2006 BMW 325 - Hard Start After Sitting

If the car sits more than three or four hours it is hard to get it to start. Cranks over fine. But it takes forever tor get going and run. Sometimes you have to crank it five ir six times for twenty seconds before it finally starts. Very frustrating. Check engine light was on and the codes were intake and exhaust cam synchronization faults and random misfires. Once it’s going it runs perfectly and will restart right up everytime. It’s been a good car for 175K miles and does use any oil between changes. I did replace the intake cam sensor and cleared the codes and the check engine light is is off after a week but it didn’t help with the long cranking. It’s the N52 engine. Not the M54.
Plz help. Thanks. Spider

The next time the vehicle sits for a long period of time, turn the ignition switch to the run position for two seconds, and then turn the ignition switch off.

Repeat this a half dozen times and then try starting the engine.

If the engine starts right up, it points to a problem with the fuel pump assembly.


With any luck you’ve already solved the cam sync problem and the only remaining is a problematic fuel pump. When you turn off the engine the fuel pressure which feeds the engine is supposed to hold. That’s so next time you start the engine there’s plenty of fuel appropriately pressurized & ready to be injected. There’s a one-way check valve which prevents the fuel from draining back into the tank. But sometimes that check valve starts leaking, allows the fuel to flow back to the tank instead of staying where it is supposed to stay. That check valve is usually part of the fuel pump ass’y.

I wish. Fuel pressure and volume are in spec and the check valve isn’t leaking down. Thanks for the reply. Spider

Takes a lot of cranking to start when the engine has been sitting, but starts ok when the engine is completely cold, and the fuel pressure tests ok? hmmm … my next guess, either there’s a compression problem or ignition system problem. Unless there’s a clear reason to believe it’s the ignition system, next step is probably a cylinder compression test. Either that or a shop scan tool/o’scope diagnosis of the ignition system.

How did you correct this problem? Have you re-checked for pending codes?

Just to clarify the only time the engine cranks and runs is after you got it to run warmed up it’ll fire off every time after it sits for a couple hours it gets harder and harder to crank overnight it takes a while. Ignition and trigger for the injectors are both OK. Compression is even and strong.
This one is messing with my head to say the least. Spider

Intake cam sensor replacement cured the synchronization codes. I did get the random misfire codes back a couple of times. But nothing cylinder specific. The spark plugs and ignition coils were swimming in oil from a leaking valve cover gasket but I’ve got that all cleaned out and it’s still doing the same thing.

Thanks for the help. Compression Fuel and air. I have to be missing something. Even checked cam timing while I was doing the valve cover gasket and it was only a little off from chain stretch due to the higher mileage. I’ve seen a lot worse on these engines with no problem. Spider

I had perplexing cranks but won’t start problem w/ my older truck. I tested for fuel, ok. I tested for spark, ok. Compression, timing, nothing wrong there. The only thing I noted from all these tests was the spark seemed to appear a little weaker than I’d expect, reddish color rather than whitish-blue. Spraying starter fluid into the carb caused the engine to pop during cranking, like it wanted to start, but still wouldn’t. That led me to do more fuel system tests, but still everything tested ok. I finally discovered the problem. It was in fact a weak spark. The ignition points measured 30 ohms resistance when closed. That resistance should be less than one ohm. This prevented the ignition coil from being fully charged. Once I corrected that problem, started right up and ran perfectly. So maybe you’ve got something happening like that, you got a spark, but it’s a weak spark. That would produce worse symptoms when the engine is cold.