car starts then dies

[hawkeye00021]

I searched the forums for the exact same problem and came up empty. I did find one post on the googler where a guy with an E46 had to replace his fuel pump for what sounded like my issue but I wanted to run it by you guys.

Basically, I start the car and the engine instantly shuts down unless I hold down on the accelerator. It seemed to just start out of nowhere (besides the ridiculous heat we are getting) just a few hours ago. I drove it home just fine because it stays on if it is moving but the AC did seem a bit on the weak side even factoring in the heat. I drove it pretty hard this morning but it was just fine at lunch time. Also, all of the electronics seem to have plenty of power possibly pointing away from the battery although I suppose anything is possible. It isn't showing that any codes need to be read, but I don't have a code reader to double check. Unless someone has a magical idea it goes to the shop tomorrow.

[04z4]

I'm not sure if this situation is the same as yours, but I recently had a one-time starting problem. Here is my description, copied from another forum:

Something weird happened today and I am posting my experience in hopes that it might help someone else one day (and maybe someone else can share some insight).

I changed the oil today in my Z4 and rotated my tires. The engine was 'cold' from sitting overnight but the ambient air temperature was about 85 degrees F so it was not all that cold. Humidity was high, for whatever that is worth.

After replacing the oil filter and refilling with oil, I started the engine briefly and ran it for about 20 seconds in order to distribute the oil throughout the system so I could get an accurate level check on the dipstick and add a little more oil to bring it up to the proper level. About 15 minutes later (after rotating the tires and checking the fluid levels) I went to start the car to pull it out of the garage.

Much to my dismay, it would not run. The engine cranked fine, but would fire up for a second or so and then die. I tried 2 more times (same result) then stopped to consider the situation. I looked under the car for an oil puddle (thought I might have forgotten to re-install the drain plug) and then checked the oil level again and saw that it was fine.

I tried to start the car again several times, with the same result. Each time it would crank and then run for just an instant before dying.

Some research on the Internet told me that running the engine for a very short time like I did could could cause it to not want to start up again. Perhaps the cylinders get flooded with gas or condensed moisture and the engine has not run long enough to warm up at all and evaporate the gas or moisture that is in the combustion chambers.

One posting I read said to hold the gas pedal to the floor and try to start it, which would supposedly cut off the flow of fuel and allow the combustion chambers to clear. I tried that and the engine immediately fired up and revved to 6000 rpm or so before I could release the gas pedal (the cutting off the fuel part might not have been accurate). After I released the gas pedal, the engine settled into a normal idle. I let the engine warm up for about 5 minutes or so then shut it off. An hour or two later I was able to start it again without any trouble and drove it to the grocery store (10 minutes away) and back.

The resulting lesson for me is that if I start the engine when cold, I'll let it run for several minutes before shutting it down to try to avoid the situation in the future.

----

Someone responded with this:

This is a common problem with all BMW engines...some more than others.

Pushing the gas pedal I don't know exactly what it does (as to cutting off fuel) but it helps the engine fire.

I always let the engine run for at least a minute or so...rev to 2000 a couple times and you should be fine.

In this situation you just floodded the spark plugs

[hawkeye00021]

Well that seems to have done the trick. I did smell something funny but I think it was just fumes from not having my garage door all the way open. It's good to have carbon monoxide detectors all over the house.


Thank you so much for that insight. I hope the way I phrased the question links people back to this thread easier. I searched several different ways and couldn't come up with anything. Thank again.

[3aceziam]

I have a 2010 3.0 that is doing the same thing. 100% baffled by this . Holding the accelerator down had it continue to run but I don’t understand how this would fix it

[SonnyA85]

I have a 2010 3.0 that is doing the same thing. 100% baffled by this . Holding the accelerator down had it continue to run but I don’t understand how this would fix it

there is something to do with the throttle that people usually clean regularly.

it's near the disa valve iirc underneath it maybe. i can't remember now been a few years. but apparently that clears up issues for folk with these sorts of issues.

[enuff_zed]

I have a 2010 3.0 that is doing the same thing. 100% baffled by this . Holding the accelerator down had it continue to run but I don’t understand how this would fix it

there is something to do with the throttle that people usually clean regularly.

it's near the disa valve iirc underneath it maybe. i can't remember now been a few years. but apparently that clears up issues for folk with these sorts of issues.

Idle Control Valve.
Need to pop the DISA off for better access, then it's fairly straightforward to remove. It should move freely but they get gummed up, so spray with carb cleaner or equivalent until it rattles when you twist it.

[SonnyA85]

I have a 2010 3.0 that is doing the same thing. 100% baffled by this . Holding the accelerator down had it continue to run but I don’t understand how this would fix it

there is something to do with the throttle that people usually clean regularly.

it's near the disa valve iirc underneath it maybe. i can't remember now been a few years. but apparently that clears up issues for folk with these sorts of issues.

Idle Control Valve.
Need to pop the DISA off for better access, then it's fairly straightforward to remove. It should move freely but they get gummed up, so spray with carb cleaner or equivalent until it rattles when you twist it.

Is there any difference between carb cleaner and brake cleaner?

I'm getting the egr valves cleaned on another car and wondering if I should get some of that as I got 12 cans of brake cleaner for the job.

Need the EGR pipe, egr cooler, egr valve and Intake manifold cleaned otherwise it gets stuck open causing the engine to overheat.

[enuff_zed]

there is something to do with the throttle that people usually clean regularly.

it's near the disa valve iirc underneath it maybe. i can't remember now been a few years. but apparently that clears up issues for folk with these sorts of issues.

Idle Control Valve.
Need to pop the DISA off for better access, then it's fairly straightforward to remove. It should move freely but they get gummed up, so spray with carb cleaner or equivalent until it rattles when you twist it.

Is there any difference between carb cleaner and brake cleaner?

I'm getting the egr valves cleaned on another car and wondering if I should get some of that as I got 12 cans of brake cleaner for the job.

Need the EGR pipe, egr cooler, egr valve and Intake manifold cleaned otherwise it gets stuck open causing the engine to overheat.

Not a lot of difference.
I'd suggest try a small sample first. You want to make sure the cleaner lifts the crap so you can wipe it away, but the cleaner itself doesn't leave any residue.