o-one

I have a 99 integra LS Stock, my check engine light came on. I checked the cell and it gave me a 71,72, and 74 meaning random misfire on cylinder 1,2 and 4. I did a tune up, first i changed the spark plugs wires with blue NGK's still had the problem. I changed my spark plugs with NGK's still had the problem. Then i changed the distributor cap and rotor (OEM), checked the code and told me it was only misfiring on cylinder 2. Drove to work and now im back at cylinder 1,2, and 4 misfiring. I reset the ECU (Battery disconnected) My engine is running Smooth no problems, still showing the cells. what can it be?

UPDATE!
So i solved my issue. I did a compression and I was getting 0 compression on cylinder 2. Turned out to be a 1 cracked/burnt exhaust valve. Got the valve replaced, cylinder head resurfaced & cleaned,its now running like a champ. No more cells, the weird thing is that i was getting a random misfire on 1,2 & 4, but i guess that did the job.

TheRealTegger

Firstly, the term "misfire" does NOT mean to go tackling the ignition system. In OBD-II parlance, the word "misfire" is NOT being used in the way you'd think of when it comes to firearms or firecrackers.

Secondly, you really should be reading the proper OBD-II codes. The MIL blinks only give you a rough idea of what's wrong. You need to know if there's a P0300 mixed in there, or if you've got P0301, P0302 and P0304 only. This is important.

Multi-cylinder misfires are usually due to intake-manifold leaks, EGR blockages, and that sort of thing.

wunfstgsr

check your wires if there in correct firing order, check your timing! use a gun and make sure its timing is on, my timing was off and it was giving me miss fire codes.

Rahes

I was in the same boat, missing cylinders 2,4 did a compression test and failed on those 2 cylinder. Ended up having 6 bent exhaust valves. Run a compression test.

HStrolling

I agree with Rahes, needs a compression test. Could also be an injector not working properly.

o-one

thanks for the replies, i effd up my ignition coil when i unplugged the spark plug wire for cylinder 1 while the engine was running. Bought a new one and installed it. The cell is now only throwing a 72, ima run a compression test to see what i get. Ill switch up my injectors today to see if anything is wrong with them. ill get on the code also, ill try to get a the scanner.Thanks again.

Vizio2012

I got misfire on 1 and 3 on my 99 si, Seems every post i go to there is no final verdict. Just unanswered threads??

seanbev24

The biggest problem is most people don't understand the amount of things that can cause misfires. No offense to the OP, but he is a good example of what most people do- throw parts at the problem without diagnosing it. It's cheaper to pay a tech an hour of diagnostic labor than it is to replace parts until you get it right.

Next, YOUR CARS ARE OBD2! You can buy a cheap scan tool that's capable of showing live data and freeze frame data for the cost of those NGK plug wires that didn't fix the problem. While not required, a scan tool makes diagnosing things easy if you learn how to use it. It usually won't tell you the answer, but it gives you the ability to know which direction to look before even popping the hood.

Also, sometimes the codes are wrong, so you need to confirm which cylinders are actually misfiring. I've seen an Odyssey with 1 dead cylinder throw codes for all 6 cylinders. All it needed was 1 coil-on-plug. A constant misfire is easy to confirm by pulling plug wires or unplugging injectors, but an intermittent misfire is more difficult. With better scan tools you can get into the misfire monitors and watch the counts. Often times you'll find that although there's a code for 1 cylinder, multiple cylinders are having issues. A Mercury I worked on last week only showed a #5 misfire code, but all cylinders were running lean due to a weak fuel pump. Here are common causes of misfires...

-No/weak spark (plugs, wires, distributor, wiring, pcm, etc)
-Too much or not enough fuel (fuel pump, filter, stuck open/clogged/shorted injector, wiring, pcm, etc)
-Vacuum leak
-Stuck open EGR or clogged ports
-Timing
-Compression

I'm not trying to be a dick. I'm just trying to explain that it's a bit more complicated than getting new spark plugs.

el crapitan

absorb those few paragraphs, people. all very valid points and great advice

Huss

i am having the same problem with my 00 si/R... but on cylinder 1,2,3

within the last 40,000kms i have done the timing belt, water pump, tensioner all at honda and a valve adjusment.

today i did the plugs, wires,cap, rotor.....


when i pulled the plugs they looked like the car was running hella rich....and yes my fuel economy dropped too... also i get a bit of vibration and rough idle when idleing but runs smooth and pulls hard in all gears, any thoughts??

MechEng

Check your cap and rotor

Huss

they were both replaced today....still has vibration/rough idle and bad mileage

Huss

many people saying the injectors could be too. what brand to use to clean em up?

el crapitan

check for vacuum leaks

theEGGmonsta

try out the redline fuel injector cleaner or the lucas fuel full treatment. theyve both worked out well in the past

theEGGmonsta

remember that it needs fuel, compression, and spark to run properly. so theres alot of variables it can be. easiest tests you can do is fuel pressure and compression thatll rule out alot...

el crapitan

also check timing. indefinitely

Huss

Ok so Sometime when I drive the car for a Lon time turn it off
Then come back to it it takes a bit to start, at this point I really think the injectors are ****ed

el crapitan

what testing have you done to confirm that the injectors are ****ed? they aren't all that common to fail. and there are a tonne of things that could cause the same symptoms.
how long did it take to start? if the window is big enough, you can test for spark/fuel.
are you throwing any other codes?
have you checked ignition timing?

Huss

how do you check ignition timing?

i bought some injector cleaner stuff lastnight going to get a full tank and try it out.

Yes the idiot who had the car before me took the CEL bulb out, and thats how i stumbled at this problem. i went to make sure there are no codes and BAM there is like 3 codes and all of them are Cylinder 1,2,3 mis fire.

well when i went back after i replaced the Rotor/cap it was only misfire on cylinder 3. but the guy again could have screwed on how to check for more codes.

the car idles rough/vibrating in the cabin if that helps.

Huss

this might help too.

when i pulled the old plugs which were replaced in July...they all looked black and had a lot of carbon build up...so the car is running rich!


how about the intake Manifold gasket?

seanbev24

You need a timing light to check ignition timing. Also, like I said before, you need to actually confirm which cylinders are misfiring instead of relying on the codes. It could just be 1 dead cylinder. Pull plug wires or unplug injectors 1 at a time. If nothing changes with the idle on a certain cylinder, you found the problem. If the idle gets worse or it dies when you do this on every cylinder, then you actually are having random misfires on every cylinder. That information is very important.

Huss

Ok i am going to give that a try thanks! i just put some injectors cleaner in it, how long does it take to get this stuff working?

Huss

Ok so i pulled the injectors 1 by 1 and the idle dropped on all of them.

also pulled the plugs on all the cylinders and they all "spark"...


now i am really about to give up on this thing, i am running out of options here, maybe there is a sonsor that went bad? ugh....

Huss

Update: Pulled the Map sensor and the car died. so that is working also....FML......