing. Long cranks almost everyday in the summer time and it got me worried that the LPFP was going out. About a month into ownership I threw a jb4 on and the long cranks virtually went away except for the occasional long start in the winter under very cold temperatures. I'm going to upgrade the lpfp anyways eventually but am curious as to whether I should replace any other components when I do my lpfp

[9krpmrx8]

Originally Posted by SnapCoupe

This is exactly what I am thinking is happening on my car. Was there anyway to know before you decided to pull the back seat out? Or were you just taking your best guess and hoping that was cause of the issue?

I had a similar issue on another car that I caught right away thanks to having a fuel pressure gauge so I when straight to removing the seat and cover.

[SnapCoupe]

Originally Posted by 9krpmrx8

I had a similar issue on another car that I caught right away thanks to having a fuel pressure gauge so I when straight to removing the seat and cover.

How hard was it to get in to the tank/pump? I might try checking it out this weekend if I have the time and it isn't too involved to pull the rear seat out.

[MTK24]

I have a 2011 and mine is still good.

They last pretty long assuming you don't run more than e30 in the tank

If yours is bad and want to change it then upgrade to fuel it stage 2 LPFP

[SnapCoupe]

Originally Posted by Vampire335i

I have a 2011 and mine is still good.

They last pretty long assuming you don't run more than e30 in the tank

If yours is bad and want to change it then upgrade to fuel it stage 2 LPFP

I don't have access to ethanol, so that isn't a worry for me. Would it even be beneficial to upgrade the LPFP if I am just using pump 92?

[9krpmrx8]

Originally Posted by SnapCoupe

How hard was it to get in to the tank/pump? I might try checking it out this weekend if I have the time and it isn't too involved to pull the rear seat out.

Stupid easy, just pop the rear seat up and remove it and then the cover is held on with 4 10mm nuts. If you have to remove the pump (passenger side) or regulator (drivers side) then you will need a fuel pump ring removal tool. I use the Bavarian auto ring removal tool.

[SnapCoupe]

Originally Posted by 9krpmrx8

Stupid easy, just pop the rear seat up and remove it and then the cover is held on with 4 10mm nuts. If you have to remove the pump (passenger side) or regulator (drivers side) then you will need a fuel pump ring removal tool. I use the Bavarian auto ring removal tool.

Nice, thanks for the help! I'll crack it open this weekend and check back with an update after.

[SnapCoupe]

Just checked both the driver and passenger sides of the tank and they are both dry as a bone on top. Back to square one I guess.

[Kev0]

I had a long crank before but ended up being the battery. Replaced it and fixed the long crank. This happened during the "cold" season in sunny Socal.

[SnapCoupe]

Originally Posted by Kev0

I had a long crank before but ended up being the battery. Replaced it and fixed the long crank. This happened during the "cold" season in sunny Socal.

Brand new battery installed. Just about brand new everything actually, minus the HPFP and LPFP.

[juld0zer]

Originally Posted by SnapCoupe

I have been trying to figure out my long crank issues ever since I purchased my car around a year ago. The symptoms are as follows: Whenever the car sits for more than 6 hours around 50% of the time upon the first press of the start button, the car will continue to crank but refuses to start. If I press the button again to stop it and once more to try to start it again, it will fire up immediately. When it is colder than about 50 degrees F outside, this will happen just about every time the car sits for longer than 6 hours.

Without blindly replacing components, I have been trying to diagnose the issue to get to the bottom of it. I have ran multiple fuel system pressure tests on BMW's diag equipment, but all of them come back normal. I have logged plenty of runs with multiple styles of driving on MHD and my rail pressure is exactly where it should be. Unfortunately my car (2011) does not have a low pressure fuel sensor, so there is no way to tell if the LPFP is feeding the HPFP as intended. My best guess as of right now is that the LPFP is slowly dying out and upon initial priming of the HPFP, the LPFP does not have enough pressure to push the fuel to the HPFP. Hence why the second attempt to start always works.

In regards to these cars, the HPFP is always the one to go first. It's the weak link and replacing it seems to fix most fueling problems that people tend to have. Though, I am curious to hear if anyone has replaced a LPFP on a 2011 without the LP sensor. If so, why did you replace it? How did you know that the LPFP was the culprit? And, had you already replaced your HPFP prior?

Thanks guys!

Did you do the testing or an actual dealer do the testing?

The rail pressure can be observed on cold start. It should reach setpoint pressure very quickly if the pump is good. Of course, multiple cold start tests would be useful to eliminate a fluke.

[SnapCoupe]

Originally Posted by juld0zer

Did you do the testing or an actual dealer do the testing?

The rail pressure can be observed on cold start. It should reach setpoint pressure very quickly if the pump is good. Of course, multiple cold start tests would be useful to eliminate a fluke.

I had a tech show me how to do it the first time, then I did it myself at a later date. I have logged with MHD on cold starts and its difficult to get a good reading as MHD stops logging if you try to stop the car from cranking and restart it again.

[bluesy_cube]

My 2011 E92 335i is having the very identical issue.
Long crank for the cold start, usually taking 2~3 seconds, but instant ignitions on any other time.

I don't think it is HPFP, but was doubting the LPFP.
I'm gonna check out fuel pressure regulator sometime soon.

[sd306]

Mine had long cranks and eventually wouldn't start. I thought it was the HPFP or the LPFP. I have the Fuel-It Stage 2 LPFP.

For me, the issue was the EKPS Module. The module that controls the LPFP. However, mine could have died from using the upgraded pump.

BTW I replaced my EKPS module with a used one from Ebay and programmed it. It came from a 328i that had about 50K miles. I paid around $75 for it. Dealership quoted $1200 for the part and install..

[LoneWolfPistol]

I had a similar problem, I tried changing my spark plugs and coilpacks and it stopped. but now I have the limp mode problem after I hit over 130. Good luck to you

[weehe126]

Originally Posted by Simplev33

I had a similar problem, I tried changing my spark plugs and coilpacks and it stopped. but now I have the limp mode problem after I hit over 130. Good luck to you

You are probably hitting the speed limiter.

[LoneWolfPistol]

Originally Posted by weehe126

You are probably hitting the speed limiter.

Correct sir thank you, Bad tune didn't stop VMAX