Gas smell, cat coming out of exhaust, and misfire!

[Chris2088]

1997 3.8 camaro 5 speed

Started missing out of the blue one day while lightly accelerating. Problem disappears when I drive the car the next morning. Car drives beautifully for 4 days.

I start the car after leaving work, SES light is on, missing at idle, and misses really bad when accelerating at all. Car must be reved high to even take off without stalling out. Codes are random cyclinder misfire, my mechanics scanner shows all cyclinders are missing.

My mechanic replaces: Plugs, Wires, Ignition Control Module, Coil Packs.

Problem does NOT go away.
Yesterday in the morning I try to start car. Car wont start, eventually starts if flooring gas pedal and cranking it over for awhile. I let car idle for 10 minutes...I come out and smoke is coming out from underneath the car. Cat Converter is RED! This converter by the way is a 2 month old catco converter! It was practially new for god sake!

As of now here are the problems..

Idle: Misses/runs rough/STRONG fuel odor(especially by driver side door) Converter will turn red after about 10 minutes of idling. Car feels likes its dying, idle keeps dipping down to 600rpm and going back up to 900-1000. battery gauge lowers and lights dim accordingly.
Off the line: Misses really bad and feels likes its stalling out, unless reved to about 3,000 and slowly taken off.
Light acceleration while going down the road is okay, but if I get on it the slightest bit it misses/bogs down and does not accelerate.

This morning car also does not want to start. I floor it and it eventally starts after cranking it. Pieces of the honeycomb of my cat come out my exhaust. Fuel smell is really bad. Codes are now Cylinder 3 Misfire and Catalytic Converter Efficenicy too low. Also, EMbrake light stays on while EBrake is off.

Does anyone have any idea whats up with this car? I mean obivously my cat is done for. But isnt there a reason behind all this? Wouldnt it have to be running super rich to smell fuel and my cat to get red and all that? Whats going on?

[HossV6]

Re: Gas smell, cat coming out of exhaust, and misfire!

sounds like something happened inside your cat to block flow, bottleing all the pressure up. all the exhaust heat and pressure probably caused it to turn red and burnt up the honey comb, and thats why peices are coming out. the fuel smell... the only thing i can think of is all the pressure built up in the exhaust caused the exhaust valves to be held open and gas just passed through with out being burnt. i could be completely wrong but that is just my guess. i would have someone start your car and put your hand behind the exhaust and have them rev it so you can feel how much exhaust is flowing out. you should be able to tell if its being held up. your E brake problem im not sure about. unless some how your cat burnt up the wire or sensor when it got so hot. you will most likely need to replace the cat and probably the O2 sensor as well, im guessing its going to be shot after all the heat build. besides the guess i posted above, it could be something linked to your computer, your cars computer could have gone bad or something causing it to send too much fuel. i have seen that kind of problem with my 4 wheelers, if they were jetted too rich alot of the time the header would turn red, caused by all the extra fuel burning inside the exhaust. in your case the extra fuel is burning off inside the cat burning it up

[Chris2088]

Re: Gas smell, cat coming out of exhaust, and misfire!

Yeah, I'm wondering if my computer is telling it to send too much fuel. I know the fuel pressure at the rail is around 40-45psi. Which is supposed to be 48-55psi I hear. I just dont want to replace the cat and still have misfires that tear a new one up. If my fuel pump was going Id think it would run lean. And I wouldnt have my cat getting red hot.

[vanbibber]

Re: Gas smell, cat coming out of exhaust, and misfire!

youre probably going to need a new cat. if is turning red its probably clogged. unless the motor is dumping ALOT of fuel (which it sounds like it is) thats the only 2 reasons the cat should be turning red.

02 sensors will definately need replaced. do all of them. that may be the problem. bad o2s can wreak havoc.

[Chris2088]

Re: Gas smell, cat coming out of exhaust, and misfire!

New cat is on the way. But why is it dumping the fuel is what I'm trying to figure out. I mean if I put a new cat on and it just turns red and destroys it I'm screwed again. Also can hear a buzzing sound when accelerating coming from the rear around the fuel pump maybe?

[vanbibber]

Re: Gas smell, cat coming out of exhaust, and misfire!

fuel pump always has a sound (more like a hum, but you can hear it)

o2 sensors play a role in fueling. if theyre reading out of whack (like say theyre reading lean conditions) the pcm will detect it and start dumping fuel.

[HossV6]

Re: Gas smell, cat coming out of exhaust, and misfire!

if your worried about ruining a new cat, throw a straight pipe in place of the cat, just use a couple clamps and clamp it on, then test it out and see if it still misses, if everything is ok, replace the straight pipe with the cat. i would reccommend you check out your muffler. if it has been blowing peices of the honeycomb out, chances are there are probably some peices in the muffler you might want to get any left over peices out of the rest of the system. if your cat did get so hot that it burnt up the O2s then that is most likely why its dumping fuel. the computer isnt getting the right reading. what would happen is the O2s would register nothing because they are burnt out so that would in turn tell the computer that you arnt getting enough fuel, so its going to send more, even though you dont need it. My bet is a new cat and new O2s you will be good to go. You might have just got a deffective cat that clogged up and burnt up all your O2s. Not sure if you have emissions but i just completly removed my cat a replaced it with a short glass pack. mines a 95 so i dont have an after car O2. if you dont want to spend money on a new cat it might be something for you to consider, you would just have to get an O2 sim or tune it out, you really dont need the glass pack but it helps keep the rasp down.

[Chris2088]

Re: Gas smell, cat coming out of exhaust, and misfire!

Yeah I'm going to replace the cat and 02s. I think I might as well replace the fuel pump. The fuel pressure is now 38psi. And I can hear some pathetic buzzing sound from the rear like the fuel pump. Could it have caused my car to miss if its being weak?

[Mr. Logger]

Re: Gas smell, cat coming out of exhaust, and misfire!

Could you hear the buzzing before this happened? Just trying to determine if the fuel pump/pressure was your cause. A lean mixture burns hotter than a rich mixture.

[Chris2088]

Re: Gas smell, cat coming out of exhaust, and misfire!

A lean mixture burns hotter? So that would explain why my cat was trashed? I just started hearing it about a day after it started missing...a buzzing from the fuel pump area in the rear when accelerating...