Starting Issues - 4.8is

[mywidebody02]

My buddy had the same problem and it was the dme sowtware that needed upgrading. It was an 05 with a 9/04 production date and 4.4.

[imola4.8is]

Originally Posted by mywidebody02

My buddy had the same problem and it was the dme sowtware that needed upgrading. It was an 05 with a 9/04 production date and 4.4.

Interesting. I wonder if there is a TSB for a software update on the 4.8is?

I changed the fuel filter yesterday, more so because the car has 71k miles and thought it would be a good thing anyways. Not expecting it to fix the starting issue......

[TwinsPoppa]

Imola ... Did you read the post about DME software from killcrap in the thread below?

http://www.xoutpost.com/bmw-sav-foru...ems-4-8is.html

[imola4.8is]

Originally Posted by TwinsPoppa

Imola ... Did you read the post about DME software from killcrap in the thread below?

http://www.xoutpost.com/bmw-sav-foru...ems-4-8is.html

Interesting that he still hasn't figured out the problem. I may just be taking it to the stealer next week.....

[Patryk1098]

I have a (U.S.) 2005 X5 4.8is. I'm not certain of the production date -I haven't dug into that just yet.

I have been experiencing the same starting problem. If you're already familiar with it, please skip the following paragraph:

Problem Description:
In the winter / colder season (temps below 50F), once the car is fully warmed up, I park it for roughly 80-100 minutes. When I come back and attempt to start the car, it initially sputters very briefly as the engine cranks, then it simply continues to crank. The starter doesn't stop, but the engine isn't firing, just constantly turning over. I don't want to kill the battery, so I turn the key back to stop the starter. Repeated attempts provide no change, and depressing the gas pedal (or not) seems to have absolutely no effect. In fact, there appears to be no rhyme or reason as to why it starts, other than when I hear it start to sputter (very very lightly), I depress the gas and pray it "catches".

Important Additional Notes:
Once the car starts after having this issue, it runs fine and starts back up without hassle if turned off.

The car has cut out on my while stopped in traffic. No sputtering, no warning, engine just stops.

No fault codes were recorded when the starting problem occurred.

Fuel tank has been at varying levels; this happens on a full tank, near empty, and somewhere in the middle.

Fuel quality does not seem to be an issue (or at least I don't suspect it to be one since this seems to happen regardless of where I get gas). I've always run premium.

This never happened during warmer weather (I've had the car since August).

I leave the car parked outside (no garage).

The car never sputters while driving, idling, or any other time: There are no precursors to this problem.

There is no fuel smell when the car won't start (or otherwise).


After reading this thread, I brought my X5 to my local dealership. I explained the problem I've been having and that my research has suggested that updating the DME software might help. I allotted 2 hours for the technician to attempt to diagnose the problem. The service advisor (whom I believe is actually very knowledgable) mentioned that it could be leaking injectors, though if I don't have consistent fuel smell, they're not likely to be the cause. It could be fuel pumps (there are two, one in the fuel tank and one outside), fuel filter, etc. Or, it could be the DME as I've suggested.

They tested the external fuel pump and it behaved normally. The updated the DME software (there was an update to a newer software version) and suggested that if the starting issues resurfaces, that it may be worthwhile to test the fuel pump within the gas tank.

Thus far, the engine seems to run smoother all around. While the change is ever-so-subtle, I notice it most when the car is cold and on throttle response. The previous DME software had the car respond sluggishly when I attempted to depress the gas to accelerate. Now, the car seems to respond more quickly under both subtle and aggressive acceleration.

I don't think the DME update gave me any more power (though it might; after all it IS the engine management system), but it definitely made the engine run a bit smoother.

I haven't encountered the starting issue, but it has only been a few days. The next two months will tell.

Programming the DME and testing the external fuel pump can be done within 2 hours of labor -so don't let your dealership rape you. They may need the car for the day since the DME updates tend to crash ~70% of the time and require the update to restart. The actual software update can be run and left alone -and requires some time (so I'm told), but a technician doesn't need to waste time sitting and watching it.

[SlickGT1]

Did you guys ever check your plugs? I used to get this in the winter as well on a 328is. The damn thing would crank and crank and crank. I would just pray for something to catch. I thought I was getting condensation in the fuel, and it was freezing. Put in a shit ton of dry fuel, no change. I forget how many things I went through.

So then I started from the beginning. You need spark, fuel, air. I was getting fuel, I could smell it out the exhaust. I was getting air, I even disconnected the intake all the way to the TB, and tried starting it that way.

Turned out to be spark. Spark plugs to be exact. Replaced the plugs, and completely forgot about this issue.

This car is way more complex though, so can't say for sure. I also have a 4.8is, but don't have this problem. I just did my plugs, and my car sits in a 60F garage all the time. Well except when I travel.

I had this happen to me once when I cleaned the maf. Wouldn't start till the 4th attempt.

