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Cylinder 2 Misfire help N62B44
I'm trying to increase my knowledge on cars (especially BMWs) and learn how to diagnose and fix problems.
my cylinder 2 has a misfire (N62B44) it usually happens when the engine is cold and then goes away when the engine warms up and clear the code I already swapped the ignition coils and the spark plugs and so far cylinder 2 is still misfiring Can someone give me a list of things to diagnose or check? we think it could be the ECU because we replaced it a while ago which was not needed because it had a previous timing issue, the people who changed the ECU didn't seem so good at what they were doing and we think the ECU is bad. I have an advanced Foxwell scanner that can go into details and read everything but the problem is my dumbass OBD2 port also does not work which we also think is from the ECU. so I'm kind of stuck in a bull shit situation the car also has a previous idle misfire without any code or SES popping up, but this one is different because you can literally feel it when you accelerate and SES turns on after giving some gas by the way, I drive the car pretty hard (I have a heavy foot) |
Wasn't on BMW but was on a Ford truck but very similar issue ended up being cpk (crank position sensor).
How the hell it was always either cylinder one or five the world will never know but there you have it. My guess is cpk or wiring (including wires inside the DME or the connector to it). Clean the DME connectors |
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How big is your tool box?
You can move the fuel injector to another location. Better yet, ohm each injector. Check for ohm differences. You can use a special tool to monitor fuel injection pulse. I have a Power Probe IV with a pulse feature. The injector could be leaking too. How many miles are on it? Worst case, the head gasket may be starting to fail. Do you have a mysterious coolant loss? Check compression on a hot cylinder. Is the coil a good brand? Why type of spark plugs are you running? |
I missed that injectors weren't part of the test equation yet. When i was chasing a random misfire on wife's car i ran Lucas injector cleaner and it was cured. If you haven't run injector cleaner through that'd be the next thing to try also swap inevitable l injector location.
(We swapped injectors on the f150 before the crank sensor error stayed on cyl 1) |
Dads basically a mechanic so the toolbox is big, we might take it to someone so they can check it out, the car has around 130,000 Miles on it, I do have random coolant loss but the coolant system has had problems before and we think one of the aftermarket parts don't seal well which cause a leak. I would rather not touch the fuel injectors YET but we have put injector cleaner and octane booster which did not fix anything, also could the fuel injectors have anything to do with Misfire when cold but works fine hot? I mean the car pulls when I give it gas on the freeway. also, can I just check compression the traditional way or is it different on these engines? What's a good PSI for N62? coils are mixed bosch and some aftermarket ones (cylinder 2 is bosch) spark plugs I do not know but I also swapped them and it's still misfiring the same cylinder. I do hear weird sounds when my windows are down and idle next to a car (sound bouncing off other cars) i don't wanna cheap out but I would like to save money because this car has other problems that need to be fixed.
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All you need to know about the N62 engine: https://www.internetsomething.com/lp...2%20Engine.pdf
What other codes are present? A bad misfire will also show up as bad O2 readings. Common ones are P0420 and P0430. A normal compression tool will work. Inspect the coil electrical connection. What year is it? Did the N62 go through coil lock down connections too? |
Deoxit on the DME connector can resolve mystery signal caused errors.
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Cylinder 2 Misfire help N[emoji239[emoji2392]]2B[emoji2392][emoji2392]
ECU under the hood. When I first got my first x5, i had random errors that m were cleared up when i cleaned and treated the 4-5 connectors to the DME.
Deoxit pro gold can't be beat. |
haven't tried cleaning the ECU but I did a compression test all of the cylinders passenger side were about 120 Psi, opened the valve cover and checked the springs and everything looked good too, what could be next? also the idle misfire has gotten really bad the whole car shakes. I doubt it's the fuel injectors but I might have to check those next
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The DME is not under the dash.
Have you checked the eccentric cam gears? If the valve covers were off it should be easy to check those. Excessive wear on those can cause problems similar to what you are describing. |
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I haven't done much with valvetronic but if the mis is only at idle I think wear in the valvetronic linkage is highly suspect. Maybe try bumping up the idle speed.
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Idle speed can not easily be adjusted.
To check the eccentric cam gears you only need to remove the valvetronic motors. I would check both sides since you only removed one valve cover before. You can't say the engine is healthy if you only checked one bank. Saying the engine has been slightly "rebuilt" is actually cause for concern for me, to be honest. Most people don't know how to rebuilt the N62 correctly. I would |
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In the spirit of doing the easy stuff before the hard and expensive stuff, You may want to check all your grounds. Especially the ones under the coil covers. Though the fact that your OBD port isn’t working seems to point to the DME perhaps…at least in my one brain cell. Can you access other modules, like the transmission module? My single cylinder misfire turned out to be water intrusion into the actual harness during a coolant pipe job I did. |
Alright imma take your advice probably around Thanksgiving break I can focus on my car.
Does anyone know why it's usually whenever the car is cold? for example, it only happens in drive from what I've experienced usually when you gas it a little bit but not suddenly. I try to replicate it in Park but no misfire, but in Drive, if the car does not warm up for a good minute or two (by that I mean past the cold start cycle, I hold revs at 1k then 2k then 3k then 4k till my coolant is close to the middle) it'll give me the error. I usually just drive with my OBD2 connected and delete it till it goes away. once my car is warm and the code has been cleared once or twice it runs great and pulls through traffic with no problem until I come to a stop and idle then I meet another misfire which literally moves the whole car (I think this is a completely different misfire) I'm going to look for my old ECU hopefully I can find it so wish me luck. |
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the guy who rebuilt it pointed at multiple "problems" till we found out something in the valvetrain went wrong (I forgot what, it was a spring or something) he even made us change our ECU which was not needed from what I know. |
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Follow Up (Motor Apart)
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Alright, it's been a minute since I've followed up with this forum, but I recently graduated and have time to myself.
