Exhaust Smell

Wobbly · **Posted:** Mon Oct 06, 2008 1:16 pm

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.

KJ Ash · **Posted:** Tue Oct 07, 2008 6:55 am

I find a bottle of aftershave in your tank usually helps! :lol:

Wobbly · **Posted:** Tue Oct 07, 2008 10:55 am

KJ Ash wrote:

I find a bottle of aftershave in your tank usually helps! :lol:

Should the bottle be opened before putting it in the tank?

Looks like SAE has done research on diesel exhaust odor:
http://www.sae.org/technical/papers/740216
http://www.sae.org/technical/papers/680444

This study seems to indicate that sniffing diesel exhaust may be an option to costly neurofeedback sessions:
http://www.idlefreevt.org/Diesel%20Fume ... tivity.pdf
"The findings "suggest an increased activity of the left frontal cortex during and after" diesel exposure, Dr. Borm and colleagues said..."

And this study may be of interest to hemp farmers:
"....The second set of experiments was based upon a situation present in an illicit
marijuana grow house in northern California. In the grow house, odors from immature
Cannabis sativa plants were combined with diesel exhaust from a generator and expelled out
through a chimney. Law enforcement officials reported being able to smell the marijuana
from a road several hundred yards away, and subsequently used this odor as probable cause
for a search. In this second set of studies, we first sought to determine whether the odor of
immature marijuana plants differs in quality or intensity from that of mature marijuana
plants. We then investigated whether participants were able to smell marijuana odor from a mixture emanating from immature C. sativa
plants when combined with diesel engine exhaust. The ratio of marijuana odor to exhaust
was modeled from the chimney effluence of the illicit California grow room...."

http://norml.org/pdf_files/brief_bank/m ... rstudy.pdf

UFO · **Posted:** Tue Oct 07, 2008 12:36 pm

Use biodiesel.

nursecosmo · **Posted:** Tue Oct 07, 2008 6:35 pm

When I gutted my cat I lost the eye stinging stink and now have a good smell when I crank it up.

jmoomaw · **Posted:** Tue Oct 07, 2008 6:55 pm

by CAT I assume you mean Catalytic Converter? I have thought about that with the HHO system, my emissions will be down to almost zero without it.

azroadposer · **Posted:** Wed Oct 08, 2008 10:45 pm

check for a diesel leak off the fuel rail

indication: oily spot on the underside of the engine cover.

warp2diesel · **Posted:** Sat Oct 11, 2008 10:28 pm

...my old Perkins did.

Did you do the lift pump mod yet?
Very small air bubbles caused by the negative pressure and micro leaks retard the injection timing poor running, and make the exhaust stink more.
Another thing that will cause more odor is contamination from Zinc used on galvanized pipe.
Zinc acts like a catalyst forming more aldehydes which cause increased pungent odors.
Zinc is great as a trace element in food supplements, in fact the only way you can hurt yourself with zinc is to make it into a weapon and use it on your self, but don't contaminate your fuel with it.

I did use galvanized pipe for my fuel tank filler pipes on the old Perkins, guess I should have followed my own advice.

nursecosmo · **Posted:** Sat Oct 11, 2008 11:45 pm

warp2diesel wrote:

...my old Perkins did.

Did you do the lift pump mod yet?
Very small air bubbles caused by the negative pressure and micro leaks retard the injection timing poor running, and make the exhaust stink more.
Another thing that will cause more odor is contamination from Zinc used on galvanized pipe.
Zinc acts like a catalyst forming more aldehydes which cause increased pungent odors.
Zinc is great as a trace element in food supplements, in fact the only way you can hurt yourself with zinc is to make it into a weapon and use it on your self, but don't contaminate your fuel with it.

I did use galvanized pipe for my fuel tank filler pipes on the old Perkins, guess I should have followed my own advice.

Nearly all vacuum to IP injection systems have small bubbles in the fuel stream but they have no affect at all on performance. This is because as they are compressed to 1600 bars they are instantly squeezed into non existence as they return to saturation. The particular problem with our system is that over time the little bubbles tend to collect at the highest point in the fuel system which is the fuel filter head, where they buildup until a large bubble is sucked into the IP. When this happens there is a sudden and dramatic loss of pressure in the fuel rail down to just a few hundred PSI or less.
The timing is not affected at all because our timing is controlled by the ECU. The process that gives the appearance of retarded timing (lots of stinky white smoke) is the fuel not being atomized because of the low injection pressure thus causing it to exit the engine almost completely unburnt. The same process is happening when you have a plugged fuel filter as well. This is just an FYI regarding common rail systems which manifest problems differently from hydraulic, PD and HEUI fuel injection systems.

warp2diesel · **Posted:** Sun Oct 12, 2008 12:14 am

nursecosmo wrote:

Nearly all vacuum to IP injection systems have small bubbles in the fuel stream but they have no affect at all on performance. This is because as they are compressed to 1600 bars they are instantly squeezed into non existence as they return to saturation. The particular problem with our system is that over time the little bubbles tend to collect at the highest point in the fuel system which is the fuel filter head, where they buildup until a large bubble is sucked into the IP. When this happens there is a sudden and dramatic loss of pressure in the fuel rail down to just a few hundred PSI or less.
The timing is not affected at all because our timing is controlled by the ECU. The process that gives the appearance of retarded timing (lots of stinky white smoke) is the fuel not being atomized because of the low injection pressure thus causing it to exit the engine almost completely unburnt. The same process is happening when you have a plugged fuel filter as well. This is just an FYI regarding common rail systems which manifest problems differently from hydraulic, PD and HEUI fuel injection systems.

