Mysterious Miss Fire

[estee]

Hi All

I've got a missfire, M401992, its been into the stealers they've no idea what it is without "decoking the engine" which will cost over a grand.

SparksHT all changed, dizzy cap changed, injectors check, ecu checked, ignition system checked.

I'm at a loss, my mates got it at the moment in Armadale, he's not got back to me so I'm not holding out much hope.....sounds like a transplant job 1!

Anyone any ideas...damn those M40's

[Bob_S]

decoking the engine to me sounds like thrashing the bollocks off it lol!

could be clogged injectors mate! or fuel starvation?

[estee]

decoking the engine to me sounds like thrashing the bollocks off it lol!

could be clogged injectors mate! or fuel starvation?

LOL , first thing I thought of was Kate Moss in rehab...

Tried the injectors, but the fuel theory sounds interesting, it seems to run better when its really low on fuel

[Templ8e30]

If it runs better when low on juice it could be the fuel pressure regulator at fault ?. Iirc the 318i uses a 3 bar regulator same as the 325i.

Have you tried swapping the ignition coil with another one ?, I fitted a brand new performance coil from demon tweeks last week and it was fine at idle but refused to rev over 3k because of massive missfire under load. The whole car was shaking at one point so I sent it back.

Have you had a compression check done ? might be a sticking valve or a broken piston ring.

Cheers,

Iain T

[gazza]

my m40 rattled at the top end and had a really anoying missfire when cold changed everything as you have ....didnt sort it ..then i changed the cam/rockers/tappets to quieten it down they were well worn .....missfire went ...i believe wear on the camshaft/rockers was not allowing one of the valves to open/close correctly giving me my problems

[Dan318-is]

i to have a misfire bu only at high revs in second and third occasionally , on an m42, an iv had compression test too

does your missfire occur all the time?

[estee]

Hi Awl...I know its been along time but my mechanic has been waiting for an auto electrician to take a look at my car before he did any other work.

He still cant find the problem, he says he check everything possible without removing any engine bits !!!

The auto sparky suggested that it may be the airflow meter or the hydraulic tappits as its fine on idle but not when you give it some.

My first question is do I have to be choosy on the airflow meter, theres one for sale from a 320 mines a 318..is that ok ?

Secondly, these hydraulic tappits...are they expensive as i cant seem to get a price any where ?

As always thanks for any advice

Estee

[dasparkybad]

the 320 airflow meter is not the same as a 318
if you have tapping noises it is likely you will have to change the camshaft / rockers / hydurlic lifters / spraybar as a package as they will all be worn just changing the lifters will have little effect as oil starvation from a blocked spray bar is usually the cause of the problem

[estee]

the 320 airflow meter is not the same as a 318
if you have tapping noises it is likely you will have to change the camshaft / rockers / hydurlic lifters / spraybar as a package as they will all be worn just changing the lifters will have little effect as oil starvation from a blocked spray bar is usually the cause of the problem

cheers dasparkybad, I managed to get an airflow meter offa ebay for 99p P&P 8 quid, well happy , if it works then great, if not it cost me less than a tenner to find oot !