This problem started just about a month ago. The colder it gets the more cranking it takes to start. It used to start, when cold, with about five seconds of cranking and now it is more like ten to fifteen seconds of cranking. When it starts it runs rough with not all cylinders firing and generates a lot of smoke. It runs normally after about half a minute to a minute. The engine smokes a bit when hot or cold and it has never done this before.

No codes. Grid heater works well. Lift pump pressure is a steady 11 psi and it has been at 11 psi for the last six years. No leaks in fuel plumbing. I pressurised the fuel tank to 10 psi with compressed air and checked for leaks everywhere, including the supply side and the drain side including the tee fitting at the back of the cyl head.

Truck has 342000 kms/214000mi, more importantly engine hours is at 13500 hours. Original injectors and they never have been touched. VP44 is about eight years old. I have access to Cummins Insite, which is the software that works on Freightliner trucks with a six pin Deutsch connector. I tried disabling injectors one at a time and the hot smoke never went away.

Read the Blue Chip Diesel article on the VP44 and the hot smoke symptom does not match any of the scenarios listed in the article.

Any suggestions are most welcome.

 

Generally the reasons for what you're experiencing are either:

1) Battery condition. Both batteries must be the same age, size, and condition. One having bad cells will cause the whole system to suffer.

2) Slow cranking start. A mere 20 rpm reduction will cause starting issues. Either the starter has been replaced with a cheapo over the counter lifetime replacement unit which is only as good as the few bucks it cost, or the OEM starter is dragging. Usually the OEM Denso starters dont drag either unless there's voltage/amperage problems from poor battery conditions or corrosion issues on the batteries, cables, or any major ground. The ISB Cummins is fully electronically controlled and is very sensitive to voltage/amperage conditions.

3) The grid heaters arent work or not working correctly. Even though the volt gauge dips does not mean the grids are heating up. Feel the manifold for heat to assure that they're working. Diesels require addition help to heat the intake air during cold start-up's since the only heat generated during engine cranking is from the compression process. Usually a good way to diagnosis if the grids are the problem is to plug the block heater in during the night and see if that helps starting during the cold morning. If it does then your engine obviously isnt getting optimal intake temps without the assistance of the block heater. This may help. Ram Diesel Manifold Heater Problems

That said, if voltage/amperage issues are the true cause then plugging the block heater will help too since it takes a tremendous amount of juice to crank over these chucks of iron. And the grid heaters pull copious amounts of energy from the batteries too. If you drive your truck for many short distance around the town trips during cold weather, without any long continuous drives, the grid system will actually deplete the batteries as the charging system doesnt have the power to replenish during short drives and overcome the amount of energy used by the grids repeated cycles.

 

I will check cranking speed and grid heater amperage but neither accounts for smoke when engine is hot. Also slow cranking speed would not account for some cylinders not firing after start up. Will report back.

 

I made the assumption that this hard starting was only happening when the engine was cold. If it hard starts when the engine is hot then what I listed is not your problem.

But after reading your post again, I'm not sure what you mean by "smokes a lot" because the exhaust will always throw out a decent little puff of smoke when you first start the engine, hot or cold. But if the smoke is excessive, hot or cold, then it could still be a result of the grid heaters not working properly. Again, diesels need intake heat help to aid in optimal starting unless the ambient temps are fairly warm outside. And yes, this could still be the reason why not all cylinders are firing until the engine runs for a second.

 

Just throwing this out, but is the engine coming up to full operating temp?

 

Yes, the temperature gauge shows normal reading. The engine starts easily when warm or hot.

I have had the truck for fifteen years, so when I say the truck is smoking excessively when first started, believe me, the smoke is excessive The excessive smoke only lasts for a few minutes but then the light smoke starts and persists even when the engine is hot. The grid heaters do not play any role once the engine is hot, no matter how low the ambient temperature, so the 'smoke when hot' makes me suspect injectors or VP44.

I won't get to checking the grid heater for a few days but, when I do, I will post the results.

I don't have the block heater any more, it has been replaced by a frost plug.

 

The grid heaters do continue to play a part in ALL start ups unless the ambient temperature outside is warm enough for the ECM to not engage the grid system at all. Even if you're driving around and the engine is up to full temperature, upon re-starting the engine the grids will cycle again for up to three minutes in order to assure that the intake remains warm. Again.....even if the engine is up to full operating temperature. The only way to stop the grids from cycling is to drive away at more than 17-20 mph.

But that said, if the engine is smoking excessively during your normal run around driving and hazes when idling then it sounds like an injector is not working right. Maybe some debris stuck in the pintle valve. If you have a way to post a video of what the trucks doing (smoke wise) then that may help.

 

I'm not sure what years may have had what changes, but my heaters will cycle up to at least 40 mph.

 

That is most certainly NOT normal for any second gen Dodge Cummins truck.

Your sig shows all kinds of changes and modifications to the trucks electrical and monitoring systems which would point to a possible reason why your grids cycle like that.

 

the grid cycle changed when I used the 01 ecm on the engine swap.

 

Weird. Maybe the ECM is working under incorrect parameters and needs to be re-flashed.

 

Flash is fine. Checked twice on drb. Once when engine was installed and again a few months later when we put stock tire size back in. No errors. All parameters normal. Too many fallacies roaming the web to believe all that's written on these drivelines. just like the one that says the alternator is kicked out when the grid heaters turn on.
maybe the program was updated for later emissions on the 01. Either way, no problem.

 

Re grid heater and hot starts, I will keep an eye on the voltmeter on my next hot start to see the grid heater coming on.

I checked the Cummins Engine Operator Manual that came with the truck and also the Cummins Factory Service Manuals for the ISB and none of them specify the criteria under which the ECM turns on the grid heater.

I checked a Caterpillar C7 Engine Operator Manual and it specifies that the ECM turns on the grid heater when the sum of coolant temperature and intake air temperature is less than 25C/77F. So, at least on the Cat, the grid heaters do not come on on hot starts since the coolant temperature will ensure that the sum is always greater than 25C, unless ambient drops to -(90 coolant temp - 25) = -65C!

I will take a video of the hot smoke and see if it shows on the video. It won't be for a few days, though.

 

I dont know what to tell ya guys. You're more than welcome to do and think whatever you choose, and thats the joy of these forums. No one should be twisting arms.....

All I know is I've been sharing info around these Cummins/diesel forums for too long and I think I'm plenty up to speed on the 2nd gen trucks. Thats not to claim I know everything as I'm always learning.....and open to learning too. But that said, there is nothing I've ever read or heard of which would give me reason to doubt what I've already talked about on the grid heater system.....for the Dodge Cummins. Sure, there's plenty of who toss out opinions like they're fact but thats something I certainly try not to do. I'm only here to help in any way possible.

So.....in regards to smoking, does the truck do anything like this?

 

Well, smoke even when warm would make me leant towards VP44 or injectors.
Since you checked the IP and have no codes I would take a good look at the injectors.
Improper atomisation increases the needed temperature to get the diesel to ignite sufficiently to keep the engine running.
So during the rather slow cranking there is a lot of time for the compression heat to "flee" through the cold cylinder wall, the piston and the head.
At idle rpm it is a bit "better" since there is less time. When the engine is warmed up even very bad spray patterns will keep the engine running, up to a point where you have soot at idle.
One reason you should also check this is that with a bad spray pattern and improper atomisation the burn can get a lot closer to the piston crown than intended by the manufacturer, and this can lead to the piston gettin too hot to fit in the bore...

HTH