engine help

[bbf]

the 5 ton i just pickup when first start up the cummmins the engine rev up and down and when it warms up and you hit the pedel it dose it again for a few seconds . why

 

[Westech]

well mine does rev up and down when I first start it. its like the engine is 10 seconds behind the gas pedal. but its fine after it warms up. Now remember its not going to have the throttle response as a gas engine warm or cold.

 

[Pappa-G]

Mine was also very slow on throttle response. So I drained the old fuel and changed the filter. HUGE DIFFERENCE! Also run some fuel conditioner through it and go for a 50 mile drive so every thing warms up nicely. Circulating the clean fuel through things made a world of difference for me. The old stuff was better than 3yrs old.
Good luck!

 

[timntrucks]

thats sounds like old worn fuel. if it keeps it up after you get it cleaned might have a little air sucking problem

 

[WillWagner]

thats sounds like old worn fuel. if it keeps it up after you get it cleaned might have a little air sucking problem

Or high or low throttle shaft leakage, or a lose overhead, or not getting full throttle. Put some good fuel in it and run it a bit and see what happens. Run it down the road, not idle time.

 

[jwaller]

does it knock any? if it knocks then you have an air leak somewhere.

as the others said. clean fuel and drive. report back.