Fuel in oil (1 Viewer)

[vegas702]

I have a 2F engine from a 1987 FJ60 - mechanical fuel pump.

Have a problem...

Heard a knocking, and feared it was bad enough that it could be a bearing or something else. Pulled the valve cover ... nothing appeared out of place ... everything looked like it was moving properly with lubrication.
Did compression check - all cylinders were very close to identical.
Pulled the oil filter for analysis. Per engine shop - no metal found, but he oil was very watery-like and smelled like there was fuel in it. The shop concluded that the fuel broke the oil down to the point it wasn't lubricating properly -- and causing the knock.
It seems like the only cause could be a faulty diaphragm in the fuel pump. But it's brand new!!
But - I'm not a mechanic ... so I fear that when I installed it improperly and damaged it.

Anyone experience this??

 

[SteveH]

Late 2Fs (with 3 lines) require a fuel pump spacer. The knocking may have been your fuel pump disintegrating.

Also, apply a few PSI to the inlet and outlet of your fuel pump and see if it holds pressure or if it's leaking. Finally, if your engine never gets hot enough to drive off the gasoline in the oil, you can get diluted oil - although rarely enough to cause rod knock (if that's what you were hearing).

Whatever else you do, change the oil and check cold and hot oil pressure when done with any other repairs.

 

[vegas702]

I did use the spacer when I installed the pump. Sorry ... How do you test a mechanical fuel pump for leaks?

 

[brian]

iirc they have a witness hole on the bottom.