Sunday, May 28, 2006

Cummins Diesel Engine-Troubleshooting Low Power

Cummins Diesel Engines are not invincible as with any diesel engine, the saying goes 'nothing lasts forever' . So here are some helpful tips to check out when your Cummins Diesel Engine has a low power problem.










  • Engine overloaded - accessories hanging up, brake drag etc.
  • Fuel control lever out of adjustment
  • Mechanical shut-off partially engaged
  • Slow throttle response - air/fuel tube leaking, wastegate diaphragm or plumbing damaged. Note:wastegate is attached to the turbocharger and dumps boost pressure when maximum pressures are reached.
  • High pressure fuel leak
  • Air in the fuel system
  • Fuel supply inadequate-fuel filters?
  • Lift pump malfunction
  • Oil level incorrect
  • Intake air inadequate or overheated - air filter plugged? Check aftercooler or charge air cooler for restrictions or blockage.
  • Exhaust restriction
  • Fuel temp. high - fuel heater shut-off? Restricted fuel drain manifold?
  • Poor fuel quality
  • Air leak between turbo and intake manifold
  • Exhaust leak at manifold or turbo
  • One to many injector sealing washers installed - copper washer that slides over injector tip
  • Injectors faulty - remove and test
  • Turbo inefficient - check boost pressure / approxiamately 20 psi boost pressure with guage at intake manifold.
  • Check valve clearance
  • Injection pump timing
  • Injection pump malfunction
  • Engine compression low

There you have it! Remember to check the simple things first, and the SOURCE when troubleshooting your Cummins Diesel Engine

8 comments:

Anonymous said...

We have a 36' rv with a cummins diesel engine that has begun to balk after stops. When we accelerate, nothing happens. If we pump the gas pedal, it slowly reacts and begins to move, then we are on our way until next stop. This began right after we fueled up at a flyingJ. We only had to travel 187 miles to home. So far all we have done is add a fuel additive. Is it the fuel or a larger problem?

John said...

I would definitely check the fuel. Possibly contaminated with water? Check one of your fuel filters. If so I would attempt to drain the tank and start with fresh fuel.

mavs said...

our generator ,powered by cummins engine is stalling on load,when this happensit produces black smoke.
we tried changing the fuel filters but it persists what can this be?

J. E. Whelan said...

I would check the turbo first. You have an over-fueling problem with the excessive smoke symptom.

Anonymous said...

I have a Cummings ISX EGR 550HP 15.5litre engine that is consuming more fuel than my previous cummings
The Cummings Tech say that this is normal. Is there any way to check the fuel usage as it does not change even when the trailer is empty?

J. E. Whelan said...

That seems odd if the mileage does not change unloaded? If you could run a couple of weeks and document the exact fuel to mileage ratio and keep the data right on the money you may see a slight difference. It makes sense to me that the mileage will change with a max load on board.

Chris said...

I have a 1999 ford straight truck with a cummins diesel. Intake heater and check engine lights do not come on engine cranks but will not start. Was told to clean cables to battery but still no lights. Ignition wire to seleniods does not show power when turned to on position. Could you please help.Also ignition switch in Cab has been changed

UndisputedRig said...

I have a volvo with a n14 cummin that has a problem with low power. when accelerate only goes up to 1500 rpm and looses power and never catch enough speed when switch gear. what can be the problem?