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Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5

 
Anonymous Coward
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01/04/2017 09:36 PM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
I am fairly mechanically inclined, I do all the maintenance and repairs on my cars. I have encountered an issue that has perplexed me and was looking for more insight.

I am getting a rotten egg smell. As I have always understood it, the rotten egg smell is the result of the sulfur in the fuel contacting the platinum in the catalytic converter.

I am going to withhold a few vehicle specifics, for now, because I have been getting some automatic generic responses that the catalytic is bad and needs to be replaced. I do not buy that, however, if this continues I believe on a long enough time line it will eventually ruin the catalytic. In this case if I were to replace the catalytic, I do not feel the problem would be resolved and would still continue.

I will say that if I change who I buy the fuel from it seems to stop temporarily. It seems to resolve it for 3-4 tanks of gas then it returns. I have three different places that I cycle through buying gas from.

What could be some other things that could cause this to happen? I will say that I am forced to use premium fuel.

Sorry for the lack of vehicle information and vagueness, this is just how my bullshit detectors work.
 Quoting: BrokenTech


Its your catalytic converter
 Quoting: Anonymous Coward 69546725


Catalytic converter is almost ALWAYS the "symptom".
Anonymous Coward
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01/04/2017 09:37 PM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
Of improper fuel mixture.
Anonymous Coward
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01/04/2017 09:48 PM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
Of improper fuel mixture.
 Quoting: Anonymous Coward 73684047


Bingo
BrianBKS
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01/04/2017 10:00 PM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
could be the battery. I know when batteries go bad or leak they smell like rotten eggs.
Anonymous Coward
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01/04/2017 11:41 PM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
Fuel pressure, or your temp sender is relaying bogus data.
 Quoting: Anonymous Coward 73726185


Performance wise, the fuel pressure seems to be fine. I have not noticed any acceleration or other performance issues. I will add checking the pressure to my list to rule in/out.

Regarding the temp sender, would running a 180 degree thermostat play any role?
 Quoting: BrokenTech


Make and model, for proper diagnosis?

Could be running too warm.

 Quoting: Anonymous Coward 73726185


To warm? With a 180 degree thermostat?
 Quoting: BrokenTech


You're not getting error codes? No check engine lights???

Then it's your cat.
Anonymous Coward
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
I would say it's a bad vagina rod. Or probably worn out menstrual brushes. You probably have summer air in your radical tyres, too. I'd check the carbonator coil for combustion. Or your old lady has a yeast infraction & she leaked some fluid on your venarial seats.
BrokenTech  (OP)

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01/05/2017 12:03 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
I would say it's a bad vagina rod. Or probably worn out menstrual brushes. You probably have summer air in your radical tyres, too. I'd check the carbonator coil for combustion. Or your old lady has a yeast infraction & she leaked some fluid on your venarial seats.
 Quoting: Anonymous Coward 71002748


Damn, here I was thinking it was the canuter valve.
Anonymous Coward
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01/05/2017 12:05 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
I would say it's a bad vagina rod. Or probably worn out menstrual brushes. You probably have summer air in your radical tyres, too. I'd check the carbonator coil for combustion. Or your old lady has a yeast infraction & she leaked some fluid on your venarial seats.
 Quoting: Anonymous Coward 71002748


LOL Might as well throw those in there with all of the uninformed wild assed guesses that have been shot out so far.
BrokenTech  (OP)

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01/05/2017 12:17 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
I would say it's a bad vagina rod. Or probably worn out menstrual brushes. You probably have summer air in your radical tyres, too. I'd check the carbonator coil for combustion. Or your old lady has a yeast infraction & she leaked some fluid on your venarial seats.
 Quoting: Anonymous Coward 71002748


LOL Might as well throw those in there with all of the uninformed wild assed guesses that have been shot out so far.
 Quoting: Anonymous Coward 73706403


Hell, it could also be the tire pressure or lug nuts. Maybe even the dome light or the horn. chuckle

I swear, half the people that responded did not even comprehend the post. They felt they just needed to respond before even understanding the question. Withholding actual car specs did not seem to even help.

