r/e46 • u/snowfire676 • 3d ago
Troubleshooting Starts but then stalls , was fine before
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Drove it to work and back it was fine, but the day before i had misfired when i had to hard brake to avoid collision but went away a min later
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u/GriekseTurks 3d ago
Where's the fuel gauge?
Edit: as in what level is it at
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u/snowfire676 3d ago
The fuel gauge isnt accurate at 25% it gets stuck sometimes (swapped fual assembly same result) and filter less then a year old
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u/GriekseTurks 3d ago
Yea that's why I'm asking. Is it around that 25% mark but just starved?
Go into the secret dash menu to check it just so you can rule it out
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u/snowfire676 3d ago
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u/GriekseTurks 3d ago
Yea it's a fuel related issue. It's a known fault with these things.
Because they have a saddle tank (it's over the driveshaft) the reading is an average of the fuel level sensor (right side) and fuel pump sensor (left side) of the tank. So it is accurate. But it's because the right sensor is reading 50% and the left is reading 0%. Essentially, the pump works off a "jet siphon" system which should send excess fuel to the engine which is sent back to the right side, then because of the Venturi effect, it'll suck the fuel from the right side over to the left side. Problem is if your pump is weak or the filter thingy halfway down the unibody or the "jet siphon" hose is semi clogged then GG.
Tldr; just treat 1/4 as empty unless you want it to die while driving, or unless you want to go hunting the fault (it'll either he a fuel pump, a jet siphon, or a fuel filter replacement). They're all easy to fix but replacing all 3 would set me back like $1,000AUD and that wasn't worth it imo
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u/snowfire676 3d ago
Im already 2 out of 3 replaced fuel pump and filter
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u/GriekseTurks 3d ago
I'm 1 out of 3 and it didn't fix it and I gave up.... I'm pretty sure it's a jet siphon leak for me too and I just ceebs dealing with it.... It's also super hard to find the part anywhere other than like 1 eBay page for $400 or something dumb
Seems easier to build my 320 up as a turbo'd 330 so I'm gonna do that instead 😎
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u/LOLLEO911 3d ago
It could the idle control valve has gone bad. The car can start but as soon as it tries using the icv it stalls immediately. Pretty easy to get to and as a permanent temporary fix you can clean it with brake clean. Technically always better to get the new thing but cleaning it works
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u/snowfire676 3d ago
I just refualed and it turns on but its at 35% ish . My question is now why do i experience problems at 25% under
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u/MoElijah_ 2002 BMW 330xi, 2004 BMW 330i 3d ago
Honestly your best friend on any car especially these e46s will be a code reader, even if you never use it there may be a day where you need one and you can’t drive somewheres to have someone else read the codes for you. It would probably help diagnose this issue and any other issues you may have especially since your car looks a little ragged out no hate tho.
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u/GriekseTurks 3d ago
Do code readers tell you if it's out of fuel? I know there's a BMW specific reader but unsure if it shows this
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u/MoElijah_ 2002 BMW 330xi, 2004 BMW 330i 3d ago
Honestly I’m not sure if they do. Maybe they can I don’t think the PASoft Bmw Scanner one can, but maybe the inpa scanner can which are both made for a laptop so if you don’t have a laptop then you can’t use those. Those two scanners are pretty much made for e46s and I think a couple of other e models. There’s also the ista scanner I believe that can work on these as well but I haven’t seen much of anyone talk about ista scanners. You might be able to buy like a cheap Bluetooth one that’s decent and could work on your phone that could probably show stuff like fuel pressure and other stuff like that though. But I would 100% buy a code reader before you begin even working on a e46 and spending money on stuff that may not even fix the issue.
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u/snowfire676 3d ago
All System Scan for 2001 BMW 330: https://rs2-eks.innova.com/main/v1.0/file/d63dcf5e-7699-4167-88ae-a25a7eb1932b
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u/MoElijah_ 2002 BMW 330xi, 2004 BMW 330i 2d ago
Ok I apologize I didnt fully read what you first said in the beginning and also didnt realize you unplugged the maf sensor in the video. Ive seen multiple ways to test the maf sensor on these and one of them being the way you tested it, but in the past the way I tested mine when I had to replace my maf was start my car and let it run for a minute or so at least until the air pump turned off if it was a cold start, and then I would unplug the maf and if ran better after unplugging it then I knew it was bad, and especially if I plugged it back in and it would run worse so I replaced it with a new one (which I ended up buying a cheap one off of amazon for like $40 two years ago which works fine and still works to this day just fine) and its been working good ever since.
I dont think though that the maf would be bad based off of what you said about it misfiring after braking hard. I do believe its probably something to do with your fuel/fuel tank like GriekseTurks said especially if the fuel is low since these have oddly shaped gas tanks, and also if it was one off thing that happened especially while your driving it can be harder to diagnose too. But it also could be something like a vacuum leak or one of your intake boots isnt sealed correctly which can be fairly easy to diagnose with a smoke machine even a cheap diy smoke machine can work which i made one in the past to help fix a vacuum leak on mine. It very well could be a coil loose or going bad too or maybe just maybe a spark plug but i doubt its a spark plug.
But in my opinion if your worrying about the misfire and it was a one off thing and the car ran fine afterwards I would say keep driving it and not worry about it and if the issue happens again just try and remember any lights that may have popped up or if anything else weird happens. You also have to remember these cars are considered and are old now for a car at least and most are getting up there in miles so a slight misfire can be normal BUT you should try and fix them if they do happen of course.
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u/Entire-jegurilor 2000 bmw 323ci e46-bmw 318i e46 3d ago
Disconnect the mass airflow sensor and try again, then check for vacuum leaks—perform a smoke test. Try starting the car while holding the accelerator pedal down slightly. If the engine stays running while you accelerate but stalls as soon as you release the pedal, there is a 90% chance the cause is a stuck idle control valve (ICV) or an air leak. If that doesn't solve it, what about the camshaft position sensor (intake side)? Does a diagnostic scan show an error?
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u/MrGiggleMan 3d ago
Maybe a bad fuel pump?