[DML] Re: Frequency valve buzzing when key in "ON" position?

["cruznmd" <racuti1@xxxxxxxxxxxx>]

Matt,

The fuel pump and frequency valve should cycle on for 1 second when 
turning the key from the "accessory" to the "run" position. The 
timer chip in the RPM relay causes this when it receives power 
during the intial key-turn. The RPM relay must receive additional 
pulses from the coil (engine turning over) to keep the contacts 
closed.

Long story short: The freq valve should not be continuously buzzing 
if the key is in "run" but the engine is off. (The idle regulator 
will though) Either the wiring was modified by a PO or perhaps your 
RPM relay is sticking. I wonder if your fuel pump is running too?

#3 injector: If ONLY the #3 injector keeps spraying after releasing 
the air-flow plate, you may have a gummed up injector. If all 
injectors keep spraying, the metering piston in the fuel distributor 
may be gummed up and doesn't move freely.

Fuel pressure: When the fuel system is pressurized, yes you should 
feel resistance when pressing on the air-flow plate. When the system 
is vented, the air-flow plate should be very free..almost bouncing 
when it pops back up. That's what the Control Pressure Regulator is 
partly for; it pushes down from the top of the metering plunger in 
the fuel distributor.

Don't think I'm nagging, but you've got to read the workshop manual. 
I studied the fuel section for 6 months until I totally understood 
the flow-diagrams and could draw the entire system (color-coded)from 
memory and I still certainly wouldn't call myself an expert.

Hope this help. Happy Holidays,

Rich A.
#5335





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