Would the Quadrajet use both electric and mechanical pump? It seems strange to me that my 305 uses both.

 

Some did, yes. The electric in tank was sort of an "uplift" pump. It fed the mechanical and was under the intentions of combating fuel boiling

 

NOTE: Factory and Dealer Installed Vapor-Lock Update In-Tank Electric Fuel-Pumps for use with Rochester Carburetor and Mechanical Fuel Pump...
are Low-Volume, Low-Pressure (3.00 Psi) Electric Fuel-Pumps ("Helper Pumps").

Not to be confused with the more conventional Standard-Volume, 5.00 Psi to 6.00 Psi Fuel-Pumps, or EFI Fuel-Pumps.

 

it fed the mechanical and was under the intentions of combating fuel boiling

 

Delete

 

As mentioned, the factory put out a dealer-installed kit, which included an in-tank electric pump, to help prevent vapor lock. In addition, all L69 cars, and all 1987 model carb'd cars, had the in-tank electric pump from the factory.

 

Not all L69 I have had two 84 L69s only one had it

 

That is probably the year they realized they had a problem. Should have said, "most L69 cars..".

 

So without removing the tank, how do I know if I have this set up on my 87? I just scrapped my 305 in lieu of a 383 stroker. My 600 CFM carburetor seems to be causing lean popping at heavier throttle. Could this electric fuel pump in the tank be the culprit since I did not Hook up my computer?

 

I would more likely guess that your lean condition is a result of tuning. What changes to the factory Jets and rods did you make when you tune to the carburetor? Did you use a wide band air fuel gauge and vacuum gauge?

 

My 1984 Trans AM with 305 has electric choke + mechanical fuel pump. Car was built for export market to Canada.

 

If there was an In-Tank Electric "Helper" Fuel Pump being used, there would have to be Electrical Power supplied to it.

There should be THREE wires going into the Fuel Tank: Pump Power, Ground, Fuel Level Signal.


-Chello III