odd-fire miss got me stumped

OK, I am hopeing that someone here can help me with this, or maybe even has had a similar problem. Sorry about the length, I wanted to get the details in.
After installing my new carb I was able to uncover another problem. Now that the fuel is getting to the engine I have a miss that I am fighting. The easiest way to describe this miss and the thing that has me really confused is that if I pull the plug off the offending cylinder (#4) the engine actually smooths out and picks up rpm! It is bad enought that the engine is really really rough at idle (barely running), doesn't smooth out till 1500 + rpm.

I have gone through the ignition, new plugs, checked the wires (accell 8mm), confirmed firing order, checked the pickup position, checked for spark at every cylinder. Timing and firing order etc were setup by the info in the link in the tech section.

The exhaust on the pass bank is definitly cooler than the drivers.

I have noticed what I would call a valvetrain noise under the valve cover( good place for it I figure). this leads me to believe that the valves are not operating correctly, affecting timing, causing the removal of spark to smooth out the engine.......

Have not checked compression yet as I do not have a guage, should get one this week.

I am at a loss at this point, my only idea is a bad lifter or other valve train problem causing a wacky timing situation.........

Thanks for any advise or experience you have.

 

Possibly a valve stuck open, and my guess would be an intake valve

easy enough to pull the valve cover to check it out in there

 

my first thought is you have 2 plug wires crossed.
my second thought is incorrect/damaged dist rotor; no long tang that the V6 requires
this assuming of course you still have a stock distributor.
removing the plug wire, and the engine smooths out, indicates to me that you do have good compression on that cylinder, no stuck valve. If you had very little or no compression, there would be almost no change when the wire is removed.
I'd take a good look at your distibutor and ignition components again.

 

Hey guys thanks for the quick replies :stout:

I forgot to say that it is an HEI disributor with adjustable vacuum advance, and I reconfirmed tonight it is a proper odd-fire setup (pickup lobes,tone ring, cap, rotor) .

I pulled the valve covers, and the valve all appear to be working correctly, nothing hanging up, moving late, or not moving as far as the rest.....

I confirmed firing order again, and that at TDC for number 1 the rotor tip lines up with the "wide" pickup. I did notice that the CJoffroad instructions CJOffRoad shows the lobe tip for the pickup inline with the rotor tip for the cap.




Mine is not in line with the rotor tip, it is about 30 degrees clockwise farther when looked at from the top. Or if looking at the above picture it would actually be to the right of the lobe pictured. Sorry I don't have pictures of mine.

Before I rip my distributor out, is the lobe set removable so I could re-clock it, or am I just grasping at straws and this is the way a true odd-fire hei is? I can't imagine you would want to initiate the spark before the rotor was aligned with the cap......

This would advance the spark a signifigant amount, effectively firing the plug while way too far from TDC on the compression stroke. And since you can run much more advance at higher rpm due to rate of burn etc, that may be why the thing smooths out a bit at rpm..

Any more thoughts, or do I need to give the pipe back?

 

Compression test??

Easy to do and is non invasive.