Author Topic: Isuzu Elf flat spot at 2600 RPM/4.3L 4cyl.diesel  (Read 2776 times)

dieseldave

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Isuzu Elf flat spot at 2600 RPM/4.3L 4cyl.diesel
« on: December 31, 2008, 01:13:15 AM »

     I seem to have acceleration flat spot at around 2600 to 2700 RPM. In warm weather it is noticeable until the engine is fully warmed up. In cold weather,it is more noticeable when the engine is running on the cool side(just in the normal zone on temp.gauge). When the engine fully warms up it is still quite noticeable.

     When it breaks over this 'flat spot' the engine goes like a 'bat out of hell'.

    The injection system is mechanical(looks almost like the Bosch pumps on older M-B). The truck has 10,000kms on it.

     I am wondering if the Pump Timing is out due to the initial stretching of the chain and other 'break in related' items like gears,etc.

     At first,I thought it might be the veg-oil,but then I remembered that it had this symtom last summer,before I did the veg oil conversion.

     It also seems that if the air is colder,the flat spot is more noticeable.  I thought diesels liked cold combustion air!    Anybody have any ideas?