1985 Mustang GT 5.0 5-speed

RODNEYD

MEMBER
1985 FORD MUSTANG

Hello, I have a 1985 Mustang 5-speed that I'm having some problems out of. When I crank it, it has blue smoke that smells like gas coming out of the exhaust pipes bad the whole time it is running. Someone told me it is just flood smoke but I put 4 different good carburetors on it and it still does the same. I have even changed the Spark Plugs in it and it still does the same thing. And when I change the oil then it quits and it has 55 pds of oil pressure until the next day and then the oil has thinned badly and it smells like gas and my oil pressure is then down to 15 pds of oil pressure. Can you please help me? Thank you very much.

1 Reply

MHPAUTOS

MECHANIC
31,938 POSTS

Hi there,

I feel that the fuel pump may be faulty. Diaphragm pumps work on a system that allows it to stop pumping at the diaphragm when internal fuel pressure increases. This increase in fuel pressure is triggered by the needle closing at the carby float bowl when the fuel level rises the float at a predetermined position. What happens is the fuel pressure builds up and holds the diaphragm down enough so that the pump arm can still stroke with out moving the diaphragm, I feel that the pump has locked up so that it is pumping all the time, causing the flooding.

Mark (mhpautos)