I think this 325xi has 130k on the original plugs

[nonturbodan]

I'm catching this one up on a great deal of overdue maintenance and its running well other than a moderately rough idle. Not like a dead cylinder just evenly rough. Its not picking up misfires after clearing codes but it did have faults stored for misfires on 2-6.

Pulled the plugs out to find not much left. I will get pics. I don't know if that's a record but it is impressive, 130k on stock Bosch plugs, the ones with the small diameter electrode. Its burned off to about .5mm down into the insulator

I have some NGK BKR6EQUP's going in there, which I hope solves the rough idle. Everything else is good. I just repaired the DISA, replaced the CCV and hoses, intake boots and rubber hoses while I was in there. Runs great except for when it settles down to idle speed. Ordinarily you can't tell the engine is running at idle, this thing feels like a Honda. Not good.

[charter21p5]

I'm catching this one up on a great deal of overdue maintenance and its running well other than a moderately rough idle. Not like a dead cylinder just evenly rough. Its not picking up misfires after clearing codes but it did have faults stored for misfires on 2-6.

Pulled the plugs out to find not much left. I will get pics. I don't know if that's a record but it is impressive, 130k on stock Bosch plugs, the ones with the small diameter electrode. Its burned off to about .5mm down into the insulator

I have some NGK BKR6EQUP's going in there, which I hope solves the rough idle. Everything else is good. I just repaired the DISA, replaced the CCV and hoses, intake boots and rubber hoses while I was in there. Runs great except for when it settles down to idle speed. Ordinarily you can't tell the engine is running at idle, this thing feels like a Honda. Not good.

Install the NGK platinum plugs. They last ~20k miles. You should notice a difference.

[MIKYZZ4]

Let me guess, you've had a CEL for over 50,000mi. and another thing I find impressive is, that your cat converter hasn't failed.

[randy72877]

Replace the coil boots also. This is necessary for the age. They are cheap and easy to replace.

Sent from my SAMSUNG-SM-G870A using Tapatalk

[nonturbodan]

Let me guess, you've had a CEL for over 50,000mi. and another thing I find impressive is, that your cat converter hasn't failed.

Not my car. A coworker just purchased it and we are going through a great deal of neglected maintenance.

New NGK BKR6EQUP plugs made no difference in the idle. Runs great off idle, but as soon as RPM settles back to idle it dips slightly below where it should and runs rough. I had the guy drive the car a bit and the check engine light did come back on. I'll have to read the codes and see what its coming up with.

The car runs great other than the idle issue. Very smooth and plenty of power.

[nonturbodan]

Replace the coil boots also. This is necessary for the age. They are cheap and easy to replace.

Sent from my SAMSUNG-SM-G870A using Tapatalk

This M54 has the pencil type coils with the integrated boots. They seem to be alright though. No misfiring under load. Only a rough idle which I suspect at this point is air/fuel related.

[MIKYZZ4]

Check for intake leaks.

[MarcoZandrini]

OP, the first thing you bud needs to do is to load the OBDFusion app on his smartfone. It comes in both iOS and andriod flavors. The iOS needs a wifi adapter, while the android uses bluetooth as an interface. The interface adapter sits in the OBD2 port under the dash. Buy a VeePeek interface adapter from Amazon. That brand seems to be the best adapter available. Go to E46Fanatics and search for threads on OBDFusion that have comments by user "jfoj." He's the resident guru on OBDFusion. Also, have the intake smoke checked to find all of the leaks.

The NGK plugs are good for at least 50k miles, and not 20k as someone wrote.


what year is the car? Early cars (MY 1999-2002) have separate coils and boots, while later MY cars have an integrated coil and boot. If the car is an early MY, then definitely replace the boots.

[nonturbodan]

This is a 2004 xi. I have a scan tool that I'm using for diag. I can monitor adaptations, stream oxygen sensor readings, pretty much everything.

I got back in there last night. Replaced a bunch of vacuum lines that were the consistency of fresh play doh. Replaced a few vacuum caps that were split. The big thing turned out to be the oil filler cap. Whoever put it on didn't get it right and it was halfway out on one side. Might have been me. We do drink while we work on this thing.

Now it runs smooth, idle adaptation is under 1%, precat oxygen sensors are .3-.7V at idle. Now I will continue on to replacing the two regulators I haven't done yet, both front axles, tie rod boots and front brakes. Already did the cooling system and the other stuff I mentioned.

[dworthy]

Actually the NKG plugs should last 100k, as reported in the SIB attached.

[FFMan]

i thought first plug change on service interval was 80k miles on a 325. Mines at 77k miles and i have a set waiting to go in at next oil service.

[nonturbodan]

It should be done at the inspection 2 service if I remember correctly. Lots of other brands run similar long life plugs until 100-110k miles though.

[dworthy]

i thought first plug change on service interval was 80k miles on a 325. Mines at 77k miles and i have a set waiting to go in at next oil service.

Well according to the service sheet, it should be 100k for plugs and 120k for oxygen sensors, unless you have the SULEV which is 150k.

It should be done at the inspection 2 service if I remember correctly. Lots of other brands run similar long life plugs until 100-110k miles though.

The Inspection 2 applies to the older BMW's and the newer M-models, but I have know guys to change them earlier, it's your car and money.


For you I have included the service sheet so you can see what I am talking about.

[nonturbodan]

And there we have it