catalytic converter/idle problem
catalytic converter/idle problem
Will topping off the gas tank possibly cause problems for the catalytic converter? I have a '95 s14 that has had a strong smell for sometime. I took it in last May because i noticed the smell mainly when the drivers side window is down. The mechanic checked to see if any codes came up and none did. So he asked if i had been topping off and i said yes and he said not do that and see if the smell goes away after sometime. If it didn't then the catalytic converter had gotten superheated which it would need to be replaced. I never replaced it cause they were quite expensive and he didn't act like it would cause me any other problems except with an emmisions test which i passed. So I have just lived with the smell. During this time the engine has been running fine. Now 2 weeks ago I noticed that it sounded different at idle when I pulled into the garage after driving it real hard (no redlining though). It was idleing at the normal rpms and but it was louder like the fan was going faster. I noticed it today and this time the rpms were up like at 1000 and it sounded louder. So tonight i start it and let it sit and it was normal for about 30seconds then it sounded like the fan increased speed or something though the rpms were at the normal 700 but then the rpms increased to like 1000. I turned it off and it sounded different during shut down like a whining or metal to metal sound. Hard to describe. The engine does seem to pull ok, hasn't stalled and isn't burning oil. Though i am very concerned that i've damaged the engine or something bad. I hope someone has a good idea what my problems might be!'95 se w/injen intake and aftmkt plug wiresThanks
Topping off your gas wont do jack s***. You have a fuel injected engine, meaning the car's ECU is telling the fuel injectors exactly how much gas to put into the mix at each and every RPM and temperature. I think the only way to superheat a cat would be to run extremely lean, which is worse for your engine than your cat. You could easily foul up at cat if one or more of your sensors are out and you are running super duper rich (been there, done that). If you are smelling something only when the tank is full, check your gas cap. They do get old and lose their seals too.
As for your idle issue, i am assuming you do not have your A/C on, because, if so, when the compressor kicks on, it will bring the idle up to 1000 RPMs. I hope thats all it is, if its not, let me know.
As for your idle issue, i am assuming you do not have your A/C on, because, if so, when the compressor kicks on, it will bring the idle up to 1000 RPMs. I hope thats all it is, if its not, let me know.
catalytic converter/idle problem
My ac is off. It sounds like the fan is speeding up or something. Sometimes the rpms go up to 1000 and sometimes it stays normal though something sounds like it is turning on or speeding up.
As for the cat., its been a while so i don't remember exactly how the mechanic put it but it went something like this. He said since i'm topping off the extra fuel was going into the charcoal canister then getting into the intake then somehow superheating the cat.. which would burn it out eventually. He said no codes came up and there was no pre-existing codes when he pulled it up on his computer. So the engine was not running rich or lean. The maf was taking care of the mixture to keep it from running rich or lean. It went something like that. So i've let it go cause i thought if the cat was burned out it wasn't going to harm anything. At least he didn't say it would do anything. So i've just put up with the smell. The car did pass emissions which he said it probably wouldn't if the cat was bad. So i have no idea. I should have just replaced the cat and seen what would happen at least i could take it back and say i've still have the problem after replacing it but now i've got the idle problem too. The engine does seem to pull ok and its not buring oil. Though i'm concerned i may have damaged the engine or something else is really screwed. I think the gas mileage is still the same and I'm not getting any lights on the dash.
As for the cat., its been a while so i don't remember exactly how the mechanic put it but it went something like this. He said since i'm topping off the extra fuel was going into the charcoal canister then getting into the intake then somehow superheating the cat.. which would burn it out eventually. He said no codes came up and there was no pre-existing codes when he pulled it up on his computer. So the engine was not running rich or lean. The maf was taking care of the mixture to keep it from running rich or lean. It went something like that. So i've let it go cause i thought if the cat was burned out it wasn't going to harm anything. At least he didn't say it would do anything. So i've just put up with the smell. The car did pass emissions which he said it probably wouldn't if the cat was bad. So i have no idea. I should have just replaced the cat and seen what would happen at least i could take it back and say i've still have the problem after replacing it but now i've got the idle problem too. The engine does seem to pull ok and its not buring oil. Though i'm concerned i may have damaged the engine or something else is really screwed. I think the gas mileage is still the same and I'm not getting any lights on the dash.
catalytic converter/idle problem
Then how can i get a hold of drjohn. I really want to talk to someone that might have a pretty good idea. I'm pretty sure the smell is the cat. The mechanic said that when he hooked it up to his computer to check for codes none came up so there was nothing wrong how it was running..not running rich or lean. Could it still be rich or lean if it doesn't come up w/codes?
By topping off the tank you can flood the canister and this can cause a rich mixture at times. The smell might be that of rotten eggs or what is called sulfer dioxide which is a by product of combustion. This can be a sign high heat or pressure in the cylinders or a lean or rich mixture. Things to check would be the egr curcuit, timing, eng. coolant { running hot} or vac. leaks. The 02 sensors can be slow on the cross count, lean to rich and back to lean and still not cause a code.