Do you smoke in the mountains???

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Do you smoke in the mountains???

August 15, 2018, 09:40:20 pm

Just got back from Colorado and noticed that while driving at elevations I would briefly puff black smoke when taking off from a stop or hard exceleration. This is my 1st diesel so this might be normal, by the time I got home to sea level it was not doing it anymore. Is this normal, the Cummins ran great

Re: Do you smoke in the mountains???

Reply #1 – August 15, 2018, 10:22:07 pm

Black smoke is indicative of lack of air. At altitude there is less air.

Re: Do you smoke in the mountains???

Reply #2 – August 15, 2018, 10:26:07 pm

Yep, normal takes a few seconds for the turbo to get up to speed (spool up) to build boost.

Re: Do you smoke in the mountains???

Reply #3 – August 15, 2018, 11:13:48 pm

I was going to ask the same question. I'm ending an 11 week trip, and was concerned about a puff of black smoke when starting out while traveling through Utah. But not recently in Washington and Oregon coastal areas.

Re: Do you smoke in the mountains???

Reply #4 – August 15, 2018, 11:15:51 pm

Would this be a problem with getting smog checked?

Re: Do you smoke in the mountains???

Reply #5 – August 15, 2018, 11:17:30 pm

Quote from: Tom Lang – August 15, 2018, 11:15:51 pm

Would this be a problem with getting smog checked?

Not in California.

Re: Do you smoke in the mountains???

Reply #6 – August 16, 2018, 01:03:14 am

Quote from: hdff – August 15, 2018, 09:40:20 pm

Do you smoke in the mountains???

Not even the best cigars...

Re: Do you smoke in the mountains???

Reply #7 – August 16, 2018, 01:19:19 am

This was covered a few days ago in the post about overheating. Temperature and altitude go together to make less air available for the engine and do raise EGTs as well as causing a bit of smoke out the exhaust, especially starting from a stop when the turbo has not spooled up yet. So, high elevations along with high temperatures result in high "density altitude" where the engine can see an elevation several thousand feet higher than the road signs (or altimeter) says.

With the mechanical engines, you quickly learn by looking in the mirror just how much throttle to use without creating a cloud of black smoke behind you.

Items like a dirty air cleaner and or a cracked exhaust manifold/bad exhaust gaskets will compound the smoke off a stop sign or increase the amount of smoke showing in the mirror while going down the road.

Electronic diesels may have a "smoke" setting for the ECU that is accessible if you have a tool like the Pro-Link. This cuts the amount of fuel available to the engine at low boost pressures from normal performance settings. On the other hand, some ECUs can be programed to add a bit of fuel coming off a stop sign. This is more for the Foretravels with 4 speeds that have a 4.xx first gear ratio compared to a 6 speeds 6.xx ratio in first gear. It can't totally make up for the poor performance (especially at altitude) coming off the line but helps at the expense of more black smoke.

Since our diesel generators don't have turbos, they are really effected by hot weather and high altitude. So much so that they will create visible smoke and smell badly while running at elevation. Running the ACs at altitude will also generate higher EGTs while making the generator cooling system much less efficient and possibly exposing any cooling system fault.

Pierce

Re: Do you smoke in the mountains???

Reply #8 – August 19, 2018, 02:32:29 pm

Quote from: Pierce & Gaylie Stewart – August 16, 2018, 01:19:19 am

Electronic diesels may have a "smoke" setting for the ECU that is accessible if you have a tool like the Pro-Link. This cuts the amount of fuel available to the engine at low boost pressures from normal performance settings. On the other hand, some ECUs can be programed to add a bit of fuel coming off a stop sign. This is more for the Foretravels with 4 speeds that have a 4.xx first gear ratio compared to a 6 speeds 6.xx ratio in first gear. It can't totally make up for the poor performance (especially at altitude) coming off the line but helps at the expense of more black smoke.
Pierce

Pierce,
Thanks for the excellent description of ECU programmable smoke control!

I just checked with my Pro-Link to see if it was available on my engine but unfortunately it didn't show up on the list of parameters.
I don't know if Foretravel wanted to make available for our engines since most wouldn't have a Pro-Link to turn it on or off. Maybe Caflashbob can answer that question.

The user manual for DDEC I & II shows it in the available list of parameters. I wonder if it could be reprogrammed back in. Would be a nice feature to have!

Jerry

Re: Do you smoke in the mountains???

Reply #9 – August 19, 2018, 04:53:41 pm

Jerry,

Thank you! Our Detroits are programmed so they don't add much fuel until the boost pressure is up a bit. So, coming off a stop with the tall first gear ratio in the Allison 4 speed is a little slow, especially compared to excellent first gear ratio in the 6 speed the ~~devil~~ Cummins have. At 7000+ feet in Santa Fe starting from an uphill stop sign is slow. Some people modify the boost pressure sensor wiring to fool the ECU so it adds more fuel immediately so the acceleration is immediate. Unfortunately, it also adds smoke out the exhaust pipe.

After I retired from the department, I stopped in to one of the stations and the subject of smoke off the line came up. They had a Mack that everyone loved that drove it but really smoked coming off stops and low speed acceleration. The mechanical E7 engine was great for power but needed the pump recalibrated for low end smoke in city use.

