Exhaust Smell

liberty2.8 · **Posted:** Fri Dec 05, 2008 2:04 pm

Quote:

Noticed that the exhaust from the CRD smells a bit more toxic than usual. Left it idling a few minutes and it seemed a bit like a gasoline engine
running with the choke on. Fuel was from a high volume 76 dealer with the lowest price in the state at the time ($3.75). The last time I remember really bad diesel exhaust was when I filled the Mercedes with Tesoro diesel.

Did you ever get a good answer to your question? Mine has different smell than normal diesel exhaust too. I was thinking about what an earlier post suggested... gutting the cat. Have you thought about that and what is the easiest way to do that. I'd rather straight pipe it though.

Wobbly · **Posted:** Sat Dec 06, 2008 10:10 am

liberty2.8 wrote:

Quote:

Noticed that the exhaust from the CRD smells a bit more toxic than usual. Left it idling a few minutes and it seemed a bit like a gasoline engine
running with the choke on. Fuel was from a high volume 76 dealer with the lowest price in the state at the time ($3.75). The last time I remember really bad diesel exhaust was when I filled the Mercedes with Tesoro diesel.

Did you ever get a good answer to your question? Mine has different smell than normal diesel exhaust too. I was thinking about what an earlier post suggested... gutting the cat. Have you thought about that and what is the easiest way to do that. I'd rather straight pipe it though.

This thread for Ford Powerstrokes points the finger at the cat and/or the fuel: http://www.thedieselstop.com/forums/f35 ... ndex2.html

DOC4444 · **Posted:** Sat Dec 06, 2008 11:32 am

2005 CRD

CAT was cleaned out and Magnaflow (standard 2.5") exhaust was added at the same time at about 40K. Noteable diesel exhaust smell was immediately apparent when coming to a halt and immediately exiting the vehicle, where none had been present, previously. The OEM system has a downturned tip. but I doubt that would be a big factor.

(We had been running InMotion ECU for some time, prior to exhaust change.)

So, my experience is MUCH more odor after CAT "cleaning".

However, people seem to be complaining about something somewhat different from a standard "diesel exhaust" smell with CAT intact. That makes me wonder if perhaps an overly rich mixture, coolant in exhaust, etc, may be the culprit since our's was virtually "scent free" of any type with OEM CAT intact.

DOC

nursecosmo · **Posted:** Sat Dec 06, 2008 12:54 pm

DOC4444 wrote:

2005 CRD

CAT was cleaned out and Magnaflow (standard 2.5") exhaust was added at the same time at about 40K. Noteable diesel exhaust smell was immediately apparent when coming to a halt and immediately exiting the vehicle, where none had been present, previously. The OEM system has a downturned tip. but I doubt that would be a big factor.

(We had been running InMotion ECU for some time, prior to exhaust change.)

So, my experience is MUCH more odor after CAT "cleaning".

However, people seem to be complaining about something somewhat different from a standard "diesel exhaust" smell with CAT intact. That makes me wonder if perhaps an overly rich mixture, coolant in exhaust, etc, may be the culprit since our's was virtually "scent free" of any type with OEM CAT intact.

DOC

The normal "diesel" smell is not bothersome, in fact it smells good to me. The smell which comes out of the cat is not as strong of an odor but makes the eyes sting and is somewhat similar to vinegar.

gmctd · **Posted:** Sat Dec 06, 2008 2:41 pm

The soot trap is just that: the ceramic honeycomb matrix is designed to trap the heavier particulates, known as soot, resulting from Diesel fuel combustion - occuring continuously and not even harmless, soot can be rendered more harmless by baking it into ash, also not environmentally friendly, but better than raw black soot - soot collects in the matrix at all loads, speeds and rpms, but tends to accumulate in increasing amounts at lower speeds where Exhaust Gas Temperatures are low and the matrix is cool - at higher EGT's, like from highway speeds, the ceramic matrix will heat up to temperatures which will burn soot into ash, which will then waft into the environment as much less noticeable ash-colored ash - the longer the periods when EGT's can be kept high, the more efficient the soot trap is - this means that a KJ CRD driven mainly in slow traffic day by day and seeing little hiway use will have a very contaminated soot trap, and will require longer hi-EGT runs to clear that increased accumulation - long idle periods will not clear it up or reduce the odor

