Sorry, it's me again. Our Cummins 4BT 3.9 (VE pump) started doing this a few months ago, but stopped doing it temporarily. We cannot go beyond 1500 - 1600 rpm without getting misfiring and exhaust "popping". By popping I mean "pressure waves" of some kind. When it does this, there is NO visible smoke. At low RPM, everything seems normal, other than a little white smoke, the B7 might be a contributor here.
- The fuel filters are about 250 hrs. old and fuel can easily be pumped through them.
- The fuel pin and the AFC cone move easily and have been lubricated, while the diaphragm was replaced yesterday.
- Today, I replaced the lift pump, but the result is disappointing.
What I am thinking of now is:
1. The air filter
2. The injectors (The engine starts excellent 365 days/year, but you can never know with the Lucas, it's not THE PODs though).
3. A flat camshaft/other valve train issues??
4. A burnt or stuck valve??
5. A burnt piston (no excessive blow-by or oil consumption though).
No matter if the engine is gonna die, it's gonna kill me on its way.
- The fuel filters are about 250 hrs. old and fuel can easily be pumped through them.
- The fuel pin and the AFC cone move easily and have been lubricated, while the diaphragm was replaced yesterday.
- Today, I replaced the lift pump, but the result is disappointing.
What I am thinking of now is:
1. The air filter
2. The injectors (The engine starts excellent 365 days/year, but you can never know with the Lucas, it's not THE PODs though).
3. A flat camshaft/other valve train issues??
4. A burnt or stuck valve??
5. A burnt piston (no excessive blow-by or oil consumption though).
No matter if the engine is gonna die, it's gonna kill me on its way.
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