Smell coming out of my exhaust still.... - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

SilviaSR20DET · 11-23-2002, 02:47 AM

Ive been experiencing a wierd smell out of my exhaust when i drive hard (I have the N1 Dual). Is it becuase i need to strap that o2 ground strap to my exhaust? I have had the exhaust for a little more than a month and the smell doesnt seem to go away. People say that its the new gasket being broken in and soon the smell will go away, is this true? Please help, thank you

95civicEX · 11-23-2002, 06:39 PM

does it kindof smell like marshmallows? if so that will go away eventually.

Nerfdude · 11-24-2002, 01:31 PM

does it smell like rotting fish in the sun? that'll go away eventually.

**mrmephistopheles** · 11-25-2002, 12:18 AM

95civicEX and Nerfdude: har har. yuo arr teh funnay. In other words, if you don't have anything useful to add to an honest question in a technical forum, don't waste any of our collective bandwidth by cluttering it with BS.

SilviaSR20DET: When complaining about an exhaust smell, it helps to describe it. It may well be the inner lining of the exhaust burning away, as well as the gaskets being scorched. This is normal for all new exhausts and it will go away.

However, I HIGHLY recommend reattaching that ground strap. Nissan electrical systems are very touchy. If you want to experiment, disconnect a ground or two inside your engine bay and see what happens.
Improper electrical readings from your 02 sensor can cause anything to a lean or rich fuel situation (more commonly rich to prevent detonation). This means more fuel is dumped into the combustion chamber, some of which isn't being burned, and is having to be passed through your cat, potentially clogging it with carbon.

Who knows? Maybe your cat is burnt through.
Reattach that ground strap, and give the exhaust about 2 weeks to break in. Let me know what happens.

Kevin

NichiSan · 11-25-2002, 09:57 AM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (mrmephistopheles @ Nov. 25 2002,01:18)</td></tr><tr><td id="QUOTE">95civicEX and Nerfdude: har har. yuo arr teh funnay. In other words, if you don't have anything useful to add to an honest question in a technical forum, don't waste any of our collective bandwidth by cluttering it with BS.

SilviaSR20DET: When complaining about an exhaust smell, it helps to describe it. It may well be the inner lining of the exhaust burning away, as well as the gaskets being scorched. This is normal for all new exhausts and it will go away.

However, I HIGHLY recommend reattaching that ground strap. Nissan electrical systems are very touchy. If you want to experiment, disconnect a ground or two inside your engine bay and see what happens.
Improper electrical readings from your 02 sensor can cause anything to a lean or rich fuel situation (more commonly rich to prevent detonation). This means more fuel is dumped into the combustion chamber, some of which isn't being burned, and is having to be passed through your cat, potentially clogging it with carbon.

Who knows? Maybe your cat is burnt through.
Reattach that ground strap, and give the exhaust about 2 weeks to break in. Let me know what happens.

Kevin</td></tr></table><span id='postcolor'>
excellent answer!

I don't have a new exhaust, I have the smell, though. I had an exhaust leak and I thought that this was causing it, and I fixed the exhaust leak, but the smell is still there. I cann't desribe the smell any better than saying that it suggests to me un-burnt fuel. It's the type of exhaust smell that you can feel when standing near an old bus that is letting out a lot of smoke.

I think it may be the cat. I don't know.

questions:

1. can I take out the cat and CLEAN it? (not replace it) - HOW? how difficult it is?

2. could you give more details regarding the ground thing? What connection, where is it?

thanks

wpayne · 11-25-2002, 12:10 PM

Is there any smoke that comes out from hard driving?

Is the smell sweet in a way? I could possibly be coolant being burnt (i just found this out). If you have a leak in your headgasket then it could be coolant seeping in and being burnt. You wanna get this checked right away if this is happening. Usually theres is some white smoke if this happens.

NichiSan · 11-25-2002, 02:43 PM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (wpayne @ Nov. 25 2002,1:10)</td></tr><tr><td id="QUOTE">Is there any smoke that comes out from hard driving?

