[wxst]

Hey my e90 325xi has a long crank when starting and sometimes will not start (the temperature outside does not seem like it affects anything). It cranks normally, but it takes longer to start.

I replaced the battery not too long ago and it still reads a full charge so I do not think its the battery.

The starter was replaced only a few months ago for a similar problem, and the car was working great after replacement.

I gave the car to a local mechanic but it starts up fine for him and it has not shown symptoms of long cranking for him once, so he does not know what is causing it.

The mechanic tested the fuel pressure and said the car is getting enough fuel upon ignition so I think that rules out the LPFP (low-pressure fuel pump).

I have no idea what could be causing this and the mechanic can't even see the problem lol. Has anyone else had this problem? What could be causing it to long crank? (maybe fuel pressure module?)

- Eli

[ctuna]

Ground Strap from motor to chassis in Engine Bay.
If it turns over weakly.
To test bypass by using one side of a jumper cable
between motor and chassis.

https://www.e90post.com/forums/showthread.php?t=1690185

Long Crank in the morning but not during the rest of the
day usually indicated weak battery.
If the car sits for long periods of time you need to keep
it on a battery tender. Or if you are doing ultra short drives
that do not allow the battery to charge.

[gbalthrop]

Originally Posted by wxst

...e90 325xi has a long crank when starting and sometimes will not start... It cranks normally, but it takes longer to start...

Hi Eli, Welcome to the Forum!

Questions:
1) How LONG does it crank before firing? Mine always fires & runs within 1 to 2 seconds of the time I press the START Button.
2) When it has a "long crank" or "will not start", does it sputter or fire at all before it finally starts normally?
3) Have you or your shop used any Scan Tool or Software to read Fault Codes, and if so, what codes appeared?
3a) If a Scan Tool or Software was used to read codes, can you provide the Brand & Model of Tool, or Name of the Software
3b) Do you have a Windows Laptop and are you willing to take the time to download & install Diagnostic Software (INPA or ISTA -- FREE download) and pay $20-$45 for a K+DCAN cable to connect the USB port of your computer to the OBD II Socket of your BMW? That will give you Factory- or Dealer-Level Diagnostics.
4) When did ANY issue with either (a) Long Crank or (b) No Start at all BEGIN?
5) What work was done on the vehicle just before either fault first occurred?

There are obviously MANY possible causes of an intermittent crank but NO START condition. If there are NO Fault Codes saved in DME (Engine Control Module) Memory, you have to "catch the fault in the act" with proper software that can read Terminal Voltages, to see where the fault lies.

Most common scenario for a condition such as you describe is failure of the DME to receive a signal from the Crankshaft Position Sensor, or a Camshaft Position Sensor, both of which are needed to "Time" Injector Pulse and Spark Trigger Pulse to the Coils. If the DME doesn't get either of those signals, it basically says "I give up".

Thing is, lack of proper signal from either of those sensors usually results in a Fault Code saved in the DME Memory which can be read by even a generic, cheap P-code reader, such as P0335 or P0340. That fault code doesn't disappear just because the engine starts the next time. It remains in DME Fault Memory UNTIL it is cleared by a Scan Tool.

Perhaps with answers to questions above, someone can suggest "next steps".

George

[wxst]

Originally Posted by wxst

Hey my e90 325xi has a long crank when starting and sometimes will not start (the temperature outside does not seem like it affects anything). It cranks normally, but it takes longer to start.

I replaced the battery not too long ago and it still reads a full charge so I do not think its the battery.

The starter was replaced only a few months ago for a similar problem, and the car was working great after replacement.

I gave the car to a local mechanic but it starts up fine for him and it has not shown symptoms of long cranking for him once, so he does not know what is causing it.

The mechanic tested the fuel pressure and said the car is getting enough fuel upon ignition so I think that rules out the LPFP (low-pressure fuel pump).

I have no idea what could be causing this and the mechanic can't even see the problem lol. Has anyone else had this problem? What could be causing it to long crank? (maybe fuel pressure module?)

- Eli

Forgot my login info so I was unable to reply to the responses but thank you for your advice. Now that I can post again I thought i’d give an update.

The car seemed better in the hot weather last summer (2020) but still struggled to turn over on a start. Last summer I brought the car in to replace the grounding straps. A week later brought it to the dealership where they replaced the VANOS solenoid valves. Still, nothing seemed to fix the problem.

After living with this annoying issue and driving it around the past winter, I’ve discovered a couple things. The problem is amplified in cold weather and sometimes could not get it to even start. I’ve not had much of an issue since the weather has gotten warmer. Also, I’m almost certain it has something to do with the fuel system. I tried to jump it one cold morning after multiple attempts of the cars long crank. I thought the battery was dying (lights flickering on dash), but all the lights came on fine and the car still cranked. No start. I can also smell a gas like fume when I try to start it or the car turns on.

I’ll post a picture of the previous work done on the car and some things i’d like to get checked. I also have a video of the cranking problem from last winter. When I start the car, the rpms go up and down but don’t get passed 1000. I try to time it right and press the gas when the rpms go up and if I catch it right, the car turns over. That’s what I tried in the video but was unable to start it that day. I also thought i’d mention the rpms because you can’t really see it in the video.

Hope this additional info helps and I’d appreciate any insight or advice towards this problem. Thanks in advance.

Video:

[wxst]

Also, I occasionally get a check engine light with codes P0420, P0430 but I am unsure if this is related, as if a faulty o2 sensor could cause this? I am not sure.

[JonOhh]

O2 is not active or doing anything other than heating up upon startup, so I'd rule that out.

I know you said a mechanic checked the fuel pressure bit man, it really sounds like a fuel related issue. Not going to guarantee it, but it is very likely.

These cars run much higher fuel pressures than many typical american fuel injected vehicles. Where 40psi may be spec for an american vehicle, these run in the 70+psi range. If your mechanic is used to working on american vehicles, he may not realize the pressure spec is as high as it is. As far as I am aware, there is no fuel pressure sensor on N52 cars. If fuel pressure is insufficient or below what the dme expects, a lower than calculated volume of fuel will be injected, and until the O2s have heated up, the dme will have no way to know and compensate for this.


So that being said: check fuel pressure regulator and pump next. Your paper says the fuel pump does not prime upon unlock- it should. Has it always done this, or is it new behavior? If it is new behavior it may be electronics related.