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[Webby the Bear]

Hi ya,

This is defo coming from the 1,3,5 bank. And I'm thinking one of these cylinders is misfiring and causing that tractor sound and rough idle. What do you think?

I want to do a power balance test i.e. pop the spark plug leads off 1 by 1 and see if the engine changes... where it doesn't I've found the cylinder misfiring. HOWEVER, is it safe to do this ?

 

[Webby the Bear]

right, just googled this stuff... can I wear rubber gloves to do this and that should protect when popping a ht lead out when cars running? not convinced personally

[Webby the Bear]

i'm so stupid. I could just pull the ht lead when its off then turn car on. soooo dumb at times 

[Webby the Bear]

Right allo sorted...... I think . made a quick video of the problem. when HT leads removed the engine changed for the worst on all leads individualy. then I was like ''hmmm whats that hissing noise''......

[Kevin Wood]

Such a test won't work on a wasted spark setup like the Omega has since pulling one lead actually kills 2 cylinders.

In fact, it's really only relevant to old cars with distributor based ignition. You also have to be very careful about modern ignition systems when they are running. The spark energy is so much stronger that a shock from a deteriorated plug lead can be dangerous. I reckon you could also kill a modern coil pack doing that.

Most modern engines either detect misfires and raise a code to tell you which cylinder it is, or provide a mechanism for you to cut individual cylinders via Tech2 (or equivalent dealer diagnostic interface).

As to the noise, difficult to say from a video but it's certainly missing a few cylinders and not sure what the rattle is. Sounds like air getting in somewhere too.

[Webby the Bear]

Such a test won't work on a wasted spark setup like the Omega has since pulling one lead actually kills 2 cylinders.

In fact, it's really only relevant to old cars with distributor based ignition. You also have to be very careful about modern ignition systems when they are running. The spark energy is so much stronger that a shock from a deteriorated plug lead can be dangerous. I reckon you could also kill a modern coil pack doing that.

Most modern engines either detect misfires and raise a code to tell you which cylinder it is, or provide a mechanism for you to cut individual cylinders via Tech2 (or equivalent dealer diagnostic interface).

As to the noise, difficult to say from a video but it's certainly missing a few cylinders and not sure what the rattle is. Sounds like air getting in somewhere too.

It is Kev, I just posted the vid on it 

[martin42]

have you still got ht leads running under the plenum??

[Webby the Bear]

have you still got ht leads running under the plenum??

put them back mate 

[martin42]

was it running ok when you put coil pack back to original position or happened a while later?

[Webby the Bear]

was it running ok when you put coil pack back to original position or happened a while later?

yeah it was after, martin. was running fine before that. i'm picking up the breather bridge 'o' rings Friday so ill put them on and see if the miss goes. if not then ill recheck all my connections and replace ht leads if I find a fubard one 

[tunnie]

Just goes to show, original place for DIS pack is best 

[Webby the Bear]

Just goes to show, original place for DIS pack is best 

lol it ran fine in the new position... its now back and runs shite 

[martin42]

sounds like you might have damaged some of the ht leads then,got any from ralf you can swap them over with

[Webby the Bear]

sounds like you might have damaged some of the ht leads then,got any from ralf you can swap them over with

yes mate. got loads in fact 

[cem_devecioglu]

Webby check the sparks condition.. and there is an obvious air leak..