alovins

hi i have a 1999 honda civic hx and this morning i started my car and it started really rough and noticeable something was wrong. The engine light turned on and started blinking. Shut the engine off, and got the code back as cylinder 2 miss fire. I was reading some horror stories. But I also read that it could be the exhaust manifold being cracked. I checked the manifold and there seems to be a little fracture crack, nothing huge but I didn’t think that little crack could be causing that big outcome. I just don’t know if a cracked manifold has to be a large one to cause these symptoms. But this morning was the first day that it was close to freezing out. I read that cold could be a sign of cracked manifold. If anyone could maybe tell me if I’m on the right track or where to look or to confirm it is the manifold. Thanks

ezone

Get the engine to act up, actually misfiring.
Tap on the #2 injector with a screwdriver handle (or something of similar weight), see if it starts running correctly again.

Actually, tap on the other three also if tapping on just #2 doesn't help.

The injectors can stick shut, the stuck one won't inject fuel if it happens.


If that isn't it, then troubleshoot other stuff.

alovins

I checked the injectors with a screw driver i can hear them ticking, engine light went off, still rough running. what other areas should i look at now?

ezone

You SURE all are clicking?
Even if only one injector was clicking, you can normally hear it throughout the entire set of them. Hard to tell, even for me. (I could be going deaf too, FWIW.)

Did you TAP on each one like I suggested?




Anyway...
Rough running, but with no CEL?
Are you positive it is still misfiring, or have you just not allowed it to run long enough to turn the light back on?


Next:

Verify which cylinder is misfiring.

Compression check and common ignition checks.

Gotta have compression, spark, and fuel. All in the proper amounts, and at the correct times. What part of this is wrong?

alovins

ya i did tap on them like u say, and i dont know maybe im deaf too! i did a compression test and the results were
140, 130, 125, 140
changed the spark plugs too.
those compressions are not too bad i thought. but you tell me what you think.
thanks for the feed back!

ezone

Should I assume these were numbers 4, 3, 2, 1, respectively?
That would make #2 the lowest number if I guessed that right.
(#1 cylinder is closest to the belts.)


Is one much darker than the rest? Which one?
Actually they are all quite low to me, but the methods you use to obtain the readings may have everything to do with those results.

I disable the ignition coil so it can't fire,
pull all the spark plugs out,
prop the gas pedal down with a stick,
make sure the battery is fully charged,
attach gauge,
crank it until the gauge stops climbing. Keep cranking a bit more just to be absolutely certain. Probably more than 10 hits per cylinder.
Repeat for all cylinders.




On a "cylinder contribution test", is the bad cylinder doing ANYthing at all?

alovins

The compressions are from cylinder 1 to 4 so the lowest was 3

The spark plugs looked about the same, nothing outstanding difference. looks like the engine might be running rich.
I did the compression test exactly like what you said, took all the plugs out, disable the ignition from the coil, stepped on the gas all the way. And let the engine crank about 5 times on each cylinder.
what should the compressions be then, cause i thought there would be a considerable diffrence in a cylinder if something was wrong.

ezone

This is where the difference lies, I bet. I keep cranking until the gauge stops climbing, then keep going some more.

Use another person if you have to.


Altitude plays a large role in the compression results.
High altitude would cause lower readings yet still be perfectly normal.

Slow cranking speed would cause low numbers too.

Gauge inaccuracy too.

10% difference (maximum variation) between any 2 cylinder readings is the industry standard.
But you must have proper results in order to make the comparison.
I would tell you that your test numbers have 10% variation, but I can't say that because I don't know that you have accurate results from your test.

The low cylinder result you have obtained doesn't correlate to the misfire #2 code at all..


I'd expect 180-220 PSI for almost all the Hondas I see these days.

If there is not a considerable difference between cylinders, then look elsewhere for the problem.


HTH

alovins

hey ezone, my Honda has not been acting up since i have talked to you, until yesterday. Started it up and it started shaking again, rough and engine light came on. Thankfully i wasn’t too far from home. Driving it home it was rough but was interesting is that I soon as it warmed up, it was gone, ran fine, engine light stop blinking?! What do you think of this? I still have a cracked manifold, and the o2 senor wires are frailed so i though based on that the misfiring stop after it was warmed up, it was the o2 sensor and manifold. What do you think, thanks.

ezone

Do you try what I suggested earlier?

Let me refresh you:
You missed your opportunity. This must be done WHILE the problem is acting up.