1989 Accord 4 dr carb w/auto trans, not firing on cylinders #3 and #4

[MaroonHonda]

Hello,
After searching, the only thread I found that was similar to my issue is a posting by Tomarano or Tamarino back in 2008; where he states that the engine sometimes just runs on three cylinders. The problem was narrowed down to the head and supposedly the valve guides and other issues that he doesn't state. I am hoping mine isn't a cylinder head issue. A head gasket maybe, but I don't want to remove the head. No garage and it's too damp and cold.
Here we go.
1. I've had car for over four years, and just noticed it running rough about a month and a half.
2. New plugs, gapped properly. New plug wires. A good, but not new rotor and distributor cap. Air snorkel heat valve is closed after warm up, so I'm not getting super hot air in there all the time.
3. That valve on the front, right side of the carb( looking aft) bellows is fine, opens and closes with vacuum suction.
4. EGR valve, I think that's it, with an orange bellows under the lid, moves up and down with vacuum.
5. No vacuum hoses disconnected that I can see. Sprayed ether around while engine running and no increase or smoothing out.
6. Engine mounts are good, new rear one. Front one may be bad, but it really has no effect on this rough running.
7. New gas tank in Sept. that I put in, old one rusted. No leaks, hoses correct and not pinched, no water ingress that I know of as of this typing. New fuel filters and two new fuel lines.
8. New timing belt in April. Running like a champ. Of course though, now I have this rough running.
9. Oil is great, coolant is clean and not depleting. No smoke, after choke fully opens. It may need adjusting, but after car warms up, butterfly is full open. It always has done this, but never ran rough after warming up. No white smoke.
10. This last winter, car even started at 16 below, and for a 25 year old car, that's pretty good. It was great this last winter and summer. Starts up fine since I bought it in October of 2010 every......single.........time......perfectly, whether hot or cold.
Now here's the deal: After warmed up, it ONLY runs on #1 and #2 cylinders. How it is even starting I have no idea. It is missing when I drove it today and last night, and after I got home last night, I disconnected 3 and 4, still sounds the same, no change, and keeps on chugging with just the two cylinders. This missing that started a bit ago, I thought it was bad gas. Because this car starts every time AND I can still accelerate with NO popping, pinging or hesitation. It just kinda seems slow now, however.
When I first start it up, I tested the manifold with water, and each area of the manifold by each cylinder, the water would sizzle and evaporate, and when I would remove each plug wire, the engine would run rough, then when I connected them back one at a time, it would go back up to cold warm-up idle. NOW, after the engine is warm? It only runs on cylinder 1 and 2. Heck, I even crossed plug wires 3 and 4 and NO change.
This has me baffled. The compression on #3 cylinder is 180, HOWEVER, I have not read 1,2 or 4 yet. Because originally, JUST #3 cylinder was not firing after warming up. Now, #4 joined in. And you should here the spark plug wires jumping the gap when I hold all the boots close to the plug tip or valve cover, so there is regular spark going to the plug. Also, ALL the plugs, both my old ones and the new ones I just replaced three days ago, are ALL nice and tan. No coking, oil, water, sludge or what have you.
Whew! Does anyone have any procedures that I may be able to take step by step? I would love to hear your opinions.
Thanks!

[Dr_Snooz]

Could be something clogging the exhaust manifold runners for those cylinders. Have you checked spark on those plugs by pulling them and grounding them to the block? Also check timing. It's possible the timing belt has jumped a few teeth.