Isn't the forum fun?

Pierce

Re: Do you smoke in the mountains???

Reply #10 – August 19, 2018, 05:55:54 pm

My mechanical DT 466 in the crane has an aneroid valve that doesn't let the engine get full fuel pressure until boost is up. When rebuilding the pump one time I forgot to hook up the boost line going to it and the engine was gutless. Took me a few minutes to figure out I hadn't screwed up the rebuild.

Re: Do you smoke in the mountains???

Reply #11 – August 19, 2018, 06:05:17 pm

Old Foretravel had the in-house ability to program their Detroit's.

Only one that was turned up that I got to drive was the original unicoach. But that's not fair as it had a series 60 Detroit in it.

Zero to 60 18 seconds. Fun fast. 10 mpg.

Did not know what a hill was.

Now as far as parameters go I had no idea.

But the first few 1998's were 277/840 torque. The later ones were 300820.

Side by side race the 277/840 was a full coach length plus in a side by side race.

CM mentioned to me that he had trouble understanding why any owner would want the less powerful version of the coach.

But he trusted me enough to change them to the 300 setting for marketing reasons.

Allison guy loved at the trans was rated for 780. They ok'ed the 840 because of the light load as the trans I think could be in a 40,000 pound vechile.

Re: Do you smoke in the mountains???

Reply #12 – August 19, 2018, 06:24:57 pm

On a diesel, more fuel equals more power until ie receives more fuel than it can use. A little puff of smoke tells me the engine is not getting shortchanged in the fuel department and is producing as much power as it can. No smoke tells me it is either exactly right of s little under fueled.

My 87 300D was originally designed to never smoke. It was gutless. My mechanic removed a gizmo that restricted fuel, and it became a beast. But I need to watch the rear view to limit smoke.

I was expecting a modern electronic diesel like my 2003 ISL to be smokeless, but it is surprisingly not so. Just one puff upon opening the throttle at altitude and higher temperatures. I'm ok with that, as long as I don't ever need to pass a no-smoke certification every year. Good thing I'm in California.

Re: Do you smoke in the mountains???

Reply #13 – August 19, 2018, 06:40:52 pm

And now, Scania V8s produce a max of 2580 ft-lbs of torque in their buses and trucks. Zero to 60 is probably limited by the glue holding the tire to the wheel. 16 liters but still very impressive. And all their engines are approved for HVO or Hydrotreated Vegetable Oil, a biodiesel without the short shelf life. Hard to believe Volkswagen controls this company.

Why are we not producing HVO or more of it? Read about HVO at: Is HVO the Holy Grail of the world biodiesel market? - Greenea

Pierce

Re: Do you smoke in the mountains???

Reply #14 – August 19, 2018, 08:42:17 pm

Five seconds of smoke was the standard for a 3208 cat. If not at altitude then the adjustment screw on the fuel pump needed adjusting.

Needs a "puff" of smoke on full throttle or its too slow in my opinion.

My gas car direct injections fuel into the cylinder after the intake valve is closed by computer.

So they are richening the mixture like a diesel.

Plus it's high compression. Feels like a diesel. Plus top end rev out. Crazy...

Re: Do you smoke in the mountains???

Reply #15 – August 19, 2018, 09:45:47 pm

With a Pro-Link the DDEC I & II user guide says you can reprogram the EEPROM and change the cruise control calculation, but you have to key in a password first. After you set the password you can select from a list of parameters you want to change. I haven't tried this but I assume this is where you may be able to turn the smoke control off if it is on that list. Any suggestions?

Jerry

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Do you smoke in the mountains???

August 15, 2018, 09:40:20 pm

Re: Do you smoke in the mountains???

Reply #1 – August 15, 2018, 10:22:07 pm

Re: Do you smoke in the mountains???

Reply #2 – August 15, 2018, 10:26:07 pm

Re: Do you smoke in the mountains???

Reply #3 – August 15, 2018, 11:13:48 pm

Re: Do you smoke in the mountains???

Reply #4 – August 15, 2018, 11:15:51 pm

Re: Do you smoke in the mountains???

Reply #5 – August 15, 2018, 11:17:30 pm

Re: Do you smoke in the mountains???

Reply #6 – August 16, 2018, 01:03:14 am

Re: Do you smoke in the mountains???

Reply #7 – August 16, 2018, 01:19:19 am

Re: Do you smoke in the mountains???

Reply #8 – August 19, 2018, 02:32:29 pm

Re: Do you smoke in the mountains???

Reply #9 – August 19, 2018, 04:53:41 pm

Re: Do you smoke in the mountains???

Reply #10 – August 19, 2018, 05:55:54 pm

Re: Do you smoke in the mountains???

Reply #11 – August 19, 2018, 06:05:17 pm

Re: Do you smoke in the mountains???

Reply #12 – August 19, 2018, 06:24:57 pm

Re: Do you smoke in the mountains???

Reply #13 – August 19, 2018, 06:40:52 pm

Re: Do you smoke in the mountains???

Reply #14 – August 19, 2018, 08:42:17 pm

Re: Do you smoke in the mountains???

Reply #15 – August 19, 2018, 09:45:47 pm

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