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