2002 330xi engine shuts off few seconds after starting

[rashedsaud]

Hello, I bought my first BMW last summer. It's a 2002 330xi Auto/Steptronic (E46 chasis). First of all, I hardly know anything about cars, let alone BMWs. Here's the weird problem I had:

I exited off of highway, and took a sharp right turn at the end of the exit ramp. I was probably going 20-30 mph when I took the turn. A few seconds later, RPM started to jump up and down as I was trying to accelerate to change gear. Eventually, within a minute, the engine shut off. I restarted and I was able to drive another 200 yards, with the bumpy ride until the engine shut down again. After that, engine shut off a few seconds after I started as if there is no gas.

I WAS low on fuel, computer showed 30 miles till empty. Had the car towed to the dealer. Next day, the service guy calls, after the technician had inspected the car, and said that the technician's investigation led him to believe that the problem occurred right after I took a right turn. I verified his observation.

Well, the explanation was technical and I had no idea what he was talking about. He said that the fuel tank has two sections. In the "saddle tank" (the section on the right), some fuel is reserved for injecting (??) or some other purpose. When I took the sharp right turn, that fuel was displaced and the engine shut off because the saddle tank couldn't inject fuel or something?? The problem was further exacerbated with the low fuel in the tank.

The explanation sounded pretty good especially to a layman like me. However, I contended that it shouldn't have happened because the computer still showed 30 miles till empty. The service guy first told me I wasn't supposed to run so low on fuel, and he was going to give the car back and told me to make sure I keep the fuel tank at least 1/4 full. I wasn't satisfied with that because that's not going to solve the problem. In the meantime, the technician decided that he wanted to do some more testing.

So that's where it stays now. I will find out more next week. My questions are:

1. What is the expert opinion out there about the problem? Should I just shut up and always keep the tank at least 1/4 full?

2. I have been trying to get a picture of the fuel tank and a description of how it works on the internet. Any idea if that information is available anywhere?

Thank you in advance for taking the time to help and educate me.

- Rashed -

 

[Kirby]

It definitely sounds like you just ran out of gas. The computer calculates the remaining distance based on recent fuel consumption, speed, engine rpm, and remaining fuel. With an estimate of 30 miles to go, it thought you had only about 1 gallon left in the tank. Taking a sharp turn in any car with only 1 gallon in the tank could cause it to starve.

You also should recognize that all of the sensors and calculations involved are not absolutely accurate. Instrumentation error in cars can be as much as 3% to 5%. You may have really had only 1/2 gallon of fuel, or less. I don't think there is a problem with your car.

 

[Average Jae]

yup, i think the tech was pretty spot on. i don't know about the whole 1/4 tank bit, but i think he was just saying it to REALLY make sure. if there is a down side to the whole fuel injection system, is the fact that the minute they get no gas, it just goes, "ok quitin time" and sputters out.

it may just be an urban legend, but someone told me that if your fuel injector is completely tapped of gas, it won't restart until after the dealer resets something or another. who knows the validity of that, but i try to fill up once i hit a quarter mark. i don't want to find out first hand.

i don't think there's anything good to come out of going down to the last drop of gas anyway. altho i do it sometimes out of laziness, or by sheer gas price shock as of late. (but i try to remind myself that gas prices always average out.) i try to stay above the 1/4 mark, esp during winter months. you never know when you'll get stranded, for whatever reason, so at least having some gas in reserve will keep you warm while waiting for help to arrive.

 

[Bmw 325i 7803]

I think you just ran low on gas, and should keep it over the 1/4 mark. Especially since the gas is what cools the fuel pump, even the owners manual states never to let it run below 35 estimated miles remaining as it's bad for the engine. I personally like keeping the car full, or at the least filling up when it goes a bit below 1/4.

I really don't see the benefit or pleasure from letting the car run empty.

 

[jrt67ss350]

it may just be an urban legend, but someone told me that if your fuel injector is completely tapped of gas, it won't restart until after the dealer resets something or another. who knows the validity of that, but i try to fill up once i hit a quarter mark. i don't want to find out first hand.

This is true of diesels, but not gasoline engines. If a diesel runs dry, the fuel system must be primed before the high pressure diesel injectors can work - this requires a tow to a shop with the equipment to do this. However, if a gasoline vehicle runs dry, all it will require is more gas in the tank and a short while cranking the engine before the fuel system builds the pressure back up to feed the injectors. A gasoline vehicle doesn't require a visit to the dealer after running out of gas - although this is horrible for electric fuel pumps and will vastly shorten their lifetime.

 

[rashedsaud]

Thank you all.

Thanks a lot for your comments. I appreciate your help. I will post the final analysis of the technician, if anything new, as soon as I hear back from him.

- Rashed -