Southern PA | Mike_N - 10/31/2026 06:14
You verified fuel pressure but you might want to double check that you also have volume and are not getting air in your fuel. I had an 8.3 in a truck that was sucking air through a fuel line--it looked good to the naked eye but there must have been tiny cracks in the line allowing air into the fuel stream. In this case the symptoms were lost power and lots of white, not black smoke. A good way to check is to install a piece of clear tube in the fuel line and look for air bubbles.
I had another 8.3 in a truck that lost power--it was the timing. EGT's were also shooting up under load despite the lack of power. My engine had a p-pump and on those the pump gear is a press fit, if it slips for a8ny reason the timing is thrown off. I'm not sure what injection pump they used on a 1680.
Good things to check, especially the volume vs pressure. Usually if fuel supply pressure is good, you're good. But it is possible to have normal pressure, but almost no flow.
You need to check flow as well. |
CIH 1680 Underpowered Black Smoke... I'm stumped