Is the smell sweet in a way? I could possibly be coolant being burnt (i just found this out). If you have a leak in your headgasket then it could be coolant seeping in and being burnt. You wanna get this checked right away if this is happening. Usually theres is some white smoke if this happens.</td></tr></table><span id='postcolor'>
no white smoke, no sweet odor. Just thick, cough-producing  exhaust smell. That's why I figured it's the cat. Again, can I clean it?

thanks

180cruiser · 11-25-2002, 05:06 PM

Very possibly it is your cat.  I had that problem when I had mt sr20det and it was running rich.  After a few months of running rich I started smelling that strong odor.  Performance also declined.  Turned out my cat was melted half way through.  The smell was unburned fuel that the cat wasn't burning up.  You can take your car to a muffler shop and they can test your cat to see if that is the problem.  They usually do the test for free.

NichiSan · 11-26-2002, 08:00 AM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (180cruiser @ Nov. 25 2002,6:06)</td></tr><tr><td id="QUOTE">Very possibly it is your cat. I had that problem when I had mt sr20det and it was running rich. After a few months of running rich I started smelling that strong odor. Performance also declined. Turned out my cat was melted half way through. The smell was unburned fuel that the cat wasn't burning up. You can take your car to a muffler shop and they can test your cat to see if that is the problem. They usually do the test for free.</td></tr></table><span id='postcolor'>
thanks!

can I clean the cat or do I have to change it? I would prefer to clean it if possible.

thanks

ridebmx · 11-26-2002, 09:02 AM

after i knocked out my cat, my exaust has a smell to it, but not any of the smells people tried to explain, other cars ive had with no cat have the same kinda smell, sometimes stronger at times, as long as u aren't buring coolant or oil i wouldn't worry about it, but thats me...and man those people that drive their cars that smell like rotten eggs.....fix that shit, nothing worse then getting stuck behind one of those cars, kinda makes you want to run them off the road, OT..or howa bout someone that just hit a skunk, and they are dragging it and you get stuck behind them, the joys of living in a small wooded town, also have to love all the road kill every 4 to 5 miles, yummy smells while driving...haha...

180cruiser · 11-26-2002, 05:43 PM

Well, I've never heard of cleaning a cat.  Some people gut the core out for supposedly a "high-flow" effect, but you might as well take out the cat completely.  If the core is melted like mine was the only thing you can do is replace it.

**mrmephistopheles** · 11-26-2002, 10:04 PM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (NichiSan @ Nov. 25 2002,08:57)</td></tr><tr><td id="QUOTE">I don't have a new exhaust, I have the smell, though. I had an exhaust leak and I thought that this was causing it, and I fixed the exhaust leak, but the smell is still there. I cann't desribe the smell any better than saying that it suggests to me un-burnt fuel. It's the type of exhaust smell that you can feel when standing near an old bus that is letting out a lot of smoke.

I think it may be the cat. I don't know.

questions:

1. can I take out the cat and CLEAN it? (not replace it) - HOW? how difficult it is?

2. could you give more details regarding the ground thing? What connection, where is it?

thanks</td></tr></table><span id='postcolor'>
An unburnt fuel smell suggests running rich, not a bad cat. In regards to the possibility of cleaning the cat, i'm thinking no. In CA, used cats are considered hazardous waste and are typically the first things to come off of junkyard cars to be disposed of. (most of the junkyards I go to anyway). Running rich can be caused by any number of things, but it's usually best to check these things first: 02 sensor, MAFS (especially on S13s, they tend to need a grounding strap), and ignition system (plugs, wires, etc).
As far as grounds go, look over your whole drivetrain and find all the grounds. There are a few between the motor and chassis, between the exhaust and chassis, etc. You want to make sure they're ALL connected, and that the connections are clean (free of dirt, etc). No S13s or S14s I've seen have a ground on the 02 sensor, since the metal to metal contact it has with the exhaust is sufficient for grounding, but there's always at least one ground strap connecting the exhaust and chassis.

