F22A1 Cylinder #1 Misfire

[Flyingsheep]

I was driving home last night and the engine started randomly jumping. Right before I arrived it got worse to the point where it was basically running on 3 cylinders. So now I'm trying to diagnose what exactly is the problem and was wondering if I could get some insight. When I start it (cold or warm) it idles extremely low now (like 200 rpm) and sounds like it's running on 3 cylinders. When I drive it around it sometimes jumps where suddenly all 4 cylinders are working again and feels smooth, and then starts misfiring again. It seems to be random no matter what RPM. I figured out that it's cylinder #1 because when I unplug the injector it makes no difference, but if I unplug any of the other ones it almost dies.

Here's what I've checked:

-Spark plugs (they all look normal)
-Spark tested all plugs (there is spark)
-Compression tested all cylinders (#1 170 PSI, #2 180 PSI, #3 180 PSI, 4# 180 PSI)
-Tested all injectors with screw driver to my ear (I hear clicking from all of them, even at cylinder #1)
-Checked all ignition cables with a timing light (didn't see any misfiring, and they all synchronized with the engine)
-Checked and eliminated all vacuum leaks
-Cleaned IAC
-Swapped in my F22A1 ECU (been using a P12 ECU. No change in misfiring)
-No check engine lights

Anything else? It doesn't seem like it's the distributor, being that there is spark and the timing light doesn't show anything unusual. I think the diagnosis system is too old to have the technology to detect misfires, since this is a 1991 Accord. This is my daily driver and only vehicle so I'm kind of in an emergency...

Thanks

[oyajicool]

Swap injectors #1 and #2.
If #2 misfire now, then, for sure, you know what that means.

[ExplodingCake]

Since you have unplugged the injectors and #1 didn't show any change in rpm , it's a red flag.

[dj_ender]

What happens when you pull cylinder #1 plug wire while the car is running? If nothing, it's likely you have a bad wire. Next thing to check, a leak coming from the intake gasket around cylinder #1. But honestly, I'd be more inclined to think it's a bad wire, or the clip inside the wire isn't fully seated on the plug.

[jhondayaaj]

You don't have a bad wire. It obviously a bad injector causing it.

[dj_ender]

You don't have a bad wire. It obviously a bad injector causing it.

Care to explain that? The OP has already stated that the cylinder 1 injector is firing, and if you are going off him saying that when he unplugged cylinder 1 injector it did nothing, it could still be the wire.

[Flyingsheep]

I just swapped Injecter #1 and #2. Nothing's changed. Cylinder #1 still misfires and is unaffected when I unplug the injector. So that eliminates the bad injector idea.

I'm not sure if I'm seeing how unplugging the wire for cylinder #1 will show me anything to be honest, since it already does nothing when I unplug the injector. If it's already not firing and I unplug the wire, that doesn't tell me anything. I spark tested that wire and it's got good spark.

On the side note, it seems to run on all 4 just fine and perfectly smooth when I start it cold, but once it warms up cylinder #1 is pretty much gone.

[dj_ender]

Well from the sounds of it you're getting fuel AND spark in cylinder 1, so really all that's left is a break in the intake manifold gasket, or a loose intake manifold nut.


Edit.... Any change if you swap cylinder 1 and 2's wires?

[Flyingsheep]

Hmm. I've never taken the manifold off so technically there shouldn't be a gasket problem, but I wonder if it's the EGR passages being clogged? I know on this car it's a pain to clean them because you have to drill out the plugs, which I don't feel I have the expertise to attempt.

I can take the manifold off if a machine shop is able to clean them out?

[dj_ender]

Doesn't matter that you've never pulled the manifold, the gasket can still fail.

[Flyingsheep]

I sprayed carb cleaner around the intake manifold and the idle was unaffected. But I'm going to take the manifold off anyway, and see if a machine shop can drill the EGR ports. That way it'll get a new gasket when I put it back on.

[dj_ender]

Is there any change if you swap cylinder 1 and 2's plug wires?

[Flyingsheep]

What? Wouldn't that screw up the firing order and cause it to not start or barely idle?

[dj_ender]

I mean swap the wires, even at the dizzy. I'm curious if your wire is leaking voltage into the cylinder and causing the misfire.

[Flyingsheep]

Damn. I think that's it and you are right. I swapped them and now cylinder #2 misfires. I remember now when I spark tested the plugs, one of the wires shocked me when I wasn't even touching it. That explains it. It's probably leaking...

I'm going to run to the parts store and grab a new set of wires and let you know how it goes.