Trouble with spark plugs socket size

[t3hricardo]

Hi guys!

I hope I can find a bit of guidance here. I have BMW e46 318i year 2000. Was about to change spark plugs. got 3 out without any issues with size 16 socket, but for god`s sake socket does not fit last spark plug. It is a bit odd as I would think that whoever was changing sparks before me, he would change them all at not just one or three.... I did order universal spark remover from ebay for couple of dollars that fits 16mm/21mm but that one is too big for space avaliable around spark plug. Car is used, god knows which owner am I. So the question is, what size of spark plug can it possibly be? smaller then 16mm or bigger?or can you fit in thin wall 21mm? I dont have many tools here with me and buying sockets few sizes up and few sizes down from 16mm seems waste of money to me. Maybe someone experienced same issue as me and will shed some light.

PS: I tried to google socket sizes of spark plugs that are standard and obviously that is 16 & 21 mm. Could I have something attypical in there?

Many thanks,
Richard

[t3hricardo]

I just found that BMW is using 14mm too. I think I try that

[dworthy]

Welcome to the Forum!

For that car it is suppose to be a 16mm sockets. However if somebody got their hands on a newer style, improper sparkplug, it would require a 12 point 14mm special socket.

[ross1]

Check to see if the rubber insert from another socket hasn't been left on your spark plug when last changed.

[t3hricardo]

thanks, checked that, nothing left there. will wait for 14mm socket and see if i can take it out. either way, I give you update .

[MarcoZandrini]

Just checking to make sure you’re installing NKG BKR6EQUP plugs. These are the only plugs that go in the M54 engine.

[dworthy]

Just checking to make sure you’re installing NKG BKR6EQUP plugs. These are the only plugs that go in the M54 engine.

Ahem, he has a M-43TU motor, but it uses the same spark plugs.

[bmwdirtracer]

Look carefully into the hole. Is this a 6-point or 12-point "nut" on the sparkplug ? If it's six point, it's going to be 16mm. If its 12 point, it's the special thinwall 14mm socket.

I thought I recalled using a different adapter when compression testing a n engine with 14mm sparkplugs, so I'm guessing that someone has just screwed up the hex on a regular 16mm plug, or there's something preventing the socket from engaging the hex. Try blasting compressed air down into the hole, see if any rubbish flies out.

[MarcoZandrini]

RTFP! Argh! Thanks Darin!

[t3hricardo]

IMG_1925.jpg

[t3hricardo]

this is the best picture I could get, it is 4th spark plug so worst access of them all. It looks like 6 point nut from what I can see. Still waiting for 14mm to be delivered. Regards sparks plugs that I am going to use, they are some cheap ones from ebay saying it fits m-43TU engines. They are one pin cooper body spark plugs. I know what most of you will think, that I should not save $$ etc. but I only use car to go beach and back. I make roughly 3-4k a year at the moment and car is frankly old so dont feel like putting too much money in it. And my understanding is that cooper ones disadvantage is their lifespan and not much else, or do you not share same opinion? if not, I would be happy to hear you out since I am just layman mechanic . In a mean time I have just changed oil filter housing gasket + o-rings, fun job you guys. Dismounting all the staff to get to one tiny gasket.

[bmwdirtracer]

Sorry, but only the correct spark plugs are the correct spark plugs. Just because something "fits" doesn't mean it will work correctly.

Buying incorrect, "cheap" parts for your car is a terrible waste of money and time.

What if the spark plugs you replaced had been bad...and the new , incorrect spark plugs are the wrong heat range, or the wrong length, or incorrect in some other crucial spec, and they don't fire correctly, reliably, either ?

Then you'd be thinking that your poor-running engine has a DIFFERENT problem, because it clearly wasn't the plugs, because you replaced them already.

Now, you're going to spend lots of money and time chasing a problem that should have been fixed, if you'd have just bought the correct parts. You need to buy the correct spark plugs: NGK BKR6 EQUP, also known as NGK part number 3199.

[ross1]

So?

[t3hricardo]

Hi guys! Finally I mannaged to get spark plug out. There was bloddy piece of black plastic stuck between hex and engine block which I could not see first time. So all 4 plugs were same. Yet my problem has not been resolved so again I ask again for a bit of guidance. I found out that number 3 spark plug cable is not giving juice. Never came across this issue before so I do not have an idea where to start. What to check first and how to identify which part needs replacement. Thanks a lot for all suggestions!

Regards,
Richard

[t3hricardo]

could it be just simple swap of ignition coil or should I dig deeper ?

[bmwdirtracer]

If the wire isn't shorted out (grounded on a piece of metal), you need a new coil pack, or the engine computer is bad, or the wires from the engine computer to the coil pack are bad.

The odds are GREATLY in favor of the coil pack being bad.

[dworthy]

+1

You are going to need a multi-meter to test this system.

So set it to Ohms, and do the following with the probes:
1) 1 (-) and 2 (+) .4-.8 ohms
2) 6 (-) and 2 (+) .4-.8 ohms
3) 7 (-) and 2 (+) .4-.8 ohms
4) 5 (-) and 2 (+) .4-.8 ohms

This will tell if the windings inside the coil are bad. Now if anything falls outside of those parameters, you will need a new coil pack. Also test each plug wire for breaks, cracks ect. You can also use a multi-meter to check the resistance of the wires.

@Chris, the M43TU uses the same engine electronics as the M-44 motor.

[t3hricardo]

thanks guys, I will try to figure it out. Will update you. Appreciate all ur help.

[t3hricardo]

Ok here we go. I unfortunatelly dont have multimeter, so I tried to swap leads. originally I thought that lead n.3 is bad, so I swapped it with n.4. Now lead n.3 is giving spark when pluged in n.4 slot & lead n.4 plugged in n.3 slot is not giving spark. I guess then ignition coil is faulty in n.3 slot? Am I thinking right or am I missing something?

[bmwdirtracer]

You have ruled out a bad wire. Again, it is possible that the engine computer has a burned out coil driver, or the trigger wire from the computer to that cylinder's coil is bad, but the probability is about 95% that the coil pack is bad. Just so you know, you can buy a cheap multimeter for about $25.

[ross1]

Or swap coils and see if the miss follows the coil

[dworthy]

Or swap coils and see if the miss follows the coil

M-43TU motor doesn't have individual coils, only a coil pack like the M42/44 motors. It wasn't until the N-4x motors did BMW state to use individual coils for the 4-cylinder motors.

[t3hricardo]

Hi guys, an update for the once who are interested - finally received coil pack ( used one) , put it in and car is running on 4 cylinders again and with new spark plugs along, it feels to be more alive then before. Thank you for all your help and support! It is great that in this age , you can still find people that are willing to help others out. Thanks again!

Richard

[dworthy]

Thank-you for coming back to let us know it was fixed, and of course what it took.

Happy driving, as the E-46 is a good car to have.