Time to change the injection pump ?

[Cat 920 Sweden]

I`m thinking of changing the IP in my -91 6,2.
The engine idles normal but misses and smokes unburnt fuel at higher rpm. The power is low and fuelconsumption very high::(

There is suppose to be a " J- pump " with higher power than mine, is that right ?

[gmctd]

Check the intake path and the air filter - symptoms are not enough air at higher rpm.

You might also have the injectors tested, and do a quick fuel analysis, as water in fuel will also cause that, as well as dirty\old fuel

Also, the fuel return line may be blocked - pull the top off the IP and check the HPCA solenoid and the return filter if the above suggestions don't solve the problem.

[Cat 920 Sweden]

I ran it without the intake manifold and it`s the same symptoms, so it`s not an air problem...

Where do i find the return filter and what could block the return line ?

[gmctd]

Pop the top off the DB2, and all will be revealed - the HPCA solenoid and filter are internal, in the lid.

The return line could be blocked anywhere between the DB2 and the fuel tank

Pull the injectors and have them tested - poor spray pattern causes low power and black smoke.

Worn timing chainset retards the camshaft and Inj Pump, causing low power and black smoke, which is excess fuel

If none of that heals it, then you may need another IP

[GMC 2500]

If the fuel return line is blocked.
The engine will stall.

Cat 920 Sweden..

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