Startup issues

[esafaeian]

Really? Are there any other things I can test to determine if it is the fuel pump? I did have an issue leading up to this sometimes where I would turn the key and it seemed as though there was a slight lag before the car would turn over..

[esafaeian]

Don't know if this makes a difference, but the first time this happened was right after I left my car to get washed at a local car wash place... (left it there before without any issues and it was an outside wash only, no reason for them to open the engine bay).

[esafaeian]

Here is another video showing a sound it makes when the key is turned to position 3 (not fully to turn on the car), is this sound normal? I don't think it's coming from the starter, it's under the manifold area?

[youtube]https://www.youtube.com/watch?v=9n7Wq3L8qIU[/youtube]

[ph001]

Looking at your first vid, the starter engages ok and turns the engine over so doesn’t seem like the problem. 2nd vid is the disa valve reseting, It’s common failure point on the M54 but not so much on the N52. Fuel pump seems like a bit of a stab in the dark. Defo not a common failure point on the Z so very unlikely imho.

[esafaeian]

So are you saying the disa valve could be failing? The first attempt in the video you can hear the car not turning on and the clicking, not sure if it’s battery or starter. I’m going to test to see if it’s the battery by starting it with everything turned off (auto headlights are usually on) and see if that helps, so far today haven’t had any issues starting the car.

[ph001]

So are you saying the disa valve could be failing? The first attempt in the video you can hear the car not turning on and the clicking, not sure if it’s battery or starter. I’m going to test to see if it’s the battery by starting it with everything turned off (auto headlights are usually on) and see if that helps, so far today haven’t had any issues starting the car.

It certainly sounds like the DISA valve changing state but that's not to say it's failing - might be normal operation. I would check on mine but really need 2 people to do it so would have to be this evening. I can't quite hear the issue you mention in the first video but you are right to eliminate the battery as that causes all sorts of weird issues on the N52, I'm not sure just trying it with the lights off will be conclusive enough. The two other common culprits for what you describe are the ignition switch or the starter solenoid.

It's also a little odd that you say this all seems to have started after the car was washed - probably just coincidence but we know that the eccentric shaft sensor can give starting problems if the connector is contaminated with oils or fluids, worth a check to see if it's dry.....

Have you had a code reader on it? Any of the below coming up would confirm the eccentic shaft sensor:
2A37 Valvetronic, eccentric shaft sensor: plausibility
2A47 Valvetronic, eccentric shaft sensor: plausibility
2A43 Valvetronic, thermic overload protection: warning threshold
2DED: power management, standby current control
2A38 Valvetronic, actuator: sluggish or open circuit

bmw-eccentric-shaft-position-sensor2.jpg (117.37 KiB) Viewed 711 times

[esafaeian]

Thanks mate I'll try and get that checked up when I take the car to the mechanic. I just hope it's nothing too major, I've had no issues turning it on all day today (with the only thing being done differently is making sure all electrics are off when switching on the car).

I've got 130k km on the car and just hope it's not going to be a money pit for me as it's my first Euro and I've come from pretty reliable jap sports cars... :O

[ph001]

Yeh, pretty simple job to inspect that sensor - bit more of an arse to change it but I have a good guide for it if you need. Note, that the car should still turn over fine but it just won't catch properly and start. The engine can also sound a little odd when turning over as basically the valves are not in the correct position and you get low compression. Usually the vibration from trying is enough to reset the valvetronic motor / sensor and it starts right up next time.

The car not turning over on the starter immediately when you turn the key is perhaps a different issue which is more likely to be ignition switch or starter motor.

These problems are not particularly common place on the N52 though - it's a very reliable engine on the whole (once the electric water pump is replaced).

[esafaeian]

Thanks for the help mate, I'll get in touch if I need the guide. Yeah the main reason I decided to go for it (other the the looks) was what I had read online about the engine reliability. I haven't changed the water pump yet but I'm monitoring temps on the dash (usually sits between 95-105oC when warmed up) and will get it sorted if I see it starting to rise higher.

[esafaeian]

Hey guys, so I've been monitoring my battery voltages last few days. Seems I get between 13.5-14.2v when the car is on (sometimes drops to 12.9 if I turn on air con), but when the car is off the voltage this morning read around 12.1, ,12.2 highest and dropped to 12ish, dipped as low as 11.8/9 when I turn on the auto lights... Is this getting on the low side for the battery voltage? Could this be causing my intermittent start issues? I haven't had issues tuning the car on last few days, but I've been making sure everything including auto lights were switched off.

[ph001]

Does sound a bit low, ideally it should sit around 12.4V when switched off after a decent drive. I think I’d be changing the battery just to eliminate it if nothing else. It’s a whole lot easier to do than the other stuff.

[esafaeian]

I’m suspecting it may be the battery, the volts are about 12.2 with auto lights off and the car has been starting ok, as soon as the auto lights are on the bolts dip to 11.9-12 volts, I’m thinking the times the car would struggle starting are when the auto lights have been on. Will continue to test and will let you guys know what happens. Another point is when I turn the car on the volts will dip below 10 for a fraction before slowly heading up to the 14 or so volts it sits one when the car is on.