Last Edited by BrokenTech on 01/05/2017 12:21 AM
Anonymous Coward
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
I would say it's a bad vagina rod. Or probably worn out menstrual brushes. You probably have summer air in your radical tyres, too. I'd check the carbonator coil for combustion. Or your old lady has a yeast infraction & she leaked some fluid on your venarial seats.
 Quoting: Anonymous Coward 71002748


LOL Might as well throw those in there with all of the uninformed wild assed guesses that have been shot out so far.
 Quoting: Anonymous Coward 73706403


Hell, it could also be the tire pressure or lug nuts. Maybe even the dome light or the horn. chuckle

I swear, half the people that responded did not even comprehend the post. They felt they just needed to respond before even understanding the question. Withholding actual car specs did not seem to even help.
 Quoting: BrokenTech


It's because everyone thinks that they know something about cars, and they feel that they are smarter than the people who work on cars. While that may be true of the monkeys down at the local tire store chain, parts store chain, or department store "service department", it's a little bit more complicated and involved than just throwing out wild guesses for something you once heard someone say.

I also like "Oh, the codes tell you what's wrong now". Uh huh. Yeah, OK...

AC73684047 is the only one that I saw who was on the right track.
Anonymous Coward
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01/05/2017 12:46 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
I am not a mechanic but I have had this problem before....

Your catalytic converter is prob going bad
 Quoting: Manosteel


putin-thiss
Anonymous Coward
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
I am not a mechanic but I have had this problem before....

Your catalytic converter is prob going bad
 Quoting: Manosteel


putin-thiss
 Quoting: Anonymous Coward 73335031


You don't have enough information to accurately make that call yet. It's nothing more than a guess.

Here's the rub though - If it does indeed end up being the correct guess (after it was determined using proper diagnosis procedures by someone who actually knows what they're doing), you'd act all smug like you knew what you were talking about. You do not. Any good technician has seen that scenario play out more than once...
The Wild 0nes

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01/05/2017 01:01 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
clogged cat homie!

clogged cat can be caused by faulty bank 1 o2 sensor giving false reading causing the computer to think its running lean and dumping extra fuel. or it could be caused by either a faulty thermostat or coolant temperature sensor, which would cause the computer to do the same thing. or if its a car that utilizes a secondary air pump for emissions, a faulty solenoid would cause the vehicle to run rich, causing cat to become clogged. clogged cat can easily be checked by using a infrared temp gun to measure the temps at the front and rear of cat. if the temps are close to the same its not clogged, but if the engine side is significantly higher....bingo!

but rotten egg smell generally points to a clogged cat.
you will also notice a decrease in power, especially under load or going up steep hills. vehicle will seem to "bog" down

Problem-rotten egg smell
rotten egg smell generally points to clogged cat
Clogged cat generally caused by a rich fuel mixture condition
running rich generally caused a failure in any of sensors related to the fuel/emissions

bank 1 & 2 o2 sensors
map or maf sensor
IAT or coolant temp sensor
secondary air system
egr system

a sticking open secondary air solenoid or egr valve can cause a engine to run rich without throwing a DTC by allowing unmetered air into the exhaust system, causing bank 1 to detect a lean fuel mixture and adding fuel to compensate resulting in a unnecessary rich fuel mixture condition.

Last Edited by The Wild 0nes on 01/05/2017 01:25 AM
The first step is to establish that something is possible; then probability will occur.


It's easy to stand in the crowd but it takes courage to stand alone

Do i look really like a guy with a plan? you know what i am? I'm a dog chasing cars. I wouldn't know what to do with one if i ever caught it. You know, I.. I just do things. The mobs have plans. The cops have plans. They're Schemers. Schemer's trying to control their little worlds.

I'm Not a Schemer.
Anonymous Coward
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01/05/2017 01:17 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
clogged cat can be caused by faulty bank 1 o2 sensor giving false reading causing the computer to think its running lean and dumping extra fuel. or it could be caused by either a faulty thermostat or coolant temperature sensor, which would cause the computer to do the same thing. or if its a car that utilizes a secondary air pump for emissions, a faulty solenoid would cause the vehicle to run rich, causing cat to become clogged. clogged cat can easily be checked by using a infrared temp gun to measure the temps at the front and rear of cat. if the temps are close to the same its not clogged, but if the engine side is significantly higher....bingo!
 Quoting: The Wild 0nes


There you go!

but rotten egg smell generally points to a clogged cat.

