kryan

Well it appears as if i'm not lucky after all. The symptoms are back. Cranks but sounds like its out of timing. Removing the negative battery cable did correct it for a couple of short trips. I've read elsewhere on this site it possibly could be the crank sensor? Does anyone know its location and how I might test it?

Before I do that, I guess I need to check gas and spark. During the cranking process it would misfire. So spark is there right? How do I check for gas?

thanks for any help.....

pcy

I believe 2008 528xi has N52 engine.
Crankshaft position sensor is located under the intake manifold; next to the starter.

If you want to check the fuel pressure, attach fuel gauge to the valve at the end of fuel rail.

seanjordan20

If you want to check f its getting fuel just do what I do. At the end of the rail closer to you there is a cap (looks like where you put air in a tire). Press on it. If it shoots out then it is getting gas. If it trickles out then you are not. I believe that fix was given to you before. There really isnt a way to check the crank sensor I guess. I just bout one from the parts store and put it in if it makes a change then its fixed if not take the part out and return it. The best way I found to get to the sensor is from the bottom it sits on top of the upper pan under the starter. You should see a code if the sensor is malfunctioning though.

kryan

.....the engine started right up today......sooo undependabel thought, i'm scheduled to take a 900 mil trip in April, but not in this condition. No much point in checking the fuel pressure and crank sensor when its running fine.

I keep getting this sense that its the battery. But its cranks real strong. I did perform a load test according to the Bentley manual and the running voltage was 15.30V. The manual claims anything over 14.8 volts is probably a faulty voltage regulator.

Could this be my problem? Does anyone know where the voltage regulator is located? Its not listed in the manual. Is it part of the alternator?

Thanks for all the help

seanjordan20

The voltage regulator should be plugged in on the back of the alternator. If that is failing then the battery light should come on. Part # 12317561924. How old is your battery. If it is 7 years old then replace it.

jtbgonesailing

Don't be overly consurned with 15.3v with the extremely cold temperatures you have been experiencing. The IBS and the balance of the charging system is temperature compensating, ie the colder it gets, the higher the voltage to a point. 15.8-9v range tops. The same with summertime high temperatures, may only be 13.2v or so with engine running on a hot August afternoon.

seanjordan20

+1

kryan

No I do not have a battery light displaying. We bought the car about a 6 mnths ago and I seem to remember the used car dealer stating that he went ahead and changed the battery to avoid problems because it seamed weak at the time.

Is it possible that it was not registered from a FLA to and AGM? I read where it will damage an AGM if its overcharged.

Thanks

twh

I know the BMW technical documents say FLA to AGM without changing the battery type can mess things up. It is more than register, you actually have to change the battery type in addition to register a new battery. But, not sure in real life how prevalent it is. I know my two kids cars have new AGM batteries in place of Flooded batteries and I put an AGM in a friends Corolla. They all seem to be fine after a year.

kryan

My statement of owning the 2008 BMW 528 xi for 6 mos should be more accurately stated at 11 mos. Almost a year, which could be the amount of time it might take to eventually wear down a good AGM battery by overcharging. However at this points its a possible clue as to what might be wrong with this car.

You bring up a good point , does any one have a good handle on the detailed distinction between registering and reprogramming modules when it comes to battery changes? Can it be done with INPA? I must be a real moron because the I can not fully understand some of the threads on this site. The "Idiots guide to INPA helps but some general summary type info is missing.

thanks