Upper exhaust getting hot quickly

BKENNON81

MEMBER
1994 FORD TEMPO
2.3L
4 CYL
2WD
AUTOMATIC
46,790 MILES

Within 5 minutes of driving, exhaust manifold and collector gets red hot (causing a fire one time). I checked EGR valve which is not clogged. Number three cylinder has low compression (30PSI). Excessive pressure in valve cover. Replaced PCV valve, spark plugs. Oil leaks into the air box. Exhaust doesn't seem to be clogged. Gets really hot by the O2 sensor closest to exhaust manifold. Could be head gasket but does not exchange fluids oil/coolant. Stumped

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

If you have 30 psi in the cylinder, the fuel isn't getting burned. That is allowing raw fuel to enter the exhaust which has likely damaged the catalytic converter. The raw fuel and a potentially plugged catalytic converter will certainly cause this to happen.

When you say cylinder 3 has low compression, has anything been done to try and determine the cause? For it to be that low, either we have a burnt valve, stuck rings, or a head gasket issue. To eliminate this problem, we need to first fix the compression issue. If it is a plugged converter, a new one will be damaged very quickly.

Let me know what has been done. Also, if you can take a pic of the pipe you are referring to and upload it, I may have some other ideas.

Let me know.

Joe