Misfire under acceleration (I think)

[Termite]

Hi,

My first post on here. I bought a 1992 J Reg 320i SE, with 78k on the clock and has full BMW service history and was last serviced a couple of thousand miles ago. Apparently it's been sitting around a bit and olny done 1,000 miles or so since it's MOT in august last year.

When taking it for a test drive, I noticed that the car is hesitant like it's misfiring at 2-3,000 revs. Sometimes there's a small backfire, but no big bang. Once past this it seems to be fine, although maybe not pulling as it should. Other than this the car is superb and much better that my rattley old 318i with 168k on the clock! So I bought it as it was cheap from a mate of mine who is a dealer.

Has anyone got any idea what I should check first? I've had a search for misfires and seen a few things about the spark plug coils. Is this a good thing to change first? Does the problem sound similar to anyone elses?

Thanks.

[Conehead]

My suggestion would be the trifector....plugs, fuel filter and air filter to start with...they are the easiest and cheapest to start with.

If you do change your plugs, get the IRIDIUM plgs from NGK.

If its been sitting for awhile, just replace the stuff, no matter how many miles its done from the last service.

[jasonf860]

+1

[Termite]

Cool. Think I'll take it out for a drive today, maybe down a bit of dual carriageway to open it up a bit and clear any crap out, then change the rest sometime this week.

Worth an pil change as well do you reackon? It's last service as an oil service and when I dipped it, it was nice fresh oil.

[Conehead]

Wouldnt hurt mate.....filter as well

[Pirate_copy]

Run some fuel system clean through too mate

[Termite]

Fingers crossed that'll sort it then and it's not a O2 sensor job. :)


Cheers.

[Pirate_copy]

O2 and camshaft sensors are the place to look AFTER the above buddy.

Could also check the intake boot for damage and the clips are tight

[Bmwracer]

Mine missed fired for a while until i changed the Coils soo try that too but they are pretty $$$$

[Termite]

How much are the coils roughly when you bought them? I'm in the UK, but just want a general idea.

[Pirate_copy]

About £30 each mate (£180)

https://secure.gsfcarparts.com/shop/index.asp

[Termite]

Thanks for finding that. Let's hope I don't need then then!

[Pirate_copy]

Luckily, there are other (cheaper) things to check first buddy

[Termite]

Quick update.....

Took it for a drive today to open it up a bit in case there was any crap in the system. It was still doing it. Popped the hood and there was a intermitant clicking sound coming from the top of the engine. Took the engine cover off and started it up and noticed one of the coils was arcing.

Swapped that coil over to a different position to make sure it was the coil and sure enough the coil was arcing again. Took it off to inspect it and noticed a tiny pin hole in the platic casing where the moulding was obviously faulty.

Stuck a blob of slicon sealant on it to cover the hole and the car is running fine now. :D Will obviously change the coil at somepoint soon, but will see how it runs for the next week or so.

So thanks for all your help guys. First time I've been on here and the replies were most helpful. :)

[Conehead]

Glad to hear.