 Quoting: The Wild 0nes



Or a rich condition. In the early stages anyway...
The Wild 0nes

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01/05/2017 01:27 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
clogged cat can be caused by faulty bank 1 o2 sensor giving false reading causing the computer to think its running lean and dumping extra fuel. or it could be caused by either a faulty thermostat or coolant temperature sensor, which would cause the computer to do the same thing. or if its a car that utilizes a secondary air pump for emissions, a faulty solenoid would cause the vehicle to run rich, causing cat to become clogged. clogged cat can easily be checked by using a infrared temp gun to measure the temps at the front and rear of cat. if the temps are close to the same its not clogged, but if the engine side is significantly higher....bingo!
 Quoting: The Wild 0nes


There you go!

but rotten egg smell generally points to a clogged cat.

 Quoting: The Wild 0nes



Or a rich condition. In the early stages anyway...
 Quoting: Anonymous Coward 73706403


i edited my post with a mini root cause analysis for dummies lol
The first step is to establish that something is possible; then probability will occur.


It's easy to stand in the crowd but it takes courage to stand alone

Do i look really like a guy with a plan? you know what i am? I'm a dog chasing cars. I wouldn't know what to do with one if i ever caught it. You know, I.. I just do things. The mobs have plans. The cops have plans. They're Schemers. Schemer's trying to control their little worlds.

I'm Not a Schemer.
Anonymous Coward
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01/05/2017 01:28 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
AC73684047 is the only one that I saw who was on the right track.
 Quoting: Anonymous Coward 73706403


Hey man, thanks!

If OP plays his cards right and gets his fuel mix corrected, he might not have to replace the cat yet.

Start with the O2 sensors, you might even have the skill to replace those yourself, if you nail down which bank it is!
Wire
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01/05/2017 01:39 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
I am giving my honest experience as a 20+ year mechanic. Typically, the only times I smell what you are describing is when I drive a car hard that has not been driven hard. I can test drive cars the same way every time but some will smell sulphury and some not. Same models, same manufacturers.

I think it's more the catalyst needs cleaned out and I am heating it up more than the customer would during their routine driving. Does this sound possible under your circumstances?
 Quoting: Anonymous Coward 73303797


Good answer!! Now that you mention it, yes. Like I stated in another post, this engine is supercharged and may be part of the reason.

Like you mentioned needing to be opened up a little more. Just put-putting around town seems to be when it is the worst. I have noticed that if I get out on the highway and open it up to 70+ mph for 40 or so miles, it seems to make a difference with the smell.
 Quoting: BrokenTech


Since you have given the most logical answer, I will reveal the vehicle specifics. Its a '01 Grand Prix GTP, not stock.

-I have replaced the supercharger pulley with a smaller one.
-Took the breather off and replaced with a K&N air filter that is not enclosed it gets all the air it wants.
-Performance wires
-Performance exhaust, cat back.
-Computer has been adjusted for the mods.

I cant remember for sure, but as I recall I did not have this problem until after I made the mods.

I tend to baby it around town. Except when some millennial pulls up next to me in their piece of shit rice burner thinking they are tough shit. They typically do not have anything for me, except when I break an axle in the process.
 Quoting: BrokenTech


Your to rich in fuel, 30 plus years with VW. Your car would never pass SMOG in Kalifornia BI YEARLY SMOG inspection. With your modified engine the only fuel you should use is Standard Oil high grade like a BMW.
Anonymous Coward
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
i edited my post with a mini root cause analysis for dummies lol
 Quoting: The Wild 0nes


You know most aren't going to do the required testing though. They're going to do the easy way. That usually goes something like one of their friends saying, "my buddy had the same exact problem and it was XXXXXX ", so that's what they replace.

Still, you gave him what he asked for though, right?

