Civic-EG.com Forum 3.3.1

- Mon May 21, 2012 1:23 pm #305630 Hey guys, I'm having trouble with my 95' LX. It's an all-stock D15b7 and the only change to the exhaust was a muffler. It all started when something started rattling in my exhaust system. It sounded like metal was clanking around inside of my cat. It would only do it at certain RPMS in which my pipe vibrated hard. I rode on it for a few weeks and finally one night when I was driving my throttle started bogging when I was give it too much gas. I headed home and it got worse and worse until I had to stop. Smoke was coming from the car and the engine was very hot. The smoke was coming from under the car and when I checked it out my cat was GLOWING hot. I got it towed to my grandparents shop and we cleaned out the cat and the noise stopped. But it still won't take a lot of gas without the throttle bogging down, and only does it when the engine is warmed up; it will run hard right after startup but won't take gas after driving for a while. I did the code reader trick and I'm honestly a little confused, it could be either 92 or 102, an electronic gas regulator valve, or a vacuum line. I did the brake dust test and it didn't shut off, so I don't think it's a vacuum line. My friend suggested getting a new cat and O2 sensors. I'm stumped, any help would be greatly appreciated.

[teal_dx]

- Mon May 21, 2012 3:49 pm #305645 if you got a code 92, then that calls for

92 Evaporative Emission Control System insufficient purge flow

I'm not sure how a bad cat could have messed up the evap purge flow valve, which is up by the intake manifold.

If your motor had an EGR valve, that would probably get damaged due to excessive exhaust being routed through it instead of the cat. However, D15b7's don't have an EGR valve. Your o2 sensor may be fouled from the ECU trying to compensate.

Replace the cat first and see how it runs.

Do Not PM me your technical questions. Post them in the forum!
My 1992 SOHC Turbo Hatch
My Youtube Channel: 6th Gear Garage

[suspendedHatch]

- Wed May 23, 2012 2:29 am #305841 Your cat would get very hot like that from running rich. It's working extremely hard. It's most likely toast. You said you "cleaned" it?!!? Other than taking a blow torch to it and gently igniting the insides, there's no way to clean it. Was the honey comb intact or is it plugged? Did a bunch of dust fall out of it?

On the firewall there's a fuel line going to the charcoal canister, and then from there to the purge solenoid on your intake manifold. Make sure everything looks right.

How's your fuel pressure? How are your injectors? Any misfires? Check the ignition and cam timing.

Don't replace that cat until you fix the fuel problem.

Also check your muffler. Take it off and make sure there isn't a bunch of rusted metal and dirt falling out of it.

- Wed May 23, 2012 2:45 am #305845 by "clean out" i think he means they hollowed it out..

- Thu May 24, 2012 1:46 pm #306066

if you got a code 92, then that calls for

92 Evaporative Emission Control System insufficient purge flow

I'm not sure how a bad cat could have messed up the evap purge flow valve, which is up by the intake manifold.

If your motor had an EGR valve, that would probably get damaged due to excessive exhaust being routed through it instead of the cat. However, D15b7's don't have an EGR valve. Your o2 sensor may be fouled from the ECU trying to compensate.

Replace the cat first and see how it runs.

Yeah that's what I found out recently. I don't even have an EGR valve! Yeah I think replacing the cat would be a good start. It kinda rattles when I hit a bump so I need to get a new one anyways. I'm ordering a high flow cat today. I'll post the results after installation. If it doesn't fix it I'll probably try getting new sensors. Thanks for the help!

- Thu May 24, 2012 2:01 pm #306068

Your cat would get very hot like that from running rich. It's working extremely hard. It's most likely toast. You said you "cleaned" it?!!? Other than taking a blow torch to it and gently igniting the insides, there's no way to clean it. Was the honey comb intact or is it plugged? Did a bunch of dust fall out of it?

On the firewall there's a fuel line going to the charcoal canister, and then from there to the purge solenoid on your intake manifold. Make sure everything looks right.

How's your fuel pressure? How are your injectors? Any misfires? Check the ignition and cam timing.

Don't replace that cat until you fix the fuel problem.

Also check your muffler. Take it off and make sure there isn't a bunch of rusted metal and dirt falling out of it.

I checked the muffler and it's in good shape. Yes like 92civic_vx said I cleaned it by hollowing it out. When I took it off dust and metal came out. It's definately toast. I'm not familiar with what a misfire is exactly(newbie) but if I give it too much gas it won't go and it will make some wierd noise. Sometimes it will act like I'm not on the gas at all. I do agree it could be a fuel line problem but I don't know where. I'm going to try a new cat and possibly new sensors and see what happens. After that I'll know it must a fuel delivery issue.

[suspendedHatch]

- Thu May 24, 2012 2:26 pm #306075 Catalytic converters don't go bad on their own. They theoretically last forever. There's a specific set of things that cause them to brick up. If you don't first fix the problem, your new cat will do the same thing within a couple dozen miles.

"High flow" cat converters are a gimmick. The only thing that matters in a cat converter is the size of the piping (and to a lesser extent, the smoothness of the transition in and out). If you ordered a "Magnaflow" cat converter, return it. They're junk. You're better off with whatever brand cat converter your local exhaust shop gives you.

Fixing a car doesn't mean getting guesses online and replacing parts. Everything on a car can be diagnosed and confirmed. You spend less money paying a competent mechanic than throwing parts at it. You could also download the Helms manual and follow the procedures.

The ECU monitors sensors and will report if they are bad. It's possible for an O2 sensor to get lazy and not throw a code, but that wont brick up a cat converter.

First fix your known problem. If you can't interpret the code you should find someone that can.

- Sun May 27, 2012 9:52 pm #306413 Clogged cat, throttle bogging down definetly running rich...like it has been said before makes no sense to put on a new cat without solving your fueling problem first

- Sun May 27, 2012 10:29 pm #306416 Check your spark plugs and see if there still good and the wires two and if it is misfireing long enough it could ruin the car the cat does not like a lot or any gas at all also check the injectors like they said up above