fuel pump: long cranking, no fuel

[DutchEdwin]

I moved along with the project. I'm getting a spark on all plugs. So that's checked ok.

As I know the fuel line to the filter in the tank is not attached to the line that goes out of the tank I need to fix that in the future. So next I did put a jerry can in front of the bumper and a fuel line runs from the jerry can to the fuel pump (jerry can stands on the ground).

I have tried two fuel pumps but both do not draw any fuel from the jerry can.

I checked the valves on both fuel pumps, and they work nice and easy.

The last fuel pump I tried was the one I took off before I started the engine job. It was working good then, but that was about 5-6 years ago.

Question

1) can a mechanical fuel pump draw fuel over a height of about 1 to 1.5 foot?

2) how long do you need to crank before the fuel pump draws fuel through the line over a length of about 3 feet. I cranked 2 minutes each time with no result.

3) Is it possible that the connections in the steel fuel line is leaking a little air in so the pump does not draw fuel?

4) Does anyone have a suggestion what can be wrong here? What does normally fail when a pump doesn't work.

Now my battery is empty, tomorrow I'll try to operate the pump by hand on the bench and see if it draws any liquid. Perhaps the diaphragm between the plates draw air so I have to seal them off.

[55 Fargo]

Prime your carb, once the engine fires to life, that fuel pump will be pumping good.........

[Joe Flanagan]

Edwin, try the suction gun that comes with a vacuum gauge. Someone posted a picture of one in the earlier thread we had going about this issue. I tried it and it worked every time. You may have to keep pulling the trigger but keep at it and as long as there's no obstruction or a serious leak somewhere, it ought to bring the fuel up.

[DutchEdwin]

Prime your carb, once the engine fires to life, that fuel pump will be pumping good.........

Is what your are saying... the cranking speed is to low for the pump to draw gas? How about when the line is full when the car did start. Will it start up then?

I do not have that kind of a vacuum pump. Where do you put it? I could try a rubber boat pump, on the suction port, attach to the fuel line that enters the carb, with a small jar in between so the fuel does not enter the pump. Then stop and reconnect the line to the carb. and start.

I did inject fuel into the line using one of those big injection things they use in hospital (do not know the English name for it), high volume one. But then I always have the line from the jerry can empty when I did put it back into the can.

[55 Fargo]

Is what your are saying... the cranking speed is to low for the pump to draw gas? How about when the line is full when the car did start. Will it start up then?

I do not have that kind of a vacuum pump. Where do you put it? I could try a rubber boat pump, on the suction port, attach to the fuel line that enters the carb, with a small jar in between so the fuel does not enter the pump. Then stop and reconnect the line to the carb. and start.

I did inject fuel into the line using one of those big injection things they use in hospital (do not know the English name for it), high volume one. But then I always have the line from the jerry can empty when I did put it back into the can.

Edwin, if you have compression, spark ,air, fuel, and the timing is close, she will fire up. I do know that I ran my car out of gas a time or 2, it would fire up much easier with a prime of gas. Just the same reason a lot of the guys need to prime some of there 6 volt flatties after they sit for a while and the gas evaporates out. Just try it, prime the carb with a bit of gas, and try and start it,the fuel pump, should pump up. Or use the vaccum pump method and pump up some gas that way. But to think the fuel pump will pump up the gas when dry, with slow cranking, just may not happen.

Now go prime the carb, and let us know what happens.........Fred

[greg g]

Take a look at the location of the outlet of the fuel tank in relationto the height of the fuel pump. In nearly all cars the bottom of the tank is pretty close to or slightly higher tha the location of the fuel pump. So the gas should pretty much reach the pump by gravity.

The standard test it to disconnet the fuel line at the carb and direct the output into a container. A clear beverage container works well. Disconnect the coil to dist primary wire ad have an assistant crank the engine.

Count the pulses of fuel going into the container. 12 strokes should give you between 8 to 12 ounces of gas in the bottle. If it doesn't, you have a problem with the pump or in the line usualy between the tank and the suction side of the pump. You can take the bottom of the pump, and check the internal screen to see if its blocked with debris.

Mechnical pumps work best a pulling fluids so getting gas from the tank to the pump shouldn't be a problem for a properly functioning pump. electric pumps work best pushing fluids which is why they are placed close to the tank.

Raising it from the pump to the carb should be no problem for a good pump, either.

[Joe Flanagan]

Edwin,

Go to your local auto parts store and look for a vacuum gauge. It should come with the gun-like contraption that was pictured earlier. It will also have an assortment of nozzles and a length of clear plastic tubing. You put the tube on the end of the gun, put a cone-shaped nozzle on the other end of the tube, insert the nozzle into your gas line (you have to press it and hold it in there) and squeeze the trigger repeatedly until you see gasoline come up into the plastic tube.

[Jim Saraceno]

There are two tools here. A vacuum pump:

And a Vacuum gauge:

If you are having fuel problems you may want to invest in both of these. They are very handy and not very expensive.

I think you need to get fuel to the pump before it will draw. If not it is only pumping air. I also think you need to have the fuel at or above the level of the pump.

Once you get the fuel to the pump then test the pump, either by the volume method as Gregg G said or by measuring the pressure with the vacuum gauge.

Good diagnostics is the always the best path to finding the problem and making the best fix.

[DutchEdwin]

I went for the vacuum pump set like Jim posted. The only one available is an expensive one (€110,=) but then it is not a plastic pump but one made out of brass. The inexpensive one is just not available here in the shops.

I'll consider if I should order the one from JC Whitney. It all depends on FedEx and customs cost if it it worth getting in from the US.

B.t.w. Jim, do you know if this gun from JC draws a good vacuum (almost to 0)?

I like the idea of injecting the fuel into the float chamber through the vent tube. Great idea. I'll look for that tube on my carb. Makes things much easier to start up.

When she runs, I'll let you know. Guess it will be next Sunday.

I'm out shopping for the proper tools.

Syringe are a standard tool in my shop for oiling and cleaning purpose. So no problem here.

[Jim Saraceno]

Jim, do you know if this gun from JC draws a good vacuum (almost to 0)?

Well I just tried mine and it pulls vacuum to about 25 inches of vacuum. I know they sell these things with extras to bleed brakes but I could never get mine to work that way. I'd just buy the pump without the extra fittings.

They're about $25 bucks and sold at most of the auto parts chains as well as Sears. The one I saw at JCWhitney has all the extra fittings and costs about $50.

Edited March 9, 2010 by Jim Saraceno

[DutchEdwin]

Jim,

Thanks for the info, I looked in The Netherlands. Called every store in a big circle around my house, They all came up with the expensive one. I did find the same one cheaper on amazon.com. I think it could turn out to be cheaper to import one from the US then buy here.

[Joe Flanagan]

Do you have a mechanic friend who would let you borrow one? Seems to me there must be a store there that sells one.

[Jim Saraceno]

If your having that much trouble finding one, maybe you could just siphon the fuel to start.

[John Reddie]

I believe that priming the carburetor like Rockwood said with some fuel will get the engine to fire up. Once the engine starts the pump will pump much faster than when the engine is just turning over. Good luck to you.

John R

[55 Fargo]

I believe that priming the carburetor like Rockwood said with some fuel will get the engine to fire up. Once the engine starts the pump will pump much faster than when the engine is just turning over. Good luck to you.

John R

I agree John, certainly would not hurt to try, I would have tried this immmediately.......Fred

[Young Ed]

I agree that should work. I've never used a vacuum pump on either my car or truck when I replaced all the lines or rebuilt the fuel pump.