Packard Forum Index » Post-War (1946-54)

Hi. As you can tell by the number of post I've done lately I'm doing some work on my 200. Here's my latest glitch, if I depress the gas peddle really quick I get a rattle that lasts for about 1 second. If I depress the gas slower there is no rattle. Any ideas?

Rattle where?? Need some sort of hint.

Is sounds like its coming from the rear of the engine or tranny

Does it happen when in park? Or only when the car is in gear and moving?

sounds like knocking....try using higher octane fuel and see if it goes away.

that is the simple check i would try first.

I know it happens in park not sure about when I'm driving.

Assuming you have looked for odd pieces of metal dangling and banging, then I might check your flex plate to converter screws. There was a rattle documented in the service bulletins from the pump selector valve on early Ultras before the introduction of the spring steel check valves--but as far as I know that can come only when the car is accelerating and the transition from front to rear pump takes place. If I recall the fix for that was--explain to the customer its supposed to do that.

try retarding the timing ever so slightly...if it goes away you can try leaving it there, or use higher octane gas.

Also, make sure your dist vacuum advance is working. Mine was and literally stopped overnight.

I would suggest checking that your carburettor accelerator pump is working properly (engine off-choke off -look down carby and operate throttle rod - you should get a good sqirt of gas from each of the pump outlets). If your accelerator pump is not working your engine mixture will be lean on rapid throttle butterfly opening and denotation may occur momentarily. That's my theory and worth a try. Peter Toet