Chim rough @ 1800 RPM

[debaron]

Hi all,

Got a rough running Chim around 1800 rpm. Doesn't feel down on power but sounds and feels lumpy and rough approaching 1800 then getting less so up to around 2200 when it feels ok. Is the same while static or driving so not a transmission problem.

Haven't had chance to take a look yet but any ideas?

Things I have in mind - Rotor arm, HT leads, dizzy cap.

Did do the plugs recently, Gapped them out a little too. Maybe too much? Could that cause a problem? Any ideas why just at 1800 rpm?

Cheers

[daz the plumber]

hi, ive had the same problem , mine idles nicely , then if you slowly increase the revs the car does not seem to be running on all 8 cylinders untill 1800 revs , after 1800 the car goes fantastic .i think mine is a fueling problem ,

[PRTVR]

Some things that might be worth checking,
lambda probe fault...the engine is not getting the correct information on how rich or weak the mixture is, leading to rough running.
distributor centrifugal advance mechanism stuck on fully advanced, (unsure as to what revs this changes things ) but I am sure some one will be along to help you out with this.

Phil

[P100]

Hi Guys.
Had this a few times with other V8`s...
Try disconnecting the alternator then drive it down the road.
If the rough patch has gone, fit a new rectifier to the alternator.
I have found that if the diodes are breaking down this corrupts the signal to the dissy causing the rough patch, buy only at around 1800 to 2000 rpm.

Of course, it just may be a HT lead breaking down..

HTH

Roy