Hello, My 2001 325i was making a rumbling noise, sounded like an old boat, but other than that it ran fine, thenI let it sit a few days, then it wouldn't start. I read the CEL and had a misfire on cyl 1&3, so I got new spark plugs and ignition coils for the two misfiring cylinders. I also replaced the fuel pump and battery, but after that it still wouldn't start. I am waiting for my new fuel filter to get here, I thought that would be a good part to update with the fuel pump replacement. Is there anything else I can try? Even after the fuel pump gets here, I still think I'll have some work to do. Any advice is appreciated
Does the vehicle crank over but just won't fire off? The way to check if it needs a fuel pump is to remove the fuel rail cover and crank the engine over a couple of times. There should be on the fuel rail a shrater valve on there take a small screw driver and press on the valve fuel should shoot out under pressure if it doesn't then you know you have a fuel pressure problem. And you will need to check power supply to the fuel pump while cranking the engine. If the fuel does shoot out then you probably have another issue.
yes after I did the fuel pump, fuel did shoot out the schraeder valve, but it still wouldn't fire. Is there anything else I can try?
Check if the coils & fuel injectors are getting power/firing signal? I'm not so familiar w/ E46, but presumably the ecu controls that, I'm wondering about signals on the input side to the ecu that might cut the spark or injectors if some sensor is dysfunctional and not outputting whatever voltage/signal the ecu expects.
The reason I changed the fuel pump is because of the grumbling noise it was making, I saw some youtube videos of people with the same problem, and that seemed to fix it. I did the spark plugs because they were overdue and the coils because of the misfires. How can I check if the coils & fuel injector are getting power? thanks for the help
Easiest way to see if the coils are firing is to remove the spark plugs and install them into the coils and ground the spark plugs and have some one crank the engine over and see if there are no sparks on all the coils then you have a issue with coils being enabled from the DME (motor control unit). If you do get sparks then you should be able to see fuel on spark plugs if the injectors are firing. Do you have another key try starting it with that to make sure the rolling code is working.
Ok, I'll check the spark soon and report back. Trying the other key didn't work, but thanks again for the advice
The plugs aren't wet, they haven't been used to start an engine yet, brand new. Do you know anything about blown fuses?
I am getting 2 dead fuses on the black box labeled MOTOR-SICHERUGEN they are the first and last 30a fuses. Does anyone know what they control?
theres no label under the lid, but I found this online: http://www.chitownm.com/forums/showthread.php?t=4284 I know the diagram looks like its from an M car, but I'm looking in my Bentley manual and for fuse carrier A8680, it only shows 4 fuses. Again its both 30a fuses on the ends of the unit labeled motor-sicherungen
Bavauto calls it the engine electronics fuse pack - http://blog.bavauto.com/5677/bmw-e46-3-series-engine-electronics-fuse-pack-in-underhood-e-box/ A general post - http://forum.e46fanatics.com/showthread.php?t=1011677 Using Charlson's method for checking the plugs, you know you're getting power to and thru the coils and to and through the plugs. With the plugs installed and the fuel system pressurized up to the fuel injectors (meaning the fuel pumps work and are getting a signal to run, and no fuel line blockage/plugged, thus there's fuel to the fuel injector rail), AND the fuel injectors are getting a signal to trigger open, then, when you try to start the engine, it should at least try to run. Engine needs air to run of course, but that's the least likely problem area if the car was just running. If, after cranking the engine over with no start and you pull a plug and find it dry, that would show gas isn't getting to the combustion chamber - so... likely candidate at that point, I'm guessing (Charlson may have more enlightened suggestions), is something related to the injectors. If the diagram you found is accurate for your car (wouldn't be surprised if it is), then blowing fuses 1 & 5, it says both are tied to the injectors. Charlson would have an idea about what might cause those to blow (some sort of short?). I don't know whether a bad fuel injector relay could cause those fuses to blow, but, that would be relatively simple to swap out and try. If Bentley has wiring diagrams for the fuel system, then you can at least on paper trace thru potential culprits. Sudden DME failure would seem unlikely to me (although not impossible), I'd think it's more likely something else. On E30's, the crank position sensor is a critical input, if the ecu doesn't get that signal, then, no start; memory is a little fuzzy, but I think on E30 it wouldn't either run the fuel pumps or trigger the injectors. E46 much later car with totally different engine, I don't know if it has the equivalent of an E30 crank position sensor somewhere in the wiring, electronics, etc. From google translate, sicherugen = fuses, so literally it just means 'motor fuses'
Ok so number 5 goes to the fuel injector relay. Number 4 it looks like its for oxygen sensors heating. When dealing with blown fuses best to start and see if it is a dead short by putting two new fuses in and seeing if they pop right away if they then you will need to find out the short which could be wiring, a component such as a oxygen sensor or fuel injector maybe even the relay itself. Have your checked to see if you have power at the injectors with the key on (if I remember correctly these are controlled on the ground side by the DME)?
Thanks for your help. This is above my skill level. I'm gonna get it towed and fixed at a shop. I'll just have to chalk up the repairs I made as "preventative maintenance" Thanks to everyone
The Bavauto blog link I posted before shows how to remove the fuse pack and remove its cover to change fuses, might be worth trying that and swapping in a fuel relay for one more shot before sending it off to a shop. Access is easy since you've already pulled the cover, fuses are cheap, checking Bavauto, not sure which relay is the right one, but the most expensive isn't too bad, ($18.00), then $11.00, & $6.00. You need a voltmeter to check if fuel injectors are getting power. If you try new fuses and a relay and the fuses blow trying to start the car, then leave the short-tracing to a shop. Winter just got here in Ohio, so if you're someplace freezing & working outside, I can understand not wanting to futz with it further.
