Number 2 cylinder not firing

[LuckyWinner]

Ok, got spark to number 2 cylinder, but its not firing, header cold to the touch, why are all cylinders firing except for number 2 cylinder????? no EFI, have carb.

[2bking]

Have you checked the plug gap? If EFI, check the electrical connection and swap injector with another cylinder. Check compression on #2. You know the rule, spark, fuel, and compression and all at the right time, it should work. Make sure all of the other 7 are working as you could have a plug wire swapped with another cylinder.
Good luck

[Bob Cowan]

Could be a lot of reasons; but having a carb makes troubleshooting a little easier. . I would start by checking valve adjustment. If that's OK, I would do a compression check.

[LuckyWinner]

Could be a lot of reasons; but having a carb makes troubleshooting a little easier. . I would start by checking valve adjustment. If that's OK, I would do a compression check.

Can you explain how to check valve adjustment?

[carlewms]

Lucky,

This link might help:

http://youtu.be/3xM1v1HZ2Wg

Carl

[lazrcng]

.......I got spark to #2, but it is not firing.........

I am guessing you checked spark at the wire before the plug. If so, it is a bad plug, try a new one.

[CraigS]

I am also thinking plug. If there were a valve adjustment problem you would still get something happening in that cylinder. Might not be 100% but it would still fire and heat the header at least somewhat. An easy test would be to swap plugs w/ the cylinder next to it and see if that cylinder doesn't fire then.

[Jeff Kleiner]

...If there were a valve adjustment problem you would still get something happening in that cylinder. Might not be 100% but it would still fire and heat the header at least somewhat...

Unless the intake valve was not opening such as from a pushrod or rocker being off. In that case the pipe would be cold (aside from friction heat due to the piston moving up and down) but there wouldn't be any other telltale besides running rough. That said though the easy check is to pull the plug and if it appears OK visually then swap it with another hole and see if the problem stays with the cylinder or spark plug.

Jeff

[Bob Cowan]

Can you explain how to check valve adjustment?

http://www.compcams.com/Technical/Instructions/Files/250.pdf

The big trick with valve adjustment is finding zero lash. The standard instructions are to tighten the nut until you can't spin the push rods with your fingers. But with modern materials and lubes, you can often spin the push rod well past zero lash.

Tighten the nut by hand. When you can't turn the nut by hand any more, that's zero lash. Then add 1/2 - 3/4 turn.

[LuckyWinner]

I have spark, saw it as it ground out on the body. so pretty sure its not wire, plug or distributor. the header gets just warm to the touch while the others get to hot to touch. No sounds other that airy sound coming out of the exhaust.

[LuckyWinner]

how do I know when im top dead center for 2 cylinder and do I need to be there to check out if anything is wrong. Going out to get a compression gauge this afternoon.

[OVCobra]

Checking the spark plug out of the cylinder does not necessarily mean it is OK...plug may not be firing under the pressure of the cylinder during compression. Either put a new plug in or as Jeff suggested above, swap the plug with another cylinder and see if the problem follows the plug or not.

If the plug does not solve the problem, check compression or leak down as noted previously. Need 3 things for combustion; fuel, spark and compression.

Good luck,

Dave

[LuckyWinner]

have checked and changed out spark plug and wire, same issue, have a carb, so cant imagine why 2 cylinder would be the only one not getting fuel. so I think im down to compression and am hopping that its something simple to fix.

[Norm B]

If you have spark then something is stopping the air and fuel from getting to that cylinder or preventing compression. A problem with the valve train is the only thing that can do that aside from a hole in the piston or a blown head gasket. Those last two conditions are unlikely to show up without other indications. I suggest you pull the valve cover on that side. It is quick to do, and anything wrong should be easy to see. If you can, turn the engine over slowly without starting it, and watch for the valves to cycle on the #2 cylinder. Have a rag handy because oil is going to squirt out the top of the pushrods and rockers.

Good Luck
Norm

[CraigS]

Lucky, I was hoping for you it would be something simple like a dead plug. Dang, seems it may be more than that. Keep us posted.

[LuckyWinner]

Problem solved. Took off the valve cover and the intake valve for 2 cylinder, when it was closed , there was no play in the rocker arm....while all the rest of them when they were closed, had just a little play. So it looked like even when the valve was supposed to be sealed and closed...it was open just a little. So I adjusted the rocker arm so that there was just a little play, and no pressure on the valve or spring....problem solved!!!! number 2 cylinder is now firing....thanks everyone, and just happy it wasn't something worse.

[Bob Cowan]

Great! Glad it was something simple, and free to fix.

[Norm B]

Great news. Easy fix at no expense is always good.
Norm

[Jeff Kleiner]

Glad it was easy! With the intake hanging open I'm surprised you weren't getting a backfire through the carb.

Jeff

[CraigS]

I am glad you found it but I wonder what the root cause was. A hydraulic lifter should self adjust.