tubeseeker

Hey folks, any insight would be great

1996 honda civic HX with a dy165 engine
under load it misfires and has gotten progressively worse
I just found a crack that goes all the way around in my exhaust manifold tonight
prior to finding this I have changed my distributor cap, ignition coil, rotor, fuel filter. Spark plugs and wires are less then one year old. I get occasional backfire as well. Until a couple of weeks agao I had decreased air flow in mymuffler and now have switched the muffler out for a straight pipe.
thanks for your time
seeker

ps. I have also checked the spark plugs and they look very good.
also, when this first started happening it was only after the car had been running for a while, 15 minutes or so, but now it happens very shortly after I get the car running. and now almost instantaneously and more severe. Is it possible that since the crack slowly expanded on the exhaust manifold the symptoms increased with that?


Modified by tubeseeker at 7:54 PM 1/13/2007

Eran

iTrader: (1)

Fix the obvious problem and then work from there.

I Shot 50 Cent

Are you asking a question? If so, what exactly is it?


Do you have any Check Engine lights? If so, have you pulled the codes to see what they mean?

8YourV8

yeah first off you gotta identify any check engine light you have. if your map or o2 sensors are acting up that can cause backfiring. but so can a number of other things. is your exhaust smoking at all? by the way replace your exhaust manifold if it's completely cracked up, thats not good. do a compression/leakdown test to make sure your runnin decently and find out if your piston rigns are alright... that can cause backfires as well as a lot of other problems that can lead to a blown motor. also, change your spark plugs. a year is more than enough time to destroy a set of spark plugs especially if you push the car real hard. and dont replace your plugs with shitty autozone Bosch plugs, buy oem or NGK plugs.

tubeseeker

The check engine light was on and it said
EGR insufficient flow
and
catalyst system efficiency below threshold.

I had the car looked at yesterday and he said he could hear it arcing and that is why I changed my coil and rotor. The light was not on today and I dont know why it was off, maybe because he cleared the codes?

I modified my original post as well to give more description

tubeseeker

Any more insight or questions into the possibilities?
thanks

nsxmatt

Your throwing a EGR and CAT code, my guess would be fix those problems first. Your also saying you have a crack in the exhaust manifold? Again, get that fixed as they crack right next to the primary o2 sensor causing bogus readings and poor running conditions.

tubeseeker

so I disconected the oxygen sensor and the symptoms stopped. So would that eliminate the possibility of the EGR being the problem?