Consistent misfire on cyl #2 Weber 32/36

Since installing the Weber I've had no luck firing on cylinder 2. I've replaced the ignition coil, all the plugs and wires, rotor, and the cap, still misfiring. I've checked and I do have spark, but when i unplug #2 wire there is no change in idle. Last summer I changed the head gasket, along with intake and exhaust manifold gaskets. Timing belt is relatively new, less than 10k miles. My air fuel gauge shows a good mixture with the idle adjustment screw almost bottomed out, and the car runs rich on acceleration. I've been chasing this gremlin for almost 3.5 years and I dont want to retire this car until its rotting apart. Thanks!
Dillon

Could be a stickey valve or a valve out of adjustment. I'd do a compression test on all cylinders.

Is the plug fouling?

I'm sure the plug is fouling, when I did the head gasket I manually turned the cam to see if all valves worked and they do, could a bad valve lash really cause it to never fire? It most definitely still pulls gas into the cylinder and pushes it out unburned

Yes it's possible. I'd really start with testing things. A compression tester can be rented from your auto parts store for free. Post the numbers here.

I'll try and make time for it in the morning, I'll post numbers as soon as I get it done. Thanks guys

Didnt find time for a compression test, pulled the plug however and it's a pinkish tan which I'm sure is close to normal so I'm just completely confused.

What are the symptoms leading you to pull plug wires?

Ever since I got the car I've tried everything to make it run smooth, and it's always misfired on cylinder 2, nothing made it show improvement. I've always heard pull the wires and listen for a change, there isnt any change in sound when I pull wire #2, and the plug shows a tan color, so I'm not sure that spark is even the issue, I'm waiting to do a compression test when I get a chance from work

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Originally Posted by FatPickle

so I'm not sure that spark is even the issue

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Yeah, pretty much what I was angling toward. Have you checked vacuum leaks and motor mounts? How often is the car driven? How bad is the roughness? Beyond pulling plug wires, how are you determining that this is a problem in the #2 cylinder?

I just recently fixed a vacuum leak around the adapter plates for the weber,
I drive it everyday, and I haven't fully determined that it is only second cylinder. I'm gonna do compression test later tonight. I'm pretty sure it's only ever misses on one cylinder though, the motor is pretty peppy for having a bad misfire.

Does the engine run ok when you floor iT , or does it still misbehave ?
If it cleans up and runs ok with plenty of throttle , i'd say manifold gasket .
If all the plugs are nice and clean , it suggests there isn't anything amiss with the ignition side of things and its either getting to much air ( vac leak ) or is lacking compression ( tight tappet or something more sinster , at which stage a comp test is a good place to start .

The misfire never cleans up, even with revs I can feel the vibration and lack of power. It has less than 2000 miles on the intake and exhaust manifold gasket

Swap a couple ignition leads around and see if the miss follows the lead .
If it doesn't , start with the simple stuff. start with plugs , check the cap and rotor , then comp test etc

So as weird as this may sound, today after a few things, the idle cleaned up almost perfectly. Just an occasional sputter. I started with compression test. It showed 60 psi on the problem cylinder. So I pulled the valve cover and checked all the valve lashes. All the exhaust side was tight and needed a minor adjustment. Maybe .001 off. Once I put it all back together, I started it thinking I was gonna just be out of luck, and it was smooth! Not perfect but hey, I haven't heard a smooth idle for even a second in my 5 years of ownership and 2500 in parts trying to sort everything.

Although I still haven't managed to make it tidle smooth without having the distributor adjusted all the way counter clockwise

Is your timing belt off by a tooth? How are you setting timing?

What was your psi on the other cylinders?

I set the timing using the Mark's on the flywheel, crank pulley, and cam gear when I changed head gasket. However, when I was checking for a stuck valve, I turned the motor over backwards which may have advanced the timing gear by a tooth. So theoretically, since my dizzy is ALL the way counter clockwise I could still be a tooth off.

The cam gear, not "timing gear" I just woke up, if you cant tell 😂

Other cylinders were good. I'm honestly thinking that the little bit of compression was lost through the compression tester itself, because my spark plug threads are junk, I'm putting in a helicoil soon to see if that makes it better

If you're maxed on the adjustment for the dizzie, then that's telling you something. It's relatively easy to check TDC.

That's the weird thing, at tdc the flywheel mark T lines up with the needle and the cane gear lines even with the head, so is there any way the cam gear could be on crooked, because I know the crank pulley has a key way so it cant be installed wrong

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Originally Posted by FatPickle

Other cylinders were good. I'm honestly thinking that the little bit of compression was lost through the compression tester itself, because my spark plug threads are junk, I'm putting in a helicoil soon to see if that makes it better

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They make a cheap plug thread chaser might be worth cleaning up the threads real well and like said above double check you are at TDC and the cam is in the correct place.

I agree with old blue, i would try cleaning up the threads instead of going straight to a helicoil.

No way your flywheel or cam gear are off by a little. It sounds like you are at TDC. So i would deal with the issue of your spark plug threads as that seems to be a concern for you. Then if you get that fixed your compression numbers should be similar on all cylinders which would make adjusting your distributor easier. On my car I had my distributor maxed out one direction to get the car running better, it turned out to be my exhaust manifold was loose and leaking causing the O2 sensor to read incorrectly making it run it rich. When i fixed the exhaust manifold, I adjusted the timing with a timing light and it went back to the middle. Car ran much better too. I'm not saying your manifold is leaking but you need to look at everything.

Are some of your spark plug holes dirty as if exhaust is leaking out of them?