Running On 5 Cylinders

[Mr Toad]

Hi,

I have an 1989 m20 525i that has recently started running on 5 cylinders.
I could smell fuel coming out the exhaust so i looked at the spark plugs and saw no.5 cylinder plug was wet.
I've tried swapping the ht leads over, changing the spark plugs and a new distributor cap plus rotor but its still not firing.
What else is there to look at?

Also i notice on ht lead for cylinder 6 there is a circle thing round it that goes off somewhere else. What does it do?

Thanks

[joshua43214]

If you have eliminated all the ignition parts, plug, wire,cap,rotor, then its probably time to run a compression check.

the lead is to time the batch firing forthe injection, it will run with out it connected, but not as well

[Mr Toad]

ah i forgot to say i did a compression test in fear of valves but it seemed fine.
I also did a stomp test and nothing came up.

[joshua43214]

ah i forgot to say i did a compression test in fear of valves but it seemed fine.
I also did a stomp test and nothing came up.

Silly question I know, but after replacing the plugs,wires,cap and rotor, are you positive the misfire is still on number 5? I have seen aftermarket caps be bad out of the box. Also, if #5 was flooded enough, it may have fouled the new plug right away, this could be especialy true if you put in crappy Botch platinums.

you said the compression test "seemed" fine, what where the numbers?

If all the ignition parts are good, and compression is good, maybe you have a missing injector o-ring, or even an injector that is dumping fuel.

[Toomas]

Does she run well on high rpm?
Maybe cyl 5 gets flooded, change the injector if you can and see what happens.