ok,I have a 96 integra ls sedan with a auto trans.
it has 185k on it (org motor and trans)

the problem: it has a rough idle,even rougher with the a/c on, it's sluggish as hell on take off. but once the rpms get over around 2500 it drives ok...

it's throwing a rear o2 sensor code ,and a cylinder #1 misfire code

new parts: coil,cap,rotor,plugs,plug wires,fuel filter,pcv valve. timing belt and water pump have around 20k on them.

I checked the timing and the intake cam is off maybe a half tooth,me and a friend messed with it for 3 hours and could not get it perfect.

i'm thinking it could be 1 of 3 things,or a combination of the 3..
timing belt could have stretched???
oem cat could be clogged???
or the ignition control module is bad???

i'm lost, any info would be greatly appreciated.

 

cloged cat or bent valve...you do a compression or leak down test yet?

 

no leak down or compression test yet.
I bought it about 3 weeks ago from a elderly couple,they have owned it since it was brand new.

It has never been drove hard or raced,so I highly doubt it has bent valves.

 

still need to start with compression test to see problem hole,
just cause the crank sensor see's a misfire in cylinder 1, doesnt mean it is cylinder 1

 

ok,I will do a comp and leak down test today.
what are the odds that it has a bad ignition control mod?

 

Nobody can or will tell you until we can confirm the mechanical condition of the engine.

 

ok I will update as soon as I finish the tests. thanks

 

i would look into that cat..if you can do a pressure test wit the engine running before the cat and another after.. it shouldnt be that much of a difference..or if you can just take the cat out and see how it runs without it..if it idles better then you know that was your problem..

 

As prolonged driving with a missfiring cylinder causes damage to the catalyst.

 

I had the same problem in my integra you need to fix the o2 sensor. If the ecu does not have the o2 sensor disable then it will try to read the sensors readings. If the sensor is bad it send wrong or no information back to the ecu which the o2 sensor will tell the ecu your running to lean or rich and your ecu will try to compensate for it there for will make the car sluggish and could cause your fuel mixture to be wrong and would cause a misfire

 

All of this ^ has zero to do with the two faults the OP has

1 Rear O2 code is simply catalyst effeciency and does not effect the way the vehicle runs at all. It is just part of the catalyst monitor used in the OBD2 protocol. remember this is an 96 integra.

2 missfire on cylinder#1,
This means there is a missfire on cylinder#1 or cylinder#4(either left or right side of the motor) This is a mechanical problem and must be fixed, hopefully its a faulty injector, or an ignition problem, and not a hardware problem. When you experience a missfire unspent fuel from that cylinder/cylinders that arent firing are reaching the catalytic converter and turning it into an incinerator which ruins the cat all together if driven along time with it missfiring.
So guess what happens when the old people drive around like that forever???
It ruins the cat, and causes O2 sensor #2(downstream) to read the catalyst effeciency being out of range. So 2 is the cause of 1 and 1 will not go away until 2 is fixed, and possibly the cat being replaced.

 

sorry it has taken so long to reply.

ok,the cat was clogged because i replaced it and drives so much better. it has alot more torque and better acceleration.
I've also fill the rear mount with polyurethane because it was trashed and the motor was trying to do backflips.
it drives and shifts like a new car but it still idles rough.

the compression was between 185-195 in all cylinders.
i went ahead and replaced the wires(ngk), plugs(ngk platinum), coil,icm,rotor and cap.,again ...

I'm stumped...

 

im wondering if i am having a similar problem with my cat,because before i rebuilt it,i had to dump the oil out of the cat and headers....ugh.
as far as your rough idle goes,clean the iacv and make sure tps is showing proper voltage.