I disagree:
1) Any measurable quantity of air in the system causes a delay in injection timing since the system is not a closed loop system with an optical sensor in each cylinder.
2) Since the Common Rail is not a closed loop system, the ECU makes a Educated Guess as to when to fire the injector based upon the map that has been programmed into the memory with some allowance for learning, but has no way to confirm it. Imotion sells a more aggressive map than the stock Chrysler map.
3) Any measurable quantity of air results in loss of fuel volume, an increase in the fuel temperature, and by reducing the quantity, delaying the timing.
4) Large enough air bubbles are the only ones caught in the high points, having a chamber large enough to get rid of air sucked in is impractical due to the lack of real estate in the engine compartment.
5) A lift pump eliminates the air bubble headaches and is the cheapest fix available.
6) Not having a lift pump is a Dumb @$$ Bean Counter stunt Chrysler pulled on us.
7) A very old Engineering principle that states that it is easier to control 1000PSI than to control a Vacuum. Since my lift pump and most others operate at 9 PSI, it is 111 times easier to control any fuel leaks than vacuum leaks in the STUPID STOCK FUEL SYSTEM that sucks fuel out of the tank through the filter and past snap fittings designed to operate under pressure. Hence, VACUUM AIR LEAKS :!:

nursecosmo · **Posted:** Sun Oct 12, 2008 12:28 pm

warp2diesel wrote:

I disagree:
2) Since the Common Rail is not a closed loop system, the ECU makes a Educated Guess as to when to fire the injector based upon the map that has been programmed into the memory with some allowance for learning, but has no way to confirm it.

Exactly! The ECU is the one and ONLY thing that controls Injection timing. When I stated earlier that the timing is not affected by large amounts of air I meant that it is not retarded by it. The ECU factors in rail pressure, RPM and accelerator position and opens for a prescribed amount of time at the appropriate degree of advancement. It only has a limited range for variation programed into the fuel mapping. What happens when the rail pressure drops from sucking up a large chug of air is that the timing is advanced to the maximum level. this is the same level where it injects at startup when the rail pressure is low. By low startup pressure we are talking ~4000 psi. When the rail pressure is only in the few hundred pound range the the fuel is squirted out in a stream instead of a spray. This inhibits proper combustion and causes the white smoke.

warp2diesel wrote:

3) Any measurable quantity of air results in loss of fuel volume, an increase in the fuel temperature, and by reducing the quantity, delaying the timing.

Absolutely not. If you get a 1mm air bubble into the IP it gets compressed down 1600 times. A human cannot even see a dot 1/1600th of a millimeter across and it in fact does not even exist because it goes instantly into solution at the molecular level. As far as a loss of rail volume it must be remembered that the fuel rail is designed to be elastic like a balloon in order to mitigate the changes in rail pressure and volume each time that an injector opens. The ultimate control of pressure and volume is the cascade valve on the end of the rail. Only a very large bubble can instantly stop the IP from pumping fuel into the rail.

warp2diesel wrote:

5) A lift pump eliminates the air bubble headaches and is the cheapest fix available.
6) Not having a lift pump is a Dumb @$$ Bean Counter stunt Chrysler pulled on us.
7) A very old Engineering principle that states that it is easier to control 1000PSI than to control a Vacuum. Since my lift pump and most others operate at 9 PSI, it is 111 times easier to control any fuel leaks than vacuum leaks in the STUPID STOCK FUEL SYSTEM that sucks fuel out of the tank through the filter and past snap fittings designed to operate under pressure. Hence, VACUUM AIR LEAKS Exclamation

Amen!!! A lift pump is the only way to go to avoid all of the associated problems with fuel in air.

mackruss · **Posted:** Sun Oct 12, 2008 1:57 pm

nursecosmo wrote:

warp2diesel wrote:

I disagree:
2) Since the Common Rail is not a closed loop system, the ECU makes a Educated Guess as to when to fire the injector based upon the map that has been programmed into the memory with some allowance for learning, but has no way to confirm it.

Exactly! The ECU is the one and ONLY thing that controls Injection timing. When I stated earlier that the timing is not affected by large amounts of air I meant that it is not retarded by it. The ECU factors in rail pressure, RPM and accelerator position and opens for a prescribed amount of time at the appropriate degree of advancement. It only has a limited range for variation programed into the fuel mapping. What happens when the rail pressure drops from sucking up a large chug of air is that the timing is advanced to the maximum level. this is the same level where it injects at startup when the rail pressure is low. By low startup pressure we are talking ~4000 psi. When the rail pressure is only in the few hundred pound range the the fuel is squirted out in a stream instead of a spray. This inhibits proper combustion and causes the white smoke.

warp2diesel wrote:

3) Any measurable quantity of air results in loss of fuel volume, an increase in the fuel temperature, and by reducing the quantity, delaying the timing.

