Failed Smog Test
I have 1985 Class C Ford E350 with a 460 carberated engine. I just had the carb rebuilt and it is now running like a top. Carb is a Holley 4180 I believe. Problem is it failed its smog test today. I...
Forum Discussion
If the high HC can stem from a lean condition, let me mention that we had a 460. 1983 chassis, no Cat Converter and FL was not testing emissions. BUT it got to running lean. The EGR valve was rusted out so it actually leaked the exhaust it was trying to control. Changed it. Found out the electric mechansim that managed vacuum to the EGR diaphragam wasn't letting the vacuum bleed off at idle, so it ran awful and usually stalled. I rigged the EGR with a straight hose with a restriction in it. EGR ran OK but engine still didn't run right.
That gets me to my second point. You had your carb off and installed it with an new carb gasket like a good boy. Right? Did you also perhaps replace the gasket between your EGR mounting plate and the Intake Manifold? Ours burned through and what's worse the plate was rusted to one of the studs, so tightening the carb mounting nut did not tighten the plate to the manifold. It took me a lot of doing to get the plate free of the stud and all studs cleaned up. Then reinstalled with new plate gasket and carb gasket. Helped a lot.
That said, Intake Manifold Leaks are not uncommon on 460. Big Heavy job to change one.
That gets me to my second point. You had your carb off and installed it with an new carb gasket like a good boy. Right? Did you also perhaps replace the gasket between your EGR mounting plate and the Intake Manifold? Ours burned through and what's worse the plate was rusted to one of the studs, so tightening the carb mounting nut did not tighten the plate to the manifold. It took me a lot of doing to get the plate free of the stud and all studs cleaned up. Then reinstalled with new plate gasket and carb gasket. Helped a lot.
That said, Intake Manifold Leaks are not uncommon on 460. Big Heavy job to change one.
