Random Stalling Issue-2002 330CI-HELP!!

[mbonder]

I've been chasing a random stalling issue on my wife's 2002 330CI with 119k miles on it for several years. This problem has been a true PITA as it throws no CEL ever. There are no stored codes, I've pulled them after several instances of it stalling, I've also had this confirmed by two different Master Techs at two different independent shops.

When I say random, I mean completely random. There will be times when I'll be at a stoplight and from a standstill it will sputter and die when trying to accelerate forward. Other times I could be shifting from first to second gear and it will sputter and die, I could be cruising along on the highway in the same gear and it will sputter and die. It's totally random and there are no signs that indicate when it'll happen to prepare you for the eventual stall. There have even been times when I go to start it and the engine will spin but won't fire. It'll eventually fire up after stalling or not starting, sometimes it's nearly instantly, sometimes i have to sit there for 10 minutes of spinning the engine. Again, there's no pattern to it at all.

This first happened just over 2 years ago and I naturally thought that the fuel pump was going out. I had that replaced and the car drove fine for around 6 months, then it started happening again. The difficulty is that its tough to have a shop diagnose it as I've driven it through multiple tanks of gas without a single stutter, then I've gone a half mile and it'll stutter to a stall, then a mile to a stutter and stall, and so on.

I pulled a replaced the fuel pump again a couple weeks ago just to be sure I didn't have a defective unit, then replaced the fuel pump relay and the main ECU relay. None of these helped. It'll play games where I'll replace a part and it'll run fine for several hundred miles, but eventually it will stutter and stall.

One of the things that I've had success with is if you immediately take your foot off the gas when the stuttering starts and you are able to coast for a period of 5-10 seconds, you'll most likely be able to avoid the stall and eventually continue driving. So it's as if I have a temporary loss of fuel pressure and then it will catch and be fine.

The only thing I can think of is that there is actually a defect in the wires that feed the pump and if you hit a bump or something you'll get a disconnect and a temporary shut off of the fuel pump, however, its been so random that I can't see this being the case when the car runs fine, I shut it off, and then it fails to restart the next time I'm in it.

Further thoughts I had were maybe the Throttle Position Sensor is failing and the computer is getting the wrong values throwing off the mixture to the point where the engine stutters to a stall, or the computer itself is not sending the proper signal to the fuel pump. Beyond that I have no idea what the hell is going on and I'm about ready to drive the car off the pier into the ocean. It's been a great car, one of the best I've ever owned and has been fantastic for nearly 10 years, but if I can't solve this one soon I'm going to ditch an otherwise fairly low mileage, 3 owner, no accidents e46 for something else as I can't take it anymore and I can't let my wife drive it as I'm concerned that it will stall in the middle of an intersection or on the freeway and she'll get seriously injured.


Please Anyone Help!

[MarcoZandrini]

Have you replaced the fuel filter? The filter contains the fuel pressure regulator. Buy either a mahle or keyser filter from FCPEuro. Both companies supply fuel filters to BMW. Also, get/buy/borrow a fuel pressure gauge that has a long hose. Connect it to the pressure test valve on the fuel rail. Tape the gauge to the windshield to see if the pressure drops just before the engine stalls. Also, get the OBDFusion app for your smartphone or tablet. You’ll need a communications adapter that plugs into the obd2 port under the dash. If your device is iOS get a WiFi adapter. Android works best with Bluetooth. Then search this for fir a thread on OBDFusion in which Balidawg has commented. OBDFusion allows you to log a bunch of different data streams that can be exported and then analyzed in Excel.

[mbonder]

Fuel filter was replaced when the fuel pump was replaced the first time. The second mechanic I took the car to actually got the car to not start one morning so he pulled the pump out to ensure it wasn't spinning when the car wasn't starting. Obviously no pressure in that situation. Eventually the damn thing fires up and pressure is at spec. They took the pump apart to make sure it was in good working order. To my mind this is electrical more than anything else, but the question is where in the stream is it being disrupted?

[Mless5]

I would think you would would have a pending code if that was the case. If I were you I would get one of those cig lighter USB plugins that show the voltage and monitor what happens when it starts acting up again. Was there any work done recently that required disconnecting electrical plugs at injector points?

Further thoughts I had were maybe the Throttle Position Sensor is failing and the computer is getting the wrong values throwing off the mixture to the point where the engine stutters to a stall, or the computer itself is not sending the proper signal to the fuel pump.

[mbonder]

No work performed prior to the first time or the second time. This car has been a great performer, somewhere around 2015-2016 I replaced the shocks/struts as they were getting warn, did control arms, shock mounts, tie rods, sway bar links, sway bar bushing, along with new brakes all around. Maybe a year after that I did all major components in the cooling system. 2 years went by without issue before the stalling began the first time. Only other thing I've replaced outside of trying to track the stalling issue down was the valve cover and gasket because of a leak above the exhaust manifold that was dripping a bit of oil that would burn off and smell bad.

[Mless5]

Unlock your OBD and monitor voltage: https://www.bmw-driver.net/threads/d...nctions.31204/

[jclausen]

Just to make sure have a shop scan the car and see what faults are present

[mbonder]

I've done that, on my own and at two different independent shops, no codes, ever.

[randy72877]

Have you cleaned the idle control valve?

Sent from my S61 using Tapatalk

[Muzz258]

It sounds like an electrical fault to me.

You are not getting any misfire codes, which is interesting. The DME thinks everything is OK. What can stop an engine and not show a misfire code? If it was a fuel injection or ignition problem that did not result in combustion, then the DME would raise a misfire code. No bang detected by the knock sensor as expected.

A soft failing crank sensor could be a cause. It stops, injection and ignition stop as they are not being called by the crank sensor, no misfire codes?

[mbonder]

Now that's one I hadn't considered, worth testing that out.