Now - cool\cold fall\winter\spring temps only serve to aggravate that condition, as cold-starts require advanced injection timing and increased idle fuelrates until Engine Coolant Temperatures rise above ~85-125*F = even more soot accumulation, with increasingly acrid exhaust fumes emanating from that sooty trap - add to that #1 Diesel fuel, formulated with even lower btu-content for cold temperatures and distributed at beginning of cold weather, for more noticeable fumes - also, if you haven't winter-serviced your air filter, dirtied up during the warm-weather months, a clogged air filter further increases the fuel\air ratio, making cold-starts a crime in that white winter wonderland

nursecosmo · **Posted:** Sat Dec 06, 2008 3:48 pm

gmctd wrote:

The soot trap is just that: the ceramic honeycomb matrix is designed to trap the heavier particulates, known as soot, resulting from Diesel fuel combustion - occuring continuously and not even harmless, soot can be rendered more harmless by baking it into ash, also not environmentally friendly, but better than raw black soot - soot collects in the matrix at all loads, speeds and rpms, but tends to accumulate in increasing amounts at lower speeds where Exhaust Gas Temperatures are low and the matrix is cool - at higher EGT's, like from highway speeds, the ceramic matrix will heat up to temperatures which will burn soot into ash, which will then waft into the environment as much less noticeable ash-colored ash - the longer the periods when EGT's can be kept high, the more efficient the soot trap is - this means that a KJ CRD driven mainly in slow traffic day by day and seeing little hiway use will have a very contaminated soot trap, and will require longer hi-EGT runs to clear that increased accumulation - long idle periods will not clear it up or reduce the odor

Now - cool\cold fall\winter\spring temps only serve to aggravate that condition, as cold-starts require advanced injection timing and increased idle fuelrates until Engine Coolant Temperatures rise above ~85-125*F = even more soot accumulation, with increasingly acrid exhaust fumes emanating from that sooty trap - add to that #1 Diesel fuel, formulated with even lower btu-content for cold temperatures and distributed at beginning of cold weather, for more noticeable fumes - also, if you haven't winter-serviced your air filter, dirtied up during the warm-weather months, a clogged air filter further increases the fuel\air ratio, making cold-starts a crime in that white winter wonderland

We don't have a soot trap in the KJ.
What we have is an Oxidative Catalytic converter. It does NOT trap soot, but rather helps unburnt hydrocarbons to finish burning. What you are refering to is a DPF (Diesel particulate filter). This unit actually traps soot in a very fine ceramic matrix and when additional fuel is added (the so-called "after burner" injection event) it heats up to very high temps and burns off the trapped soot. This system which is curently used on Duramax, Powerstroke and Cummins trucks does not have to be going down the highway in order for it to kick in. There are two sensors which sense the pressure differential across the DPF and when they feel that it is becoming clogged the ECU activates the extra fueling event (it can do it at idle just fine). Of course as you mention GM, the filter will plug faster with start and stop or short trip driving.

tulsa · **Posted:** Sun Dec 07, 2008 11:23 am

For the last few weeks my CRD has had that unpleasant chemical smell from the exhaust. It had gone away when using the ORM for over a year. I took it in last week to have the rear differential speed sensor replaced for the 6th or 7th time and was told I had a MAF error. I assumed it was a P0201 told them not to worry. Got it home and the code showed as P0102 on my scangage and Advance Auto's reader. The Jeep dealers tool showed it as a P0100. Called Friday and was told they were waiting on a "throttle control valve" to be sent from Michigan. I asked the mechanic if the part was also called the flow control valve and was told that it was the throttle control valve. Will find out more this week. I am willing to bet the FCV has been the source of the odd smell.
Lewis

Joe Romas · **Posted:** Sun Dec 07, 2008 11:52 am

nursecosmo wrote:

What you are refering to is a DPF (Diesel particulate filter). This unit actually traps soot in a very fine ceramic matrix and when additional fuel is added (the so-called "after burner" injection event) it heats up to very high temps and burns off the trapped soot. This system which is curently used on Duramax, Powerstroke and Cummins trucks does not have to be going down the highway in order for it to kick in. There are two sensors which sense the pressure differential across the DPF and when they feel that it is becoming clogged the ECU activates the extra fueling event (it can do it at idle just fine). Of course as you mention GM, the filter will plug faster with start and stop or short trip driving.

