Engine stumble or fuel starve ?

[Edward972]

Today while on grades headed towards Yellowstone and pulling a toad, the engine lost power or stumbled on several occasions. Each time they were brief, and the engine powered back, but happened on a tough grade that I barely cleared. Once back on flats it purred and turbo responded as normal. It’s a 2008 340 , 36qs. Anyone have this happen and if so, what was your fix. Thanks in advance.

[kfergiez]

Originally Posted by Edward972

Today while on grades headed towards Yellowstone and pulling a toad, the engine lost power or stumbled on several occasions. Each time they were brief, and the engine powered back, but happened on a tough grade that I barely cleared. Once back on flats it purred and turbo responded as normal. It’s a 2008 340 , 36qs. Anyone have this happen and if so, what was your fix. Thanks in advance.

Unless there is a very common issue, it's highly unlikely that somebody will have a quick fix since there are so many issues that could caused your problem.

Have you look at your air and fuel filters? Have you drained your fuel/water separator? Have you checked for an exhaust or cat blockage?

I would start with the cheapest and simplest maintenance items.

[NMWildcat]

Originally Posted by kfergiez

Unless there is a very common issue, it's highly unlikely that somebody will have a quick fix since there are so many issues that could caused your problem.

Have you look at your air and fuel filters? Have you drained your fuel/water separator? Have you checked for an exhaust or cat blockage?

I would start with the cheapest and simplest maintenance items.

X2. Exactly this. Check filters first. Have tech look for service bulletins pertaining to this problem. Look into a FASS lift pump if there are no obvious problems/fixes.

[DieselDrax]

X3, definitely sounds like a fuel or air filter that needs to be replaced. High engine load up hill is going to need the most fuel and is going to expose any fuel starvation issues. If it's a fuel supply issue this can also be checked with a scan tool watching fuel rail pressure under WOT to see if it's dropping below the demand pressure. I would expect to see a code or warning light for this but perhaps that year/model doesn't provide that.

I would expect the air filter to either have a "filter minder" gauge on the filter housing that shows the max restriction it has seen or a sensor to detect and trigger a warning light/message on the dash indicating the air filter needs to be replaced.

When was the last time the air and fuel filters were replaced? How many miles/engine hours?

[Oscarvan]

Originally Posted by DieselDrax

If it's a fuel supply issue this can also be checked with a scan tool watching fuel rail pressure under WOT to see if it's dropping below the demand pressure. I would expect to see a code or warning light for this but perhaps that year/model doesn't provide that.

I would expect the air filter to either have a "filter minder" gauge on the filter housing that shows the max restriction it has seen or a sensor to detect and trigger a warning light/message on the dash indicating the air filter needs to be replaced.

When was the last time the air and fuel filters were replaced? How many miles/engine hours?

All this.

Is the maintenance up to date? If the answer is yes, it's time to connect a data reader and see what various parameters are doing.

[Edward972]

Thanks to everyone that responded with suggestions. All maintenance is up to date. I do understand that there is not likely a simple fix. Best I can do for now is wait till I leave the RV Park in 4 days and get to a populated city. Will be in Rapid City, SD in a week. I’ll locate a Cummings repair location and have them check all that you have mentioned.

[Iwannacamp]

I suggest to find a Seafoam seller and put the appropriate amount to match fuel quantities. Normally it’s 16oz to 20 gals. Walmart and Napa sell it normally.

May not fix problem...but it easily can and it will help the fuel system.....and it won’t hurt it.

[DieselDrax]

Originally Posted by Iwannacamp

I suggest to find a Seafoam seller and put the appropriate amount to match fuel quantities. Normally it’s 16oz to 20 gals. Walmart and Napa sell it normally.

May not fix problem...but it easily can and it will help the fuel system.....and it won’t hurt it.

I wouldn’t use Seafoam in a diesel, personally. The best product that’s available just about everywhere is Power Service Diesel Kleen. A double dose will help clean things up quite well and quiet down the engine as well.

[Oscarvan]

Originally Posted by Edward972

I do understand that there is not likely a simple fix.

It may very well BE a simple fix. What is hard is finding what is out of order. There are a LOT of simple fixes.

[Jim34RL]

Originally Posted by Edward972

Thanks to everyone that responded with suggestions. All maintenance is up to date. I do understand that there is not likely a simple fix. Best I can do for now is wait till I leave the RV Park in 4 days and get to a populated city. Will be in Rapid City, SD in a week. I’ll locate a Cummings repair location and have them check all that you have mentioned.

When was the last time you fueled up and what station!

Even though you have changed your fuel filter/filters, if more than one per the maintenance schedule, they still could be slightly plugged. A bad load of fuel can easily cause you performance issues when you are under power. Have you checked for a little water in your water filter separator and have you drained this?

Just another easy suggestion for you to review for a fix.

I also always carry two spare fuel filters for my two fuel filters on my truck, in case of bad fuel when I am on the road.

[Vince and Charlette]

I have to agree, it's likely a water separator issue, which is easy to check, or a fuel filter. Also, when taking hills, check that the transmission "Mode" select button is off. It is good to use it most of the time except for when accelerating at freeway onramps or when in mountains. Essentially, it changes the shift point to improve fuel economy, but you lose a little torque as a tradeoff. Regarding fuel additives, Freightliner recommends "Power Service Diesel Kleen + Octane Boost." Regardless, always look for the "Endorsed by Cummins Inc." on the label...usually on the front. (32oz. per 100 gallons; add to every fourth fillup.) PS - be sure you're not using cruise control on moderate to steep hills.

[1acer]

My 2008 Berkshire does the same thing. I have changed both air and fuel filters and the issue remains. Someone mentioned that it could possibly be a turbo issue.

[debit]

My Cummins had similar problems last week in Canada and I eventually had to be towed. After a motor diagnostic test, the Dodge dealer found that the problem was the fuel transfer pump.


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Ram 2500 diesel / FR Surveyor 251rks