Is it possible the TB is sticking, freezing? I don't think we have IAC on our 4.8is. My logic is that after your drive, shit condenses on the TB, Maf, freezes up and causes you not to get enough air. A cleanup for both might do the trick. Plus it is cheap since all you need it CRC maf cleaner and TB cleaner.

[Patryk1098]

Originally Posted by SlickGT1

Did you guys ever check your plugs? I used to get this in the winter as well on a 328is. The damn thing would crank and crank and crank. I would just pray for something to catch. I thought I was getting condensation in the fuel, and it was freezing. Put in a shit ton of dry fuel, no change. I forget how many things I went through.

... *snip* ...

All great suggestions, but the behavior I'm experiencing doesn't seem to quite fit. If the MAF was dirty, then the car should still be able to start, but stall out and/or sputter -either while starting or idling. At least that's the behavior my father's Mercedes ML320 exhibits. ...granted they're completely different makes.

Temps weren't cold enough for anything to freeze (3/4 times, temps were > freezing). Also, if the plugs were bad, the engine would exhibit a loss of power (pistons not firing) while running.

The behavior I'm experiencing really seems like it's computer related. When the car doesn't start, it doesn't even provide a hint of starting. It just turns over. And the two times it cut out, the engine just stopped. If sensors were bad or dirty, there would be some combustion -as well as a check engine light. In the 335's when the HPFP (High Pressure Fuel Pumps) fail, the engine sputters while it cranks, starts, idles poorly and stalls out. When MAF sensors are dirty or have buildup, the temperature of the thermistor or hotwire in the sensor would provide a false reading, which would allow the engine to run, but very poorly (see http://www.autoshop101.com/forms/h34.pdf).

You're entirely right about the plugs. If they're dead (most or all), then I'd have the same behavior (not starting), but the car runs totally fine otherwise. It's a very unpredictable problem and one that I can't re-create on command. Also, its not constant. The car starts up and runs 97% of the time and has only failed to start 4x in the past 5+ months --and all just recently over the past 2 months.

I'm not trying to shoot you down, I'm just thinking through the problem, symptoms and possible causes to make sure the forum has as much info as possible. Thanks, and please correct me if I'm off base on any of my statements.

[nitrorocket]

I'm a mechanic... If I were to dive into this I would start by hooking up a fuel pressure gauge and also checking for spark when I know this will happen. This will eliminate these as a factor, but it could very likely be either one, knowing will throw you in the right direction for the remaining diagnosis.

[SlickGT1]

Originally Posted by Patryk1098

All great suggestions, but the behavior I'm experiencing doesn't seem to quite fit. If the MAF was dirty, then the car should still be able to start, but stall out and/or sputter -either while starting or idling. At least that's the behavior my father's Mercedes ML320 exhibits. ...granted they're completely different makes.

Temps weren't cold enough for anything to freeze (3/4 times, temps were > freezing). Also, if the plugs were bad, the engine would exhibit a loss of power (pistons not firing) while running.

The behavior I'm experiencing really seems like it's computer related. When the car doesn't start, it doesn't even provide a hint of starting. It just turns over. And the two times it cut out, the engine just stopped. If sensors were bad or dirty, there would be some combustion -as well as a check engine light. In the 335's when the HPFP (High Pressure Fuel Pumps) fail, the engine sputters while it cranks, starts, idles poorly and stalls out. When MAF sensors are dirty or have buildup, the temperature of the thermistor or hotwire in the sensor would provide a false reading, which would allow the engine to run, but very poorly (see http://www.autoshop101.com/forms/h34.pdf).

You're entirely right about the plugs. If they're dead (most or all), then I'd have the same behavior (not starting), but the car runs totally fine otherwise. It's a very unpredictable problem and one that I can't re-create on command. Also, its not constant. The car starts up and runs 97% of the time and has only failed to start 4x in the past 5+ months --and all just recently over the past 2 months.

I'm not trying to shoot you down, I'm just thinking through the problem, symptoms and possible causes to make sure the forum has as much info as possible. Thanks, and please correct me if I'm off base on any of my statements.

Right, on my old car, when the plugs were bad, it started most of the time, but when it started getting cold it would do the same as the OP. Once running, it ran totally fine. No loss of power or anything. My logic was that there was something up with the plugs. Once the car starts to crank, the cylinders get flooded with fuel, plug gets soaked, and doesn't want to fire for anything. That is why after sitting, the fuel maybe evaporates a bit, and then you might start up. It is worth a shot to check the plugs, at least I would give it a shot.

[Patryk1098]

Originally Posted by SlickGT1

Right, on my old car, when the plugs were bad, it started most of the time, but when it started getting cold it would do the same as the OP. Once running, it ran totally fine. No loss of power or anything. My logic was that there was something up with the plugs. Once the car starts to crank, the cylinders get flooded with fuel, plug gets soaked, and doesn't want to fire for anything. That is why after sitting, the fuel maybe evaporates a bit, and then you might start up. It is worth a shot to check the plugs, at least I would give it a shot.

Point taken. I'll check them out if this happens again. Thanks for the added information. I'm at 90k, so I should probably replace the plugs anyway.