Questions and Answers

POP! Goes The Muffler Q. I have a 1983 Ford E-100 Van with a 302. AT PS AC it has about 110,000 miles and I just put in a rebuilt engine. Just about everything is new or rebuilt except the carburetor, which is a two barrel. The problem I have is when you quickly remove your foot from the accelerator at highway speeds, the engine backfires severely.

I have blown three mufflers wide open (so far). This problem occurred before and after the engine change. The engine timing is set to spec. Any input would be appreciated. No big hurry, the mufflers only cost 20 bucks a pop.

Thanks,
Jerry

A. 20 bucks a pop. You made a joke. I get it. Very funny.

Well, lets see; you had the problem before the engine was replaced and continues after the engine was replaced. And the carburetor is the only thing that is the same. Hmmm... Maybe it's a bad carburetor?

Nah, I don't think so. I think the problem is with the air injection system. The air injection system provides air to the catalytic converter and exhaust manifold to help burn up excess HC and CO. During wide open throttle or during extended closed throttle operation the air from the air pump is dumped overboard to prevent backfiring.

So, the problem could be a bad Bypass/Diverter valve, bad Bypass or Diverter Solenoid. The valves are mounted on the right hand fender apron. The solenoid closest to the rear is a diverter solenoid, while the forward solenoid is a bypass solenoid. Check that all the vacuum lines are connected correctly and are in good shape.