You can lead a horse to water...
Anonymous Coward
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01/05/2017 01:42 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
could be the battery. I know when batteries go bad or leak they smell like rotten eggs.
 Quoting: BrianBKS 73260361


This ^^^^

The regulator is over-charging the battery.
Anonymous Coward
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01/05/2017 01:44 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
could be a capacitor going bad
The Wild 0nes

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01/05/2017 01:44 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
i edited my post with a mini root cause analysis for dummies lol
 Quoting: The Wild 0nes


You know most aren't going to do the required testing though. They're going to do the easy way. That usually goes something like one of their friends saying, "my buddy had the same exact problem and it was XXXXXX ", so that's what they replace.

Still, you gave him what he asked for though, right?

You can lead a horse to water...
 Quoting: Anonymous Coward 73706403


sadly, thats how most mechanics fix cars now a days.
Replace until its fixed.

fuck that.
The first step is to establish that something is possible; then probability will occur.


It's easy to stand in the crowd but it takes courage to stand alone

Do i look really like a guy with a plan? you know what i am? I'm a dog chasing cars. I wouldn't know what to do with one if i ever caught it. You know, I.. I just do things. The mobs have plans. The cops have plans. They're Schemers. Schemer's trying to control their little worlds.

I'm Not a Schemer.
The Wild 0nes

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United States
01/05/2017 01:47 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
could be the battery. I know when batteries go bad or leak they smell like rotten eggs.
 Quoting: BrianBKS 73260361


This ^^^^

The regulator is over-charging the battery.
 Quoting: Chaos Replicator


na, blinker fluid is burning causing the smell. it needs changed. headlight rings must be going bad. time for a rebuild.
The first step is to establish that something is possible; then probability will occur.


It's easy to stand in the crowd but it takes courage to stand alone

Do i look really like a guy with a plan? you know what i am? I'm a dog chasing cars. I wouldn't know what to do with one if i ever caught it. You know, I.. I just do things. The mobs have plans. The cops have plans. They're Schemers. Schemer's trying to control their little worlds.

I'm Not a Schemer.
Anonymous Coward
User ID: 73706403
United States
01/05/2017 01:48 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
i edited my post with a mini root cause analysis for dummies lol
 Quoting: The Wild 0nes


You know most aren't going to do the required testing though. They're going to do the easy way. That usually goes something like one of their friends saying, "my buddy had the same exact problem and it was XXXXXX ", so that's what they replace.

Still, you gave him what he asked for though, right?

You can lead a horse to water...
 Quoting: Anonymous Coward 73706403


sadly, thats how most mechanics fix cars now a days.
Replace until its fixed.

fuck that.
 Quoting: The Wild 0nes


I know. Sadly, I think there were a few in this thread...
BrokenTech  (OP)

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01/05/2017 01:53 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
clogged cat homie!

clogged cat can be caused by faulty bank 1 o2 sensor giving false reading causing the computer to think its running lean and dumping extra fuel. or it could be caused by either a faulty thermostat or coolant temperature sensor, which would cause the computer to do the same thing. or if its a car that utilizes a secondary air pump for emissions, a faulty solenoid would cause the vehicle to run rich, causing cat to become clogged. clogged cat can easily be checked by using a infrared temp gun to measure the temps at the front and rear of cat. if the temps are close to the same its not clogged, but if the engine side is significantly higher....bingo!

but rotten egg smell generally points to a clogged cat.
you will also notice a decrease in power, especially under load or going up steep hills. vehicle will seem to "bog" down

Problem-rotten egg smell
rotten egg smell generally points to clogged cat
Clogged cat generally caused by a rich fuel mixture condition
running rich generally caused a failure in any of sensors related to the fuel/emissions

bank 1 & 2 o2 sensors
map or maf sensor
IAT or coolant temp sensor
secondary air system
egr system

a sticking open secondary air solenoid or egr valve can cause a engine to run rich without throwing a DTC by allowing unmetered air into the exhaust system, causing bank 1 to detect a lean fuel mixture and adding fuel to compensate resulting in a unnecessary rich fuel mixture condition.
 Quoting: The Wild 0nes


The car is an 01 Grand Prix GTP modded.

