Do I have the wrong spark plugs in the engine?

Hi Wayne,

Great article as always! I just bought a 1995 325is and have been running through all the routine maintenance I can think of since I don't have any service records.

After putting in brand new Bosch plugs, the engine was hard to turn over. When it did eventually catch, it had a hard time even running. Gradually it did improve and was better after shutting it off and starting it up again.

Ever since, cold starts lead to a rough idle and it seems to be missing sometimes. What would be the first place to start? I did notice there was only one grounding strap on the engine M50TU. Is this normal?

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This post was auto-generated based upon a question asked on our tech article page here: Pelican Technical Article: BMW 3-Series E36 Spark Plug Replacement

[Wayne 962]

You might have the wrong spark plugs in the engine. Spark plugs are rated at gap size and heat range - if they are not correct for your car, then you may have problems like the ones that you are experiencing right now. If you have the old plugs, you might want to reinstall them just to check.

- Wayne

[Manolito]

This car came originally with Bosch two-electrode plugs F7LDCR, F7LTCR, or FR7LDC. Bosch now has an updated part number (I don't have handy) but it will say that it replaces the above. Should cost about $2.50 ea

Several of us have tried four-electrode plugs in e36s and found that they are equivalent or perhaps not quite as good. Certainly not worth paying more for.

BMW has switched to NGK plugs, at least in the models with which I am familiar. I personally use either Denso or NGK in all my vehicles. Bosch may be OK, but if the box says it was made in India or China, I would avoid it.

Since your problems started with a plug change, I would double-check the ground straps to the coils and make sure they did not get damaged.