[MaroonHonda]

Hello Dr. Snooz,
Yes, I will check the timing manually by lining up the cam gear marks with a straight edge stainless ruler to the top of the head as I have done before and then turn the crank to the proper marks and check that. I haven't done that yet because I wanted to see if it was ignition and I just can't believe that the belt could have slipped because it starts great and I figured if that was off, that it would REALLY run rough and be hard to start.
But before I check that, I am going to pull out plugs 3 and 4 and really look at them with a magnifying glass. Then I will also secure plugs to block and still hooked up to leads and turn over engine to see if sparks are jumping the gaps. Good idea and I was actually thinking of doing that myself.
Then, I will do a compression check of all cylinders when it's still cold.
Then, I will check timing. That would be cool if that was it, but then I will have to inspect belt and gears and any other anomaly to see why it may have slipped.
If timing is okay, I will swap out 1 and 2 plugs and put in 3 and 4 and see what goes.
If it is still rough, that would lead to:
1. Exhaust blockage as you stated
2. Perhaps something blocking the intake runners? I doubt it, but one never knows.
3. Bad head gasket in between cylinders 3 and 4 leaking into each other when engine warmed up, perhaps causing super low compression and misfire/ no-fire.
Thanks, will let ya know.

[MaroonHonda]

Update.
I am here at my work, and was able to check plugs just before I drove it to work today. #4 cylinder plug, which is new, was not working. All day yesterday and driving home last night, #4 new plug was not working. I replaced the plug today, and now #4 cylinder works great. So engine is at 75 percent. Had to leave in a hurry, so I decided to drive Honda since I at least got cylinder 4 going. Drove a heck of a lot better but still missing. Arrived at work, car still idling, took off #3 plug wire, still no change. Took off 4, 2 and 1; bogged down each time, which means even after warming up, #4 plug still working great!
Swapped the known good plug from cylinder 2 and put it in 3 and vice-versa, #2 cylinder still works great, #3 still won't combust.
Took off distributor cap, brought inside, used bright light and magnifying glass, no cracks or other defects noted. But back on cap, made sure new plug wire metal ends are properly going all the way in to the cap. Started up, #3 cylinder still not combusting. Since I'm limited for time right now, I can't check timing until tomorrow or the day after, but I can try the spark plug out of cylinder but connected test, that would at least narrow out distributor and related stuff.
Will keep pressing on!

[89T]

Start testing the internals of the distributer. Bad igniter possibly. Also, If all you did was swap the number 4 plug. The only thing you touched was the wire and the plug? That would lead me to belive you have a faulty wire or cap.

[MaroonHonda]

Thanks 89T, here's another update. After lazying around and going to ma's for dinner and socializing, I got home, and I drove the Honda. 23 miles there, 23 miles back. It was missing, but still able to accelerate on freeway and drive the speed limits.
So after I arrived home and engine still hot, I did a compression test on all 4 cylinders. All four are 180 PSI. So this narrows it down further because when engine is cold, llike 35 degrees, the compression is also 180 PSI on all four.
Then, looking last night, I decided to check timing and it was off, in terms of the cam marks lining up with TDC. So I said AHA! And called it quits for the night.
Now, I just got done removing timing belt, checking everything, lining up to that first hash mark on flywheel, lining up marks on cam, putting on belt, and doing the proper procedures for tightening and after several manual rotations, all three marks are lined up PERFECTLY. Put everything back together, cranked it without ignition to make sure no noise, hooked up coil, starts right up.
Here it was, running super smooth, high idle while choke is trying to warm up engine at about 2300 RPM's, I couldn't even see the engine move, no vibration, pulled off each boot and engine bogged down when I did it to all cylinders.
After feeling the heat from the engine, engine running on all four, exhaust purring like a kitten, I punch the gas pedal to bring idle down to it's mid-state of about 1500.......
Engine starts vibrating, exhaust sounds like crap..........#3 cylinder not firing again.
Left plug in, disconnected boot, put a new plug in the disconnected boot and grounded to engine, fired up engine, #3 wire and plug putting out plenty of spark. Put that known good sparking plug into #3 cylinder.......still a no go.
Just.......what........in the heck..............is going on? It was running super-duper smooth after start up, then after warm up or bringing down the RPM's, #3 cylinder not combusting. I should always say combusting now because I do have a constant, big spark. ARGH!!!!!:uh

[89T]

Read the plug on number 3. Is it fouling out? It would be ideal to check the plug as soon as it looses fire. Check the timing again. Cam and all. If it skipped a tooth again, you may need to replace the belt, tensioner and idler.

