Cylinder 2 Misfire help N62B44

[Fatcat]

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)

[andrewwynn]

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

[Fatcat]

Originally Posted by andrewwynn

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

I was honestly thinking the same thing (crankshaft position sensor) I swear if it's that then I got some sixth sense or something, can you elaborate on the wiring and where it's located?

[X5chemist]

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?

[andrewwynn]

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)

[Fatcat]

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.

[X5chemist]

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?

[andrewwynn]

Deoxit on the DME connector can resolve mystery signal caused errors.

[Fatcat]

Originally Posted by X5chemist

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?

currently only misfire on cylinder 2 but before on my more advanced scanner there was a random misfire and a misfire on cylinder 7 but I think we fixed that by swapping coils if I'm not wrong, by coil electrical connection you just mean if it fits good right? its a 2004 4.4, what do you mean by if it went through coil lock down connections? i honestly don't feel like doing a compression test because I gotta take out all the spark plugs but I don't think I have any other choice right now

[Fatcat]

Originally Posted by andrewwynn

Deoxit on the DME connector can resolve mystery signal caused errors.

DME connector is the port where the OBD scanner goes in right? or is it a part of the ECU?