Kevin

NichiSan · 11-27-2002, 11:39 AM

Thanks, Kevin. THat's very helpful.

thanks.

95civicEX · 11-27-2002, 02:48 PM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (mrmephistopheles @ Nov. 25 2002,01:18)</td></tr><tr><td id="QUOTE">95civicEX and Nerfdude: har har. yuo arr teh funnay. In other words, if you don't have anything useful to add to an honest question in a technical forum, don't waste any of our collective bandwidth by cluttering it with BS.</td></tr></table><span id='postcolor'>
harhar it wasn't bs  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sarcasm.gif" border="0" valign="absmiddle" alt=':sarcasm:'>  when I put on my n1 I had that scent of 'burnt marshmallows' for nearly a month before it finally went away...I was giving input, not a jackass remark...

11-25-2002, 12:10 PM	#6
wpayne Zilvia Junkie Join Date: Aug 2002 Location: Okinawa, Japan + Azusa, CA Posts: 563 Trader Rating: (0) Feedback Score: 0 reviews	Is there any smoke that comes out from hard driving? Is the smell sweet in a way? I could possibly be coolant being burnt (i just found this out). If you have a leak in your headgasket then it could be coolant seeping in and being burnt. You wanna get this checked right away if this is happening. Usually theres is some white smoke if this happens. __________________ Too many people use cars as an extension of their PENIS and they make me sick. A car is to get you from point A to point B or for motorsports. Not revving around town at stop lights. Check out my mods!: 50,000watt super amp and JDM lights!! Yeah right... S13 Silvia K's I got for free (I'm in japan now)!! Woot woot! '99 25GT-T Skyline (I don't want to list all the parts) http://welcome.to/skylinegtr '92 240sx HB

11-26-2002, 09:02 AM	#10
ridebmx Zilvia Junkie Join Date: Mar 2002 Location: Michigan Age: 41 Posts: 379 Trader Rating: (0) Feedback Score: 0 reviews	after i knocked out my cat, my exaust has a smell to it, but not any of the smells people tried to explain, other cars ive had with no cat have the same kinda smell, sometimes stronger at times, as long as u aren't buring coolant or oil i wouldn't worry about it, but thats me...and man those people that drive their cars that smell like rotten eggs.....fix that shit, nothing worse then getting stuck behind one of those cars, kinda makes you want to run them off the road, OT..or howa bout someone that just hit a skunk, and they are dragging it and you get stuck behind them, the joys of living in a small wooded town, also have to love all the road kill every 4 to 5 miles, yummy smells while driving...haha... __________________ I like my car, you may not...You like your car, I may not...To each there own, right? waiting for the sunken look to be cool..lol

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11-23-2002, 02:47 AM	#1
SilviaSR20DET Zilvia FREAK! Join Date: Mar 2002 Location: Seattle, WA Posts: 1,221 Trader Rating: (9) Feedback Score: 9 reviews	Ive been experiencing a wierd smell out of my exhaust when i drive hard (I have the N1 Dual). Is it becuase i need to strap that o2 ground strap to my exhaust? I have had the exhaust for a little more than a month and the smell doesnt seem to go away. People say that its the new gasket being broken in and soon the smell will go away, is this true? Please help, thank you

11-23-2002, 06:39 PM	#2
95civicEX Zilvia Member Join Date: Jun 2002 Location: Silver Spring, MD Age: 42 Posts: 196 Trader Rating: (0) Feedback Score: 0 reviews	does it kindof smell like marshmallows? if so that will go away eventually.

11-24-2002, 01:31 PM	#3
Nerfdude BANNED Join Date: Jul 2002 Posts: 495 Trader Rating: (0) Feedback Score: 0 reviews	does it smell like rotting fish in the sun? that'll go away eventually.

