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Running on 5 cylinders

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Slider748

Slider748

Senior Member
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I finally got my vehicle back on the road after about a year of repairing things and to my surprise the engine is now missing on the number two cylinder. I checked the valves, spark plugs, wires, compression and everything seems fine. Any idea where the problem might be? I am using a Petronix ignition and the cap and rotor are fairly new.
 
Did the car run at all in that year while off the road? Did any problem exist before taking the car off the road? Assuming the answer to both of those questions is no, I would look at the items that would isolate a problem to one cylinder. Valves wouldn't change from sitting. Electronic ignition and rotor failure would cause the car not to run. The only way I can see failure in one cylinder with the ignition is if you have a bad magnet on the donut. This could be checked be by turning the donut a flat on the shaft to see if the deadness changes to a different cylinder. A damaged or corroded cap could cause a problem, but that would be unlikely. Wires can be tested by putting #2 wire on another plug,leaving #2 plug disconnected. If it runs worse, bad wire. A new plug is inexpensive to purchase and easy to change. It could have gotten washed out which can cause spark failure and would leave the plug very clean. Plugs and wires would be my first place to look.
I'm sure you have checked all of your connections. Do a compression check if the plugs and wires don't end up being the problem.
Good luck and let us know what you find.
 
hi,
i assume you put a timing light attached to the missing cylinder HT lead to check for power to the plug? if you have power,change the plug, even if it's new, or swap plug from a different cylinder.
rob
 
Slider
I just had the same problem. I had new plugs, and after changing them it works fine. Even a new set of plugs can contain a dodgy one. Try Robs suggestion and replace the plug to see if this helps.
Regards
Craig
 
Thanks for the advice everybody. I tested each wire and spark plug and all are good. Compression is near 180 for all 6 cylinders. Is it possible to have a worn/damaged valve guide and still have full compression? I think it's a valve guide because there is some smoke on deceleration.
 
The blue smoke could be unburned fuel. Have you rotated the magnetic trigger wheel to see if it changes cylinders? Try swapping plugs between cylinders to see if that makes a change as well. If you have a misfire problem, look at electrical solutions! 180 psi in all cylinders would most likely not be a valve guide sticking. A loose valve guide shouldn't cause a misfire. Did you do an Ohm test or a "wiggle" test on the plug wires? Or did you just check for a signal with a timing light?
 
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