106681-4252 ZEXEL INJECTION-PUMP ASSEMBLY Calibration Data 1066814252

The problems in this chart are problems that do come about and are normally called "low power." These problems are not necessarily more common than engine problems, but they are possible problems which you need to read and check before an engine is disassembled.Read all of the items but make sure the first four are checked completely before making any engine test. Recommended Procedure1. Tachometer Error ... To check, connect a tachometer of known accuracy to the engine. Run the engine and make a comparison of the readings of the vehicle and test tachometers. If vehicle tachometer is bad, make repairs as necessary or install a new tachometer.2. Engine Operate at High Altitude ... Less oxygen at higher altitudes causes the engine horsepower to go down. There is no effect on the horsepower of the engine for the first 7500 ft. (2280 m) above sea level of operation.3. Brakes Do Not Completely Release ... Check the brakes by feeling all the brake drums. If the brakes of a wheel do not completely release, the brake drum for that wheel will be hotter than the brake drums for the other wheels. With the truck lifted with a jack, the wheels must have free rotation when turned by hand.4. Vehicle Operated in Too High a Gear ... If the operator does not shift the truck correctly, or operates the truck in a "lug" condition (using the truck in too high a gear for engine rpm to go up as accelerator pedal is pushed farther down, or using the truck in a gear where engine rpm goes down with accelerator pedal at maximum travel), poor vehicle performance is the result.5. Extra Engine Driven Equipment ... Air compressors, hydraulic pumps, alternator, and other engine driven equipment that has damage, or that was not installed correctly, or that is not in correct adjustment, can take more horsepower to drive than expected. If necessary, disconnect the equipment and test the engine.6. Speedometer Error ... A bad speedometer does not give the correct speed or the correct indication of fuel consumption. An indication of low speed can cause the operator to feel that he has a power problem.7. Speeds Too High ... The need for more horsepower is easy to see as the speed of the vehicle is increased. This is especially true if the front of the vehicle has a large surface area. Application personnel can give you the horsepower necessary for different vehicle designs at different speeds.8. Overload on Vehicle ... Application personnel can give you the horsepower needs for different vehicles.9. High Moving Resistance ... Soft ground conditions cause a need for more horsepower. To see if the problem is the engine, test the vehicle on a surface known to be good, or test on a chassis dynamometer.10. High Wind Resistance ... The horsepower needs for a truck can be divided into two parts. Part of the horsepower is used to move the vehicle and part is used to get through