The first 96 Passat tdi diesels also had this 5th injector system. It had a built in mosketo fogging "feature". You would be stopped at a light with a police officer behind you or traveling on the interstate and suddenly you had a James Bond smoae screen behing you :roll:

They had a update where they replace the ecm and the multi opening injectors.

Goglio704 · **Posted:** Sun Dec 07, 2008 12:05 pm

tulsa wrote:

For the last few weeks my CRD has had that unpleasant chemical smell from the exhaust. It had gone away when using the ORM for over a year. I took it in last week to have the rear differential speed sensor replaced for the 6th or 7th time and was told I had a MAF error. I assumed it was a P0201 told them not to worry. Got it home and the code showed as P0102 on my scangage and Advance Auto's reader. The Jeep dealers tool showed it as a P0100. Called Friday and was told they were waiting on a "throttle control valve" to be sent from Michigan. I asked the mechanic if the part was also called the flow control valve and was told that it was the throttle control valve. Will find out more this week. I am willing to bet the FCV has been the source of the odd smell.
Lewis

The service manual refers to the part as the EGR Flow Control Valve. Dealer mechanics usually refer to it as a throttle valve because the Mopar parts system uses that terminology. Nothing helps technical work quite as much as two different sets of terminology with no guide to translate. Just one of 10,000 reasons dealers have had problems servicing the CRD.

liberty2.8 · **Posted:** Sun Jan 18, 2009 9:16 pm

Quote:

For the last few weeks my CRD has had that unpleasant chemical smell from the exhaust. It had gone away when using the ORM for over a year. I took it in last week to have the rear differential speed sensor replaced for the 6th or 7th time and was told I had a MAF error. I assumed it was a P0201 told them not to worry. Got it home and the code showed as P0102 on my scangage and Advance Auto's reader. The Jeep dealers tool showed it as a P0100. Called Friday and was told they were waiting on a "throttle control valve" to be sent from Michigan. I asked the mechanic if the part was also called the flow control valve and was told that it was the throttle control valve. Will find out more this week. I am willing to bet the FCV has been the source of the odd smell.
Lewis

Lewis, what is the latest on the chemical smell after the replacement of the FCV. I still have that odd smell and miss the good old diesel exhaust smell from my Powerstroke. Will gutting the cat help with this or not and what is the best way to do this?

liberty2.8 · **Posted:** Thu Jan 22, 2009 4:25 pm

Quote:

Quote:
For the last few weeks my CRD has had that unpleasant chemical smell from the exhaust. It had gone away when using the ORM for over a year. I took it in last week to have the rear differential speed sensor replaced for the 6th or 7th time and was told I had a MAF error. I assumed it was a P0201 told them not to worry. Got it home and the code showed as P0102 on my scangage and Advance Auto's reader. The Jeep dealers tool showed it as a P0100. Called Friday and was told they were waiting on a "throttle control valve" to be sent from Michigan. I asked the mechanic if the part was also called the flow control valve and was told that it was the throttle control valve. Will find out more this week. I am willing to bet the FCV has been the source of the odd smell.
Lewis

Lewis, what is the latest on the chemical smell after the replacement of the FCV. I still have that odd smell and miss the good old diesel exhaust smell from my Powerstroke. Will gutting the cat help with this or not and what is the best way to do this?

Bump... to anyone?