 

if you'd performed the vacuum test like i had mentioned, it would tell you if the cat was restricted.
if the car won't maintain idle, just disconnect the cat and see if it helps

start with a power balance to confirm the specific cylinder misfire, if there is one.
if it doesn't turn out to be a dead miss, a technique to confirm a lean condition would be to fog in a shot of propane through a vac line at idle. if the idle stabilizes, engine is running lean and further testing to narrow down the culprit would be required.
it's a bit caveman, but unless you've got an oscilloscope at hand, it'll be your best bet for now. if idle doesn't stabilize, it'll be an ignition related issue.
and just so you know, that nice shiny new cat you installed is on borrowed time, since you have not corrected the cause of failure.
try the propane method. then we'll move further into it

 

im getting there man..just havent had a chance to work on the car yet.i will tomorrow.and i really appreciate the help

 

just remember to find out what's going on with the valve clearance. because if you don't have clearance, those valves will stay hung open, and it's gonna run like a sack of hammers...like it is now

 

ok i had the codes pulled again and now I'm getting :
15-Ignition output signal
65-Secondary oxygen sensor heater
71-random misfire cylinder 1
72-random misfire cylinder 2
73- random misfire cylinder 3
74-random misfire cylinder 4

I'm pretty sure codes 71,72,73,74 are caused from code 15, but what could cause it to throw code 15?

 

an oscilloscope would be so nice for this....
sooo guess your best bet here, since the vehicle still runs, is to check primary and secondary coil resistance

 

wow,
You are correct though, find the troubleshooting flowchart for code 15 in the factory service manual and start there.

 

I just checked and cleaned all the wires in the dizzy plug,engine harness and the ecu. None of the plugs or wires looked bad nor were any of them loose. There wasnt any debris in any of the plugs.
I also removed all the engine grounds and cleaned them. Also removed the battery cables and cleaned the battery post and terminals.

Re-installed everything and started it... It still idles like **** but its not throwing code 15,71,72,73 or 74 anymore... Just throwing the rear o2 sensor code.


-------------------------------------------------------
Rundown of everything thats been done or replaced:
New NGK plug wires
New NGK platinum plugs
New ignition coil
New ignition control module
New rotor
New pcv valve
Cleaned the IACV
Cleaned and adjusted the FITV
Cleaned and checked all the harness plugs and ecu wires
Removed the throttle body and cleaned it
Checked and cleaned all the grounds
Cleaned battery post and terminals
Timing belt and water pump around 40k ago
Replaced the cat
No more code 15,71,72,73,74
Still throwing code 65(rear o2 sensor)

I have no clue what to do or try now.....

 

those codes will come back. since you disconnected the battery, they've been erased. they'll take a couple drive cycles.
unfortunately, following the flow chart works for a code 15 and no start...i believe.
your best bet is checking coil resistance. and even that is still dogshit.

 

well i just went and bought (wasted more money) another brand new ignition coil,
better quality cap and rotor,new ngk plugs and a thermostat... and you were right,it started throwing codes 65,71,73,74 .
but no code 15 or 72 ???

Still has a rough idle.

what are the odds that the injectors could be bad or clogged?
a friend is going to bring me a set of known working ones and I'm going to give them a try.

 

the odds are highly unlikely, since you'd had that code 15.
it's gonna be an ignition problem, bud. but if you want to verify, just fog in a little propane in through a vacuum line. if the idle soothes out, problem is in fuel delivery.
otherwise, you're gonna need, at the very least, a DMM

 

i removed the injector clip and plug wire from cylinder 3 and there was no change in how it ran.
it tries to die when i removed the clips or wires from 1,2,4 .

#3 injector bad?

 

you know, after i'd posted last i was thinking about this and wondering how does the ecm come to the conclusion of a code 15? i mean, how does it monitor ignition input? if it's just through misfire data alone, than yes, an injector could cause the problem among other mechanical faults aside from the ignition system. i'm not sure how it detects this, but i will find out.
you can try a couple things here. easiest is to pull out #3 spark plug and see if it's fuel soaked. not very accurate though. next, you can try as i'd suggested and fog in a shot of propane into the intake and see if it smooths out briefly. if it does, i'd check injector pulse at #3 cylinder.

by fogging in the propane, at least you narrow it down to a fuel problem. and then you can move onto further testing from there.