11-25-2002, 12:18 AM	#4
mrmephistopheles Magnanimous Justice Distribution Service Join Date: Mar 2002 Location: BFE Age: 23 Posts: 14,372 Trader Rating: (9) Rides Gallery: mrmephistopheles Feedback Score: 9 reviews	95civicEX and Nerfdude: har har. yuo arr teh funnay. In other words, if you don't have anything useful to add to an honest question in a technical forum, don't waste any of our collective bandwidth by cluttering it with BS. SilviaSR20DET: When complaining about an exhaust smell, it helps to describe it. It may well be the inner lining of the exhaust burning away, as well as the gaskets being scorched. This is normal for all new exhausts and it will go away. However, I HIGHLY recommend reattaching that ground strap. Nissan electrical systems are very touchy. If you want to experiment, disconnect a ground or two inside your engine bay and see what happens. Improper electrical readings from your 02 sensor can cause anything to a lean or rich fuel situation (more commonly rich to prevent detonation). This means more fuel is dumped into the combustion chamber, some of which isn't being burned, and is having to be passed through your cat, potentially clogging it with carbon. Who knows? Maybe your cat is burnt through. Reattach that ground strap, and give the exhaust about 2 weeks to break in. Let me know what happens. Kevin

11-25-2002, 09:57 AM	#5
NichiSan Join Date: Jun 2002 Posts: 33 Trader Rating: (0) Feedback Score: 0 reviews	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (mrmephistopheles @ Nov. 25 2002,01:18)</td></tr><tr><td id="QUOTE">95civicEX and Nerfdude: har har. yuo arr teh funnay. In other words, if you don't have anything useful to add to an honest question in a technical forum, don't waste any of our collective bandwidth by cluttering it with BS. SilviaSR20DET: When complaining about an exhaust smell, it helps to describe it. It may well be the inner lining of the exhaust burning away, as well as the gaskets being scorched. This is normal for all new exhausts and it will go away. However, I HIGHLY recommend reattaching that ground strap. Nissan electrical systems are very touchy. If you want to experiment, disconnect a ground or two inside your engine bay and see what happens. Improper electrical readings from your 02 sensor can cause anything to a lean or rich fuel situation (more commonly rich to prevent detonation). This means more fuel is dumped into the combustion chamber, some of which isn't being burned, and is having to be passed through your cat, potentially clogging it with carbon. Who knows? Maybe your cat is burnt through. Reattach that ground strap, and give the exhaust about 2 weeks to break in. Let me know what happens. Kevin</td></tr></table><span id='postcolor'> excellent answer! I don't have a new exhaust, I have the smell, though. I had an exhaust leak and I thought that this was causing it, and I fixed the exhaust leak, but the smell is still there. I cann't desribe the smell any better than saying that it suggests to me un-burnt fuel. It's the type of exhaust smell that you can feel when standing near an old bus that is letting out a lot of smoke. I think it may be the cat. I don't know. questions: 1. can I take out the cat and CLEAN it? (not replace it) - HOW? how difficult it is? 2. could you give more details regarding the ground thing? What connection, where is it? thanks

11-25-2002, 02:43 PM	#7
NichiSan Join Date: Jun 2002 Posts: 33 Trader Rating: (0) Feedback Score: 0 reviews	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (wpayne @ Nov. 25 2002,1:10)</td></tr><tr><td id="QUOTE">Is there any smoke that comes out from hard driving? Is the smell sweet in a way? I could possibly be coolant being burnt (i just found this out). If you have a leak in your headgasket then it could be coolant seeping in and being burnt. You wanna get this checked right away if this is happening. Usually theres is some white smoke if this happens.</td></tr></table><span id='postcolor'> no white smoke, no sweet odor. Just thick, cough-producing  exhaust smell. That's why I figured it's the cat. Again, can I clean it? thanks

11-25-2002, 05:06 PM	#8
180cruiser Join Date: Oct 2002 Posts: 13 Trader Rating: (1) Feedback Score: 1 reviews	Very possibly it is your cat.  I had that problem when I had mt sr20det and it was running rich.  After a few months of running rich I started smelling that strong odor.  Performance also declined.  Turned out my cat was melted half way through.  The smell was unburned fuel that the cat wasn't burning up.  You can take your car to a muffler shop and they can test your cat to see if that is the problem.  They usually do the test for free.