Its not clogged, but thats not to say it will not get that way. It has plenty of power, it still turns the wheels over at 40 mph if I put the pedal down just like it did when I originally installed the mods.

It does not always have the smell. I tend to baby it around town. As was mentioned in an earlier post about running it harder seems to help, if I get on the highway for 40 miles or so it stops for a few weeks. Changing where I get gas also makes it stop for awhile. Running it harder does indeed seem to make it go away, for awhile. When I am out tomorrow I will run the dog shit out of it and see what happens.

According to the computer, everything is still functioning fine, no fault codes. My real time OBDII software(torque pro) shows the temp as 180 degrees as it should be with a 180 degree thermostat. Short of actually doing manual checks with voltmeters and such, I am assuming the computer would alert me if something was running out of spec.

Running rich I suppose could be a possibility here if unmetered air is getting in, I will check into it.

Last Edited by BrokenTech on 01/05/2017 01:59 AM
Anonymous Coward
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01/05/2017 01:58 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
Sulphur in the gasoline.
BrokenTech  (OP)

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01/05/2017 01:58 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
AC73684047 is the only one that I saw who was on the right track.
 Quoting: Anonymous Coward 73706403


Hey man, thanks!

If OP plays his cards right and gets his fuel mix corrected, he might not have to replace the cat yet.

Start with the O2 sensors, you might even have the skill to replace those yourself, if you nail down which bank it is!
 Quoting: Anonymous Coward 73684047


I am more than capable of doing the work, I always do. I am not a pro, but I know my way around a car. This time its just throwing me for a loop. I just refuse to start throwing unnecessary parts at it hoping it fixes it. And I am trying to get to the bottom of it before I do have to replace the cat.

At this point in time, I am of the opinion its me and the car does not like how I am driving it and wants to be driven harder. Or, there is unmetered air getting in.

Last Edited by BrokenTech on 01/05/2017 02:04 AM
Anonymous Coward
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01/05/2017 02:00 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
heater core / heat diffuser leaking, passenger side under the dash
The Wild 0nes

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01/05/2017 02:01 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
clogged cat homie!

clogged cat can be caused by faulty bank 1 o2 sensor giving false reading causing the computer to think its running lean and dumping extra fuel. or it could be caused by either a faulty thermostat or coolant temperature sensor, which would cause the computer to do the same thing. or if its a car that utilizes a secondary air pump for emissions, a faulty solenoid would cause the vehicle to run rich, causing cat to become clogged. clogged cat can easily be checked by using a infrared temp gun to measure the temps at the front and rear of cat. if the temps are close to the same its not clogged, but if the engine side is significantly higher....bingo!

but rotten egg smell generally points to a clogged cat.
you will also notice a decrease in power, especially under load or going up steep hills. vehicle will seem to "bog" down

Problem-rotten egg smell
rotten egg smell generally points to clogged cat
Clogged cat generally caused by a rich fuel mixture condition
running rich generally caused a failure in any of sensors related to the fuel/emissions

bank 1 & 2 o2 sensors
map or maf sensor
IAT or coolant temp sensor
secondary air system
egr system

a sticking open secondary air solenoid or egr valve can cause a engine to run rich without throwing a DTC by allowing unmetered air into the exhaust system, causing bank 1 to detect a lean fuel mixture and adding fuel to compensate resulting in a unnecessary rich fuel mixture condition.
 Quoting: The Wild 0nes


The car is an 01 Grand Prix GTP modded.

Its not clogged, but thats not to say it will not get that way. It has plenty of power, it still turns the wheels over at 40 mph if I put the pedal down just like it did when I originally installed the mods.

It does not always have the smell. I tend to baby it around town and if I get in it a little bit it starts. As was mentioned in an earlier post about running it harder seems to help, if I get on the highway for 40 miles or so it stops for a few weeks. Changing where I get gas also makes it stop for awhile. Running it harder does indeed seem to make it go away, for awhile. When I am out tomorrow I will run the dog shit out of it and see what happens.

According to the computer, everything is still functioning fine, no fault codes. My real time OBDII software(torque pro) shows the temp as 180 degrees as it should be with a 180 degree thermostat. Short of actually doing manual checks with voltmeters and such, I am assuming the computer would alert me if something was running out of spec.