[MaroonHonda]

Thanks again 89T, but I found the problem.

Remember if I did kind of state that it ran fantastic when cold? Well, I figured, when really thinking this out, that it was because the choke was allowing a lot of extra fuel going in, thereby running on all four cylinders. But when warmed up and LOW throttle/idle, it didn't want to combust? THAT points to not enough fuel air mixture going to that cylinder.
Low and behold, I just went out and started the car. Verified plug #3 still not combusting but still sparking, I sprayed starting fluid on top of the #3 intake runner, and the car wanted to suck that in like you wouldn't believe! It started accelerating AND running smooth. As soon as I stopped spraying, #3 cylinder is not combusting. Just that half or whole eaten gasket at the #3 cylinder is pulling in enough air to not cause a proper fuel/air ratio.
Un..........believeable! I noticed that two nights ago at work that there looked like a gap, checked it with my thin stainless steel ruler and I thought to myself I need to check that because I didn't have ether or carb cleaner. So after re adjusting the timing belt, which needed to be done anyway, I FOUND THE FREAKING PROBLEM! Un.....real.
So now, I am NOT going to remove the intake manifold. I have this sealer that we use at work that is fuel proof, pressure resistant and strong. It's used to seal aircraft fuel tanks, windshields, and landing gear components. I'll just pooky that all around and let it cure for like 6 hours and I should have a top running car. WHEW!
And thanks everyone. I really appreciate it and I will leave up my posting to aid others when they have just about checked every.....single.....thing...to check EACH intake runner going to the cylinder head.
I will also post a follow up after my sealant has dried JUST to make sure and let everyone know. Heck, I bet if I dripped gasoline on there with an eye dropper it would work. And why that gasket failed there I couldn't tell ya. 99 percent of the satisfaction is FINDING the problem! Thanks again!

[89T]

Nice I would have never of thought of that.

[Dr_Snooz]

I have this sealer that we use at work that is fuel proof, pressure resistant and strong. It's used to seal aircraft fuel tanks, windshields, and landing gear components.

Okay, what is it?

Also, check your timing again. Barring a sloppy install, the belt jumped because it's worn out. Replace it for peace of mind.

[MaroonHonda]

Oh, sorry, I didn't think about naming it because it's expensive and it's only available through mail order. It's PRC from DeSoto Industries. There are many different types in terms of thin and thickness or cure times; in black gray or brown colors, but they ALL have the same properties. You use the runny stuff for sealing cracks and edges, that way it slowly seeps into small areas and it cures in 12 hours. The 1826 B 1/2, when mixed up hot, will cure to hardness in 20-30 minutes. You see, when the lots expire as per Aviation rules of shelf life, they are basically still good for up to three months. So every now and again I check the flammable waste room for expired stuff and take it home. We usually get the stuff in what is called Sem-Kits. It is in a tube, about half the size of a regular caulk tube, there is a special machine that spins/mixes it as you slide the tube up and down, then you need the special caulk gun to apply it. Me, I mix it in my drill press and then push from the bottom with a screw driver.
And thanks Dr, but the belt I installed back in April had slack to it because I did not do the proper tightening procedure and therefore it could have slipped as I mentioned the timing was off, but not enough to really notice. I used that belt after inspecting it and it still looks brand new. I'll see if I can post a link to PRC.
Later and thanks!

[MaroonHonda]

Okay, here's the link. Ya just gotta search around for whatever is the best in terms of high temperature and/or quick cure. Usually, the 1826 is fantastic. I forgot actually how many different types there are.
Fast Cure / Flight Line Repair - Aerospace Sealants - PPG Aerospace Home

[MaroonHonda]

And here is the application gun if ya want.
Semco® Model 850 Manual Gun Distributed By Bergdahl Associates, Inc. | Bergdahl Associates INC.

[Dr_Snooz]

There are a lot of wonder chemicals in the aviation industry. Marine applications also have a lot of really amazing stuff too.