freakville03

2000, Z24, 2.4. Broke down with my daughter so i went to pick it up and when i started it, i noticed that it has a strong smell of fuel coming out of the exhaust.

EinST

Was this smell before or after it was successfully started? Is this the same vehicle that got her stranded at McDonald's? How did that problem turn out?

freakville03

Yes this is the same car that left her at McDonald's. That issue was the shift cable came disconnected. Now this problem is tricky. I put new spark plugs in it yesterday and took it for a 10 mile journey. Everything worked great until I was half way home and then the car started to mis-fire again. Kinda at a lost. OBD II code was P0300. So after I changed the spark plugs there was no mis-fire. Then about 15 mile into the trip it started to mis-fire again. I put Bosch Plat and have them gap to factory settings of .050.

EinST

I don't know why but restrictive exhaust comes to mind. Maybe the catalytic converter is cooked and plugging up the exhaust. Unburned fuel in the exhaust can be a result of the P0300 (i.e., ignition problem) or the PCM reacting to the code by dumping fuel in an attempt to prevent engine damage which in turn, ironically, leads to catalyst damage.

freakville03

so you think that i should change the Catalytic converter? I had tried to take it to work this morning, but it started to misfire on me after it got up to normal temp. then the check engine light started blinking. took it home and took my car.

freakville03

I have to ask this question, i have no idea what you mean when you say the catalytic converter is cooked and plugging up the exhaust. Exhaust is still coming out, unless that is maintenance talk that i don't know. Can you please make it easier to understand.

EinST

The catalysts inside the catalytic converter can melt and/or disintegrate and plug up the exhaust passage. When the exhaust system can only pass so much of the gases, back pressure builds up and interferes with the engine "breathing."

Mikey Curtis

i have to agree with the odd feeling about it that freak has.... i live in FL. we dont have inspections. the 96 k1500 yukon 5.7 i have, has no cats. my buddy and i removed em, then welded a pipe (same pipe width.. no reduction). 02 sensors upstream read fine. downstreams are new. tried open loop on MAF by unplugging, checked all evap, timing is fine, oil pump and dist are fine.... before he sold it to me, he said he found a wire that he replaced (VERY WELL by the way! i cant find it) that stopped it from doing that immense amout of gas... it wasnt even just the smell.. YOU CAN SEE THE VAPOR! very freakin dangerous! would anyone happen to know what "wire" could cause this? he cant remember a bit about it. its been too long.

i had terrible mis in 4... found a cracked plug and replaced that. 2 days later, constant on 1... nothing wrong with 1.. not gunked in any way... forgot i had my B2S1 02 unplugged... plugged it back in... and now its not missing in any particular cyl! its random and on a humid night, u can just see gas vapors shooting out! i do have a small exhause leak from a bad weld spot (but thats after the B1S1). plugs and wires are new, cap, rotor, dist, fuel reg, OEM spiders, pump is clean and runs 100%, air is good, CKS and TPS are new.................. oh man, someone please tell me if this mystery wire is the issure. im not trying to get an ECM.. at that point, i know im just shooting in the dark... most of these replacements were when he owned it. i really hope someone knows SOMETHING about what my bro was talking about. lol i wish HE knew!! haha

please gimme a shout here or email me. im gonna type it weird in case this site blocks email addresses:

trashNcrashes 321 @ gmail . com

thanks in advance! and if someone points me in the right direction, I WILL POST HERE!

-Mikey

Mikey Curtis

one other thing... my hardbody had the cat melt.. it was due to me being a kid and ignoring a bad misfire for super long.. once the cat begins to clog, the mis will allow gas to explode in the manifold (instead of cyl). that creates so much more heat than the cat is ready for and melts it faster. ignoring it for about 4 months and i couldnt even start it again.. its a 5 speed; i was in 1st, my coworker drove me around the apartments we worked at, and my other coworkers husband started yelling "Stop!! IT LOOKS LIKE LAVA IS POURING OUT UNDERNEATH!"

took a sawzall to it, found out i cut just past the 4 bolts i couldve undone (18 year old me haha), changed the oil (read the PS) and worked great! just sounds like a crappy diesel with the stupid flex pipe i put on it haha!

PS
if u misfire for a long enough time, fuel WILL get into your oil and thin it! after doing that for way too long, basically your entire motor is a second gas tank with spark plugs built in... ALWAYS pay attention to the fluids! after changing that oil, i was seriously uneased. i swear i had more gas in my motor than oil!

Mikey Curtis

before it is totally plugged.. thats the smell youll get. they only clog from overheating and its really hard to melt platinum with gas. it takes a while of gas burning at the cat.. like.. a long while, before that happens.. once it does, the platinum will be caught up and melded with other minerals that oxidize very easily. the fine web of the platinum gets hit by chunks of those things... those things get heated much faster than the platinum, but eventually the entire thing will start to fall into one piece.

basically, as it begins to clog (when you cant tell at all), it PROGRESSIVELY gets worse. idk if this is what you were trying to say, but regardless, YES maintenance is 100% true way to prevent this from happening,