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[Solved] 1967 Firebird no gas getting to carb. How to resolve without just trying part swap?

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No gas to carburetor.

I have a 1967 Firebird 400 ci. V-8 Pontiac engine. with a mechanical fuel pump and holley 650 double pumper carburetor. The car ran fine when last started a few years ago, but will not start now as it sits. It has been garage kept for 30 years and used very little , maybe 100 miles/year or less. The engine was rebuilt less than 10000  ago in 1990. Left unknown amount of gas in tank with fuel stabilizer and lead additive. Fresh fuel probably added 3 or 4 years ago. It consumes enough fuel when running so iot hin k the gas 4 years ago was realtively fresh since i fueled it up regularly. The tank was never left full jsut whatever happened to be in the tank when parked.  Fuel pump is supposed to have a return line to tank, most new pumps do not have this so the return line is plugged. I do have a nos pump somewhere but it is ancient and was saving for a restoration. 

            Diagnosis efforts so far. : 

                 1)  The car turned over and will run when you put gas in the carburetor but stops when that little bit of gas is used up. I disconneted fuel line from carburetor

                      and turned over engine no gas getting pumped 

                 2) checked gasoline level , 18 gallon tank seemed to be empty assume it leaked out or evpaorated?, Tank had small pin hole in bottom sealed with putty,

                     weeps slightly. Losing gas has not been an issue in the past but i havent gone 2 plus years without starting it either.  I added 5 gallons of gas to tank ,

                     attempted to start car would not start. added gas to carburetor. can ran until gas rin carb was consumed. Disconnected fuel line after the pump no gas

                     getting to carb while cranking engine. 

Assume problem could be bad pump, or a pump that has lost prime (is this possible) ? or an obstruction in the line before the pump. 

What is best way to diagnose/fix? I could put on a new fuel pump but dont want to if it isnt bad. The car is in a two car attached garage and cannot be moved since a non working car ( i am fixing brakes) is currently blocking it. 

next steps? :

              1)  keep pouring gas in carb while someone else pumps gas pedal ( this shouldnt work since no gas is getting past pump). potential fire hazard.

              2) or  disconnect fuel line before pump see if gas there to rule out. I am little concerned with fire hazard of messing with gas running on ground

                   in attached garage. If i push car outside and cannot start ti i will be unable to put it in the garage again. Bad idea in rainy climate since it is a convertible. 

              3) or  Possibly apply compressed air into fuel tank with rag stuffed alongside air nozzle to slightly pressurize tank in an effort to prime pump. pour gas in carb

                  and try to get fuel pump primed. is priming even an thing with these pumps. 

               4) or swap pump without diagnoisis and just hope for the best. ( pontiac pumps i think have alittle rid in engine that drives the mecahinical pump.  cocnerned if

                  i take off pump this rod will drop down and i willbe in trouble. I dont klnow if this is an issue though just inclded it for completeness. 

 

It would seem a relatively straight forward fix as it is a simple system. The car has never done this before.  Im considering disconnecting fuel line before pump first then addressing obstruction if there is one  if gas is present there considering pressuring tank to try to prime pump. If that doesn t work try swapping fuel pump. Is any of this ill advised? Should i just jump straight to swapping pump? I could also bypass mecahnical pump and install electric fuel pump, but i dont know if that will be too much pressure for holley carb. When the car does run my clothes and hair smell like exhaust, this makes it unpleasnat to drive,  assuming carb issue ( bad power valve?) ( no exhaust leaks) and running rich, im concenred with gas diluting oil should i swap back to a quadrajet carburetor?  

 What are your thoughts on diagnising and fixing please ?

I have a new fuel tank available too on my shelf but i was just going to clean up the old fuel tank eventually and braze the hole shut. after filling it with water. I dont have the ability or tools to braze yet. though.

2 Answers
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For starters if you disconnect the fuel tank line from the pump, gas should flow from the line. If it doesn't you have an obstruction preventing fuel from getting to the pump. I suspect your fuel tank and fuel line need to be cleaned out.

If you want to go the route of an electric pump there are models specifically designed for low pressure operation suitable for carburetors.

https://www.jegs.com/i/Edelbrock/350/17301/10002/-1

thanks so much for your response.
so with electric pump , put pump close to tank and take off mechanical pump and add a blocking plate to cover up hole on engine block? and a new line to carb? wondering about that rid that may drop into my engine that dribes pump. assuming my memory is correct. hmm.

Those electric pumps are designed to be a drop-in replacement for the mechanical pump. No need to relocate it next to the tank.

One thing to be aware of is that if you hook the electric pump directly to the ignition it will keep pumping if you have an accident. You can use an oil pressure switch to cut off the pump if the engine stops due to an accident. (This link does advise to put the pump near the tank. With the Walbro electric pump I used years ago this was not necessary. Best to follow instructions that come with the pump.)

 

http://www.how-to-build-hotrods.com/electric-fuel-pump.html

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Did you disconnect the fuel line at the carb, turn the engine over and see if fuel came out?  If that's the case, it's the fuel pump.  Yes, there is a push rod that goes into place before the pump is reinstalled.

Yes i disconnected tje fuel line at carb and no fuel came out when i cranked engine. Thank you. Im also going to post another issue on my 1989 firebird this seems to be contagious.

I also ordered a new fuel pump today for the 1967 . we shall see. , i wont use it if it turns out that there is another issue between the tank and the pump.

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