We took apart the intake manifold and valve cover, and I got some pictures to show. You can easily tell that the cylinder 2 exhaust port has a lot of carbon buildup, which I'm assuming is a case of bad spark, because if it were a case of too much gas, it would be cleaner, no? Anyway, we checked the springs and eccentric gear (the one in the picture, right?), and everything seems fine; regardless, we're replacing everything if I'm not wrong. my guess is the ECU is a shit one because before someone told my dad that it wasn't working well (his wording not mine) so we got one from LQK Pick Your Part and its ready to be coded and installed. I could be wrong, but I feel like it could also be the eccentric gear sensor, but the OBD2 port doesn't even work for me to monitor with my Foxwell scanner. We also might replace the valvetronic solenoid thingy if we have a spare one, which I'm sure we do. I'm currently posting this because the engine is still apart, so if anyone has a clue for what to check for, I assumed that now is the time before we put everything back together. We're gonna do a leak-down test soon to see if any of the valves are messed up. im also gonna try to convince my dad to just completely replace the injectors and ignition coils because the ignition coils are mix and match of bosch and some aftermarket chinese piece of shit coils which literally broke apart as we were pulling it out. (cylinder 2 is bosch i already thought of that beforehand) To those who said to clean the ECU, I did that, but with rubbing alcohol. Nothing changed, cleaned the ports too. I hope the pictures I provided are good, but I can take some more before we put the motor back together. Sorry if the pictures are too big, I didn't know what resolution to resize them to. |
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If it gets power but zero connection with the car try letting it decode your ViN itself. A wrong ViN can (sometimes) make it look for modules, etc that aren't there and stop it from going farther. Sent from Embassy network using Tapatalk |
I have another scanner which does power on, but it does not connect first try, so I have to plug and unplug till it connects to KWP2000, then yeah, it reads most things, but it's a generic OBD scanner.
The Foxwell used to work perfectly before, and it got the VIN correctly automatically. The thing is that my Foxwell broke once, and I have a suspicion the X5 shorted it or messed something up. I already used my warranty, so I don't want to risk it, know I'm paranoid, but the scanner wasn't cheap and was a gift for my dad. :dunno: I have yet to check the pins, but if the other scanner connects, should I even bother? Regardless were most likely changing the ECU. |
I can't believe the Foxwell got nuked, they are tough. Mine has been through hell plus I keep mine in the door side pocket and the temperature here has gotten to 60c.
Keep trying and if it connects run the auto scan and then do a quick clear, rerun it one time more then do live data on any repeats or unclearable items. Sent from Embassy network using Tapatalk |
Yeah, I also got surprised paid around $250, and it just stopped working one day. emailed them, they said they can send me a new one, but I gotta send the old one back, and I use my warranty. I did what they said and this one works fine, but im not sure if I wanna plug it back into the X5 because now I don't have a warranty. not even sure if the X5 is the cause.
But yeah, I'll see what happens. I wanna check the live data to see what's going on. |
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If the problem is only at idle and you ruled out everything else it's likely that a valve is not opening enough, (especially with that engine asfaik) so that is what you should be looking at, and for something that would cause that, especially now with the engine apart.
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test your Foxwell on another OBD port, or with extra supplied power
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Another thing, if the supplied voltage on your BMW's OBD port is too low, then the Foxwell might act up...my NT510 Elite really doesn't like low voltage (under 12.2v), so I never use mine unless I'm running the engine, or have a charger/maintainer hooked up. I prefer using my Solar/Pro Logix 2320 (20 amp) that has a "stable power supply" feature, that maintains a constant 20 amps so my Foxwell never acts up, anymore. Of course, the 20 amps wouldn't be enough for coding later model X's, with more modules than my early E53, but I won't be coding anyway. |
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We're going to do a leak-down test to see so ill fill you guys in on what happens. Quote:
The Original Foxwell I got worked fine, it even had the BMW software, then one day it just stopped working, not just on the X5 but on whatever car I tried it on. Foxwell did some remote access stuff, and they considered the scanner faulty. We now just use a generic OBD2 scanner, but that still has some problems mentioned earlier. Quote:
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A misfire only under load is usually a spark problem.
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The DME shuts off fuel pretty quick to a missing cylinder.
I'm not going to reread this thread but you seem to be a bit all over the map about what's going on. Did you do a compression test ? Do you have a scan tool working? |
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leak down test is next once the kit comes. |
Not likely that all cylinders were within a few psi of 120. Did you do only 4 compression strokes or 10 or whatever seconds of cranking ??
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We did 5 cranks and they all came out fine, no sudden loss of pressure or anything like that. Regardless, we're still gonna do the leak down test to be more precise because we could've missed something. Until then, I don't have much to say until I get the results, gotta go pick up the compressor from the shop. |
well uhh i think we found the problem, we took off the rockers and stuff so the valves stay closed, put some air into the spark plug hole and gasoline in the exhaust port and it started bubbling like crazy.
we have a bent valve, here's the video https://youtube.com/shorts/yhOJENiTfrU I tried to upload it as a normal video but it became a short ): so basically the dude who did our timing guides messed up our engine and didn't tell us. so from now on were probably gonna stick to working on our own cars. |
You forgot to say "Thanks for all the help from the this forum."
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