11-26-2002, 08:00 AM	#9
NichiSan Join Date: Jun 2002 Posts: 33 Trader Rating: (0) Feedback Score: 0 reviews	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (180cruiser @ Nov. 25 2002,6:06)</td></tr><tr><td id="QUOTE">Very possibly it is your cat. I had that problem when I had mt sr20det and it was running rich. After a few months of running rich I started smelling that strong odor. Performance also declined. Turned out my cat was melted half way through. The smell was unburned fuel that the cat wasn't burning up. You can take your car to a muffler shop and they can test your cat to see if that is the problem. They usually do the test for free.</td></tr></table><span id='postcolor'> thanks! can I clean the cat or do I have to change it? I would prefer to clean it if possible. thanks

11-26-2002, 05:43 PM	#11
180cruiser Join Date: Oct 2002 Posts: 13 Trader Rating: (1) Feedback Score: 1 reviews	Well, I've never heard of cleaning a cat.  Some people gut the core out for supposedly a "high-flow" effect, but you might as well take out the cat completely.  If the core is melted like mine was the only thing you can do is replace it.

11-26-2002, 10:04 PM	#12
mrmephistopheles Magnanimous Justice Distribution Service Join Date: Mar 2002 Location: BFE Age: 23 Posts: 14,372 Trader Rating: (9) Rides Gallery: mrmephistopheles Feedback Score: 9 reviews	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (NichiSan @ Nov. 25 2002,08:57)</td></tr><tr><td id="QUOTE">I don't have a new exhaust, I have the smell, though. I had an exhaust leak and I thought that this was causing it, and I fixed the exhaust leak, but the smell is still there. I cann't desribe the smell any better than saying that it suggests to me un-burnt fuel. It's the type of exhaust smell that you can feel when standing near an old bus that is letting out a lot of smoke. I think it may be the cat. I don't know. questions: 1. can I take out the cat and CLEAN it? (not replace it) - HOW? how difficult it is? 2. could you give more details regarding the ground thing? What connection, where is it? thanks</td></tr></table><span id='postcolor'> An unburnt fuel smell suggests running rich, not a bad cat. In regards to the possibility of cleaning the cat, i'm thinking no. In CA, used cats are considered hazardous waste and are typically the first things to come off of junkyard cars to be disposed of. (most of the junkyards I go to anyway). Running rich can be caused by any number of things, but it's usually best to check these things first: 02 sensor, MAFS (especially on S13s, they tend to need a grounding strap), and ignition system (plugs, wires, etc). As far as grounds go, look over your whole drivetrain and find all the grounds. There are a few between the motor and chassis, between the exhaust and chassis, etc. You want to make sure they're ALL connected, and that the connections are clean (free of dirt, etc). No S13s or S14s I've seen have a ground on the 02 sensor, since the metal to metal contact it has with the exhaust is sufficient for grounding, but there's always at least one ground strap connecting the exhaust and chassis. Kevin

11-27-2002, 11:39 AM	#13
NichiSan Join Date: Jun 2002 Posts: 33 Trader Rating: (0) Feedback Score: 0 reviews	Thanks, Kevin. THat's very helpful. thanks.

11-27-2002, 02:48 PM	#14
95civicEX Zilvia Member Join Date: Jun 2002 Location: Silver Spring, MD Age: 42 Posts: 196 Trader Rating: (0) Feedback Score: 0 reviews	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (mrmephistopheles @ Nov. 25 2002,01:18)</td></tr><tr><td id="QUOTE">95civicEX and Nerfdude: har har. yuo arr teh funnay. In other words, if you don't have anything useful to add to an honest question in a technical forum, don't waste any of our collective bandwidth by cluttering it with BS.</td></tr></table><span id='postcolor'> harhar it wasn't bs  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sarcasm.gif" border="0" valign="absmiddle" alt=':sarcasm:'>  when I put on my n1 I had that scent of 'burnt marshmallows' for nearly a month before it finally went away...I was giving input, not a jackass remark...