mikeb Posted September 17, 2010 Share Posted September 17, 2010 hello every one have a little problem with my v8 replaced the ignition ampfiler in the dizzey and the coil got it to run but only on five cylinders. If i pull the lead off the plug it makes no diffrance could this be the cap or rota arm or worst of all head gasket failure. any help ideas would be greatfull. Quote Link to comment Share on other sites More sharing options...
mickeyw Posted September 17, 2010 Share Posted September 17, 2010 Could do with a little more to go on Mike. Was the engine running before you replaced the coil and ign amp? If the engine has not run in a long time, Check plugs are clean and correctly gapped. If any are particulary rusty it could indicate water ingress via bad head gasket, Check condition of plug leads, Check for white/green corrosion where leads plug in to cap Check inside of cap for crud on the contacts, outside for signs of cracking/damage. Clean end of rotor arm with some fine abrasive paper Check you have good clean petrol coming through If it still won't run right, you could relace the cap and arm, preferrably with genuine parts. Some pattern stuff is notoriously likely to cause problems. Next you could try a compression test. If any cylinders are low it may indicate any of the following - rings stuck/worn, valve sealing issues, head gasket issues. I'm not 100% on pressures to expect but I believe anything lower than 120 PSI isn't great, but it should still run like this, albeit not as well as it should. Quote Link to comment Share on other sites More sharing options...
oakesy Posted September 18, 2010 Share Posted September 18, 2010 Could do with a little more to go on Mike. Was the engine running before you replaced the coil and ign amp? If the engine has not run in a long time, Check plugs are clean and correctly gapped. If any are particulary rusty it could indicate water ingress via bad head gasket, Check condition of plug leads, Check for white/green corrosion where leads plug in to cap Check inside of cap for crud on the contacts, outside for signs of cracking/damage. Clean end of rotor arm with some fine abrasive paper Check you have good clean petrol coming through If it still won't run right, you could relace the cap and arm, preferrably with genuine parts. Some pattern stuff is notoriously likely to cause problems. Next you could try a compression test. If any cylinders are low it may indicate any of the following - rings stuck/worn, valve sealing issues, head gasket issues. I'm not 100% on pressures to expect but I believe anything lower than 120 PSI isn't great, but it should still run like this, albeit not as well as it should. Second that. There is a spark plug tester that can sit between the lead and plug. This will show any spark or no spark. Quote Link to comment Share on other sites More sharing options...
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