Cummins smoking at low rpm's under load.

[Kamper Dave]

Our 2004. 5 Dodge Ram 2500 with Cummins Turbo Diesel was a great truck. We purchase it in 2009 with 51,000 miles on the odometer we are now up to 101,000 miles. She only works once a year when we tow our 5th wheel to Montana and back. We use her for daily transportation 7 months while working for the summer, during the winter she is in storage but started each month and run for at least an hour. We faithfully use Stanadyne and the battery minder is hooked up all winter. We removed the Bully Dog Torque 600 that it came with.

This spring the original batteries refused to hold a charge and were replaced. The ECM died during battery replacement and it was replaced and reprogrammed by the nearest dealership. We towed the RV to Montana and thought we noticed a lack of power. After unhitching the RV we noticed that we were exhausting white smoke while climbing the slightest hill. Thinking that we purchased bad fuel we dumped fuel via the separator and had the filter replaced; we also cleaned the air filter. This helped a little. We then drove to an authorized Cummins dealer to have the engine checked out. They said that they checked the intake and all was normal except for the injectors. The handheld device showed that four injectors were high 103% to 107% and one was low in the 90% area. All 6 were replaced with Bosch Cummins Injectors. This helped quite a bit and there is restored power but we still smoke under load especially with low RPM’s (under 1400 RPM’s). We have run through several tanks of fuel and still she smokes. This morning even on an easy acceleration we were exhausting black smoke, punching down of the fuel turns it to a grey haze. Once the rpm’s are up very little smoke is seen.

If run in Tow and Haul then no smoke is visible but that is at higher rpm’s.

Any suggestions would be helpful. What is the next step?

Trade her in?

Kamper Covey

 

[cerberusiam]

First question, were those absolutely positively NEW injectors?



Its possible you need to disconnect the battery cables, tie the gound cables together, and drain all the potential capacitors in the electronics. Its cheap and easy and every once in a while it resets things.



However, the reality is you probably got reman injectors, even Bosch remans are crap. The grey haze and more smoke than normal has always ended up being an injector issue in my experience.



Have any idea what your fuel mileage is at this point?



I would take it back to the place that did the work, show them the smoke and tell them very emphaticaly that wasn't there before. Wonder what a cylinder contibution test would show at this point?

 

[VZotz]

You may want to look into the service bulletin that talks about reflashing the ECM because of this specific concern. Although there could be multiple reasons as to the cause. My 05 has been doing this since day one but I am not going to have the bulletin completed.

 

[ata]

If you are running that motor at 1400 RPM's or less you are LUGGING it to DEATH. You have vary little to no boost at that RPM. No air add fuel = SMOKE. Get it up into it's operating range and it won't smoke. Good Luck

 

[LNaugle]

i agree with cerb... . just cause they are a cummins dealer doesnt meen they know what they are doing... if you have problems with them then call cummins in salt lake with your pn#s and find out what they really put in there... . i had a customer that bought injectors for his 03 and they first sold him the wrong year injectors,then he returned them and they sold him 250 horse injectors for 305 hp truck... . they argued he called diff cummins and they gave him the proper pn and told him they had the proper ones in stock at the place where he originally bought em... .

 

[rscurtis]

If you are running that motor at 1400 RPM's or less you are LUGGING it to DEATH. You have vary little to no boost at that RPM. No air add fuel = SMOKE. Get it up into it's operating range and it won't smoke. Good Luck

I disagree. IIRC, some of the CR engines produced maximum torque near 1500 RPM, so that implies full throttle at that speed. Diesel engines have been virtually smokeless since Jan 1. 1994. A stock CR engine shouldn't smoke no matter what you do with it.

 

[Prairie Dog]

I dissagree too. Unless it's tuned to the extreme the Cummins runs great at those lower eng speeds. Even with the Smarty I don't get smoke unless I put my foot into it hard. Stock it only puts out a slight puff at times. Being stock, if it smokes more than a small puff or keeps smoking then something is wrong.
If your climbing a hill under heavy throttle with a load then you will get a greyish haze. Heavy black smoke is not normal.

 

[LNaugle]

you guys still have stock exhaust with cat. ?

 

[mini14]

i have a gray haze visible only at night, and will blind the person behind me with black smoke if i floor it... .completly stock and runs great

 

[HBellmyer]

smoke

Black smoke= not enough air or boost. White smoke= over fueling. Blue smoke= burning oil.....

 

[leaky gasket]

According to the turbodiesel buyers guide. Max torque for the OP truck is at 1600 RPM anything below that and you are lugging it.

 

[Prairie Dog]

Just because you operate an engine at below max torque doesn't mean your lugging it.
Cummins literature says as long as you can give an eng more throttle and get acceleration, they do not consider the eng lugging regardless of RPM. But, you can under those guidelines, lug an eng at red-line!

 

[AEdelheit]

I would not put a heavy load on a Cummins at 1400 RPM, just because it can doesnt mean its good for it. Anyone who thinks its fine should drive a twin disk, solid flywheel truck where all the vibrations are transmitted and not covered up, you will change your mind quickly.

 

[pjorlando]

The insides of my exhaust tips are black, my truck smokes when I'm into the throttle, otherwise hardly noticable.

 

[AH64ID]

Just because you operate an engine at below max torque doesn't mean your lugging it.
Cummins literature says as long as you can give an eng more throttle and get acceleration, they do not consider the eng lugging regardless of RPM. But, you can under those guidelines, lug an eng at red-line!

They also say not to run at 100% throttle for more than 60 seconds below peak torque.

 

[Prairie Dog]

Come to think of it, after reading this and other forums for 10+ years, I have never read of any kind of eng damage from lugging. transmission's yes, but never engines.

 

[cerberusiam]

Come to think of it, after reading this and other forums for 10+ years, I have never read of any kind of eng damage from lugging. transmission's yes, but never engines.

Need to spend more time digging in the 12V forums . The next time you read about somebody having to much end play in the crank and finding the thrust bearings wiped you will have your answer. These engines no likey lugging, eats bottom ends.



These CR's and 24V's are fuel managed so its almost impossible to lug them in that range, they just won't run. Anything under 1600 rpms is considered idle time by Cummins, and for the most part your not pulling a load under 1800 rpms with any regularity.

 

[Bob4x4]

Need to spend more time digging in the 12V forums . The next time you read about somebody having to much end play in the crank and finding the thrust bearings wiped you will have your answer. These engines no likey lugging, eats bottom ends.

These CR's and 24V's are fuel managed so its almost impossible to lug them in that range, they just won't run. Anything under 1600 rpms is considered idle time by Cummins, and for the most part your not pulling a load under 1800 rpms with any regularity.

Very true the ultra low rpm some people want to use will do some damage to bottom ends as well as breaking drive train parts from bad frequency harmonics. Lug my 1000 lbft 12 valve in 5th and feel it through out the whole truck

 

[Prairie Dog]

LOL, I don't think I could possibly spend more time on these sites!!
Nope, I don't consider it a problem especially on an engine that's anywhere near stock. Bearing problems on a Cummins? Even engines that are close to the million mile mark don't have issues.

Now if you want to make an argument out of it and try to change minds then go ahead but you'll never convince me given the experience and data I've read over all these years. BTW, this aint my first Cummins either.

 

[NIsaacs]

How does low rpm equate to thrust bearing stress? I know the angle cut front gear train keeps some pressure on the thrust bearings as does holding the clutch in, but just low rpm? Inquiring minds want to know



Nick