Absolutely not. If you get a 1mm air bubble into the IP it gets compressed down 1600 times. A human cannot even see a dot 1/1600th of a millimeter across and it in fact does not even exist because it goes instantly into solution at the molecular level. As far as a loss of rail volume it must be remembered that the fuel rail is designed to be elastic like a balloon in order to mitigate the changes in rail pressure and volume each time that an injector opens. The ultimate control of pressure and volume is the cascade valve on the end of the rail. Only a very large bubble can instantly stop the IP from pumping fuel into the rail.

warp2diesel wrote:

5) A lift pump eliminates the air bubble headaches and is the cheapest fix available.
6) Not having a lift pump is a Dumb @$$ Bean Counter stunt Chrysler pulled on us.
7) A very old Engineering principle that states that it is easier to control 1000PSI than to control a Vacuum. Since my lift pump and most others operate at 9 PSI, it is 111 times easier to control any fuel leaks than vacuum leaks in the STUPID STOCK FUEL SYSTEM that sucks fuel out of the tank through the filter and past snap fittings designed to operate under pressure. Hence, VACUUM AIR LEAKS Exclamation

Amen!!! A lift pump is the only way to go to avoid all of the associated problems with fuel in air.

Can i just interrupt you guys for a minute, I have yet to install the lift pump due to procastination as to in tank or in line pump, the latter i understand to be the cheaper option. I don't seem to have an air problem or stutter at 55mph so is this air problem specific to certain models only :?:

warp2diesel · **Posted:** Sun Oct 12, 2008 8:14 pm

ALL KJ CRDs

onthehunt · **Posted:** Sun Oct 12, 2008 8:32 pm

I must have a special edition. Stock fuel system and no problems. If a lift pump fixes something for you it is only covering up a larger problem.

warp2diesel · **Posted:** Sun Oct 12, 2008 8:36 pm

onthehunt wrote:

I must have a special edition. Stock fuel system and no problems. If a lift pump fixes something for you it is only covering up a larger problem.

He may bump one of your snap couplings and start an air leak :lol:

nursecosmo · **Posted:** Sun Oct 12, 2008 11:00 pm

Perhaps they all have the potential to leak. If your fuel is well aerated while cool, when the fuel heats up from a lot of stop and go in hot weather, it will almost certainly start sucking large air bubbles especially after sitting for a while and letting the heat soak in and you will have a P0093. Another problem which I suspect determines why some owners have the problem and others don't, is the condition of the fuel filter. If it is new and has very little restriction there is less of a vacuum to pull bubbles out of solution.

onthehunt · **Posted:** Sun Oct 12, 2008 11:30 pm

Quote:

He may bump one of your snap couplings and start an air leak

No chance, I have skids installed for that very reason!! :lol:

mackruss · **Posted:** Mon Oct 13, 2008 12:40 pm

nursecosmo wrote:

Perhaps they all have the potential to leak. If your fuel is well aerated while cool, when the fuel heats up from a lot of stop and go in hot weather, it will almost certainly start sucking large air bubbles especially after sitting for a while and letting the heat soak in and you will have a P0093. Another problem which I suspect determines why some owners have the problem and others don't, is the condition of the fuel filter. If it is new and has very little restriction there is less of a vacuum to pull bubbles out of solution.

Sorry up front if these are stupid questions;

I have done 76000km's now and have only primed the filter head once and released a miniscule amount of air, my question is - must the vehicle be running or shut down when priming or is it immaterial?

Second question - i've read about the CRD running quieter after fitting a lift pump - why would she run quieter?

nursecosmo · **Posted:** Mon Oct 13, 2008 6:39 pm

Most likely the noise reduction is only in the minds of those who have installed them, but there might be a slight reduction in noise if the IP is not working as hard to pull fuel up all the way from the tank. When I installed my first pump it was a Holly Blue. When I would turn the key on it sounded like a jet engine. I removed it the first chance I got and installed an Airtex Duramax pump. Now you can barely hear the shuttle working and it catches on the first crank of the engine. Any possible gains in noise reduction will quickly be offset if one were to do the Catgut mod to improve exhaust smell though.

ATXKJ · **Posted:** Mon Oct 13, 2008 7:23 pm

mackruss
priming has to be done while the engine is stopped - if it's running the entire system is under vacuum and opening the bleeder will pull air in.
also I'm assuming the 'quieter with lift pump' comes from air bubbles injected into the engine as causing it to run rough - and no bubbles means it's injecting a consistent amount - therefore smoother.

(if you're running well and install a lift pump - there shouldn't be a difference - it's a safety precaution)

Exhaust Smell

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