Running rich I suppose could be a possibility here if unmetered air is getting in, I will check into it.
 Quoting: BrokenTech


if bank 1 is detecting a false lean condition due to unmetered air, you'll see a big fluctuation in the reading on bank1o2 in freeze frame diagnostics. and was your pcm tune a mail order or real time tune?

*** you can also do a basic check if you have a good dtc reader. if your fuel trim is running greater than 10%, the computer is trying to compensate for something. one thing to remember here is that your car is supercharged. its better to run lean with boost than rich, so be careful running it hard until you get it straightened out. running rich with a boosted car opens up the opportunity for detonation...which is something you want to avoid like the plague.

Last Edited by The Wild 0nes on 01/05/2017 02:06 AM
The first step is to establish that something is possible; then probability will occur.


It's easy to stand in the crowd but it takes courage to stand alone

Do i look really like a guy with a plan? you know what i am? I'm a dog chasing cars. I wouldn't know what to do with one if i ever caught it. You know, I.. I just do things. The mobs have plans. The cops have plans. They're Schemers. Schemer's trying to control their little worlds.

I'm Not a Schemer.
Anonymous Coward
User ID: 73706403
United States
01/05/2017 02:02 AM
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
clogged cat homie!

clogged cat can be caused by faulty bank 1 o2 sensor giving false reading causing the computer to think its running lean and dumping extra fuel. or it could be caused by either a faulty thermostat or coolant temperature sensor, which would cause the computer to do the same thing. or if its a car that utilizes a secondary air pump for emissions, a faulty solenoid would cause the vehicle to run rich, causing cat to become clogged. clogged cat can easily be checked by using a infrared temp gun to measure the temps at the front and rear of cat. if the temps are close to the same its not clogged, but if the engine side is significantly higher....bingo!

but rotten egg smell generally points to a clogged cat.
you will also notice a decrease in power, especially under load or going up steep hills. vehicle will seem to "bog" down

Problem-rotten egg smell
rotten egg smell generally points to clogged cat
Clogged cat generally caused by a rich fuel mixture condition
running rich generally caused a failure in any of sensors related to the fuel/emissions

bank 1 & 2 o2 sensors
map or maf sensor
IAT or coolant temp sensor
secondary air system
egr system

a sticking open secondary air solenoid or egr valve can cause a engine to run rich without throwing a DTC by allowing unmetered air into the exhaust system, causing bank 1 to detect a lean fuel mixture and adding fuel to compensate resulting in a unnecessary rich fuel mixture condition.
 Quoting: The Wild 0nes


The car is an 01 Grand Prix GTP modded.

Its not clogged, but thats not to say it will not get that way. It has plenty of power, it still turns the wheels over at 40 mph if I put the pedal down just like it did when I originally installed the mods.

It does not always have the smell. I tend to baby it around town. As was mentioned in an earlier post about running it harder seems to help, if I get on the highway for 40 miles or so it stops for a few weeks. Changing where I get gas also makes it stop for awhile. Running it harder does indeed seem to make it go away, for awhile. When I am out tomorrow I will run the dog shit out of it and see what happens.

According to the computer, everything is still functioning fine, no fault codes. My real time OBDII software(torque pro) shows the temp as 180 degrees as it should be with a 180 degree thermostat. Short of actually doing manual checks with voltmeters and such, I am assuming the computer would alert me if something was running out of spec.

Running rich I suppose could be a possibility here if unmetered air is getting in, I will check into it.
 Quoting: BrokenTech


Either you're not paying attention or you don't understand.
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Re: Question for the Auto Mechanics, Rotten Egg Smell *REVISITED* Pg 5
At this point in time, I am of the opinion its me and the car does not like how I am driving it and wants to be driven harder.
 Quoting: BrokenTech


I don't even know where to start with that.

Or, there is unmetered air getting in.
 Quoting: BrokenTech


That would make it go lean until the PCM tried to correct for it. It would more than likely set a code, but not always. I'd expect hesitation especially at throttle tip in and pinging / detonation that was intermittent.





GLP