engine runs rough on start up

[ncduece]

my ldt 465 is hard to start and runs very rough on cold start up, it clears up after a minute or so engine runs great afterwards . changed fuel filers no difference. what should i look into first?

 

[poppop]

Does it do the same in warm weather or just when its cold outside??

 

[ncduece]

warm or cold

 

[ncduece]

i am running mostly old gas. suppose i can try fresh diesel

 

[Divemaster920]

Look for ANY fuel leaks. If fuel leaks out when under use, then air gets into the system when not running.

 

[Keith_J]

Injector balance. You have to find a shop with the necessary equipment to do this. The injectors are closed until injection pressure is sufficient to unseat the needle's spring pressure. As the injectors wear or are gummed up, different pressures are needed to unseat the needles and therefore, some cylinders don't fire.

The governor is trying to keep idle speed constant but it is impossible for the governor to compensate these cylinders, instead, the next injector gets a bigger swig of diesel, making that cylinder run stronger. The governor then cuts back fueling, causing another lope.

You could take the injectors out and give them a cleaning. Pro Shot Copper Solvent IV, available at good gun shops, readily dissolves injector goo. It works better than any other solvent.

 

[Barrman]

What is your idle rpm with the truck warm? It should be 800-1000. If you are a bit lower than that, then turn it up and see if your starting issues go away.

Personally, I think you have more of a fuel related issue than anything else. The more pure diesel in my tank, the better mine starts in any weather. Last winter with mostly oil in the tank anything below 50 degrees caused me a lot of starting issues in the mornings. This year it fires right off below 20 degrees. (yes, I went out and tried it last weekend when we were having record cold temps.) However, it will run rough until it warms up. Not shaking the truck off the tires rough, but rougher than when it is warm out.

 

[Heavysteven]

Had the same problem (only had the truck a month). Changed the oil, put in a diesel conditioner, and drained the fuel filters. Still runs rough in the cold 15-20. Put once it's warm runs smooth. I swear it likes new oil and new diesel. I would try that first and the move up the list.

Good luck

 

[sandcobra164]

Mine's a little rough in 15 to 20 degree weather. Anything above freezing and she's good. In the 15 to 20 degree weather, I just give enough throttle to keep it right above 1,000 rpm's and she's good after about 20 seconds. I've got the flame intake heater and have not used it for worry of cracked lines or bad O rings and I've never used ether on the truck. She was a little slow to start last night (10 seconds of starter time and the temp was 15 according to the weather channel.)

 

[Heavysteven]

Well, I used my flame heater yesterday switch above the wipers. I followed the directions only activated during cranking, lots of smoke. Did not know about the risk of cracked lines or o rings. That being said it helped start the truck.

 

[derby]

I think the old gas is the problem, try increasing your diesel in the tank. the diesel will help lube the pump better also.