TDI4BY · **Joined:** Sun Apr 02, 2006 11:56 pm **Posts:** 644

If you remove the Kitty it will in fact smell like a real diesel again. I hate the Propane weird smell.... :shock:

liberty2.8 · **Posted:** Tue Jan 27, 2009 12:12 pm

Quote:

If you remove the Kitty it will in fact smell like a real diesel again. I hate the Propane weird smell

That's what I was hoping to hear. Instead of removing the kitty, I thought of simply gutting the kitty. What is the best way to accomplish that? Didn't seem to be an easy way to remove or accomplish while still installed.

BlackLibertyCRD · **Posted:** Tue Jan 27, 2009 2:59 pm

unbolt the muffler from the cat and break the honeycone up with rebar. start the engine and blow out the debries then bolt the muffler up.

TDI4BY · **Joined:** Sun Apr 02, 2006 11:56 pm **Posts:** 644

BlackLibertyCRD wrote:

unbolt the muffler from the cat and break the honeycone up with rebar. start the engine and blow out the debries then bolt the muffler up.

At least that's what "your friend" did right. :lol:

liberty2.8 · **Posted:** Wed Jan 28, 2009 5:06 pm

Quote:

unbolt the muffler from the cat and break the honeycone up with rebar. start the engine and blow out the debries then bolt the muffler up.

so... has anybody here actually done this? It sounds easy in theory but how can you ensure you got all the honeycomb out.
From what I can tell, there isn't much room under there to insert a long tool or piece of rebar.

BlackLibertyCRD · **Posted:** Wed Jan 28, 2009 5:25 pm

There is plenty of room, sometimes there is divider screen in the middle. I only hollowed them out if it clogged or gone bad. Otherwise I don't think of much benefits.

nursecosmo · **Posted:** Wed Jan 28, 2009 9:41 pm

liberty2.8 wrote:

Quote:

unbolt the muffler from the cat and break the honeycone up with rebar. start the engine and blow out the debries then bolt the muffler up.

so... has anybody here actually done this? It sounds easy in theory but how can you ensure you got all the honeycomb out.
From what I can tell, there isn't much room under there to insert a long tool or piece of rebar.

Done it. The material which the honeycomb is made from is very hard, so it took a lot of banging with a chisel bar. I got most of it out with the bar but then I got the good idea to use a long 1 inch spade bit for wood boring. The drill bit made a much easier job of reaming it all out. You can see right into the cat once the muffler is unbolted. Wear eye protection when gutting the cat because the matrix is made from a very glassy stuff which goes everywhere and irritates the skin or eyes like fiberglass. Save the crushed matrix material for using as a catalyst for all your fun little chemistry projects which call for platinum (if you are into that kind of thing).

As an aside, you will see when you remove the honeycomb that it is incorrect to call it a "soot trap" because the holes are way to big to ever trap soot or get clogged up under normal conditions. Even if one were to never get the engine up to proper operating temp it would still never clog.

liberty2.8 · **Posted:** Thu Jan 29, 2009 12:39 pm

Quote:

Done it. The material which the honeycomb is made from is very hard, so it took a lot of banging with a chisel bar. I got most of it out with the bar but then I got the good idea to use a long 1 inch spade bit for wood boring. The drill bit made a much easier job of reaming it all out. You can see right into the cat once the muffler is unbolted. Wear eye protection when gutting the cat because the matrix is made from a very glassy stuff which goes everywhere and irritates the skin or eyes like fiberglass. Save the crushed matrix material for using as a catalyst for all your fun little chemistry projects which call for platinum (if you are into that kind of thing).

As an aside, you will see when you remove the honeycomb that it is incorrect to call it a "soot trap" because the holes are way to big to ever trap soot or get clogged up under normal conditions. Even if one were to never get the engine up to proper operating temp it would still never clog.

Did it get rid of that noxious exhaust smell and return to the normal smell of diesel exhaust? If so, I'm ready to start chiseling :wink:

Ooops, I think you already answered that question in a previous post, I'll be gutting this weekend.

BTW, was there any noticable difference in exhaust sound with a gutted kitty and still using factory muffler?

nursecosmo · **Posted:** Fri Jan 30, 2009 11:01 pm

Not really much change in sound that I can tell.

Exhaust Smell

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