Help needed with fuel pump please

[VettePaul]

Hi. Just been turning engine over with the starter after a complete rebuild.One thing I've noticed is there is NO fuel being pumped to the carb. I took the pump off and imersed a pipe into a container of fuel and pumped it with my hand...It worked, so I put it back on the car and it didn't pump I took off the feed and imersed it in the container of fuel but still never worked. All I can think is that there is a problem with the pushrod. Can't see why because it's the same one as I've always had in there.I have changed the pump to a chrome one but the lever looks exactly the same as the original. Any idea's Guys ?....VettePaul.

 

[JHL]

Paul

When you take the pump off the pushrod sometimes slides out and into the opening for the lever, the pump will still go back in place but the rod is under the lever on the pump. You have to make sure the rod is back in place when you replace the pump. If it keeps sliding out before you get the pump in place try a bit of grease on the rod, it should then stay in place while you fit the pump.

J.

 

[VettePaul]

Thanks for replying Chick, John. The rod is definately in the right place on the pump lever. I've also put my old pump back on just to try. I cranked the engine over and I had a dribble come out but nothing more. Could it be something to do with the new cam I've put in. I've heard that some of them don't have a lobe on them to work the pump rod but mine must have because as you spin the engine the rod moves up and down.............Very confused, VettePaul.

 

[JHL]

Paul,

Any smallblock cam that I have seen has an eccentric journal cast into the cam at the front to work the pushrod, my only thought being that there might be different lengths of push rods available depending on the year of engine but I wouldn`t be sure on that one.

Is this the original engine rebuilt or is it a new one all together, what cam is in it. ???

J.

 

[VettePaul]

Hi Ya John. This is really doing my head in. I spoke with Corvette Kingdom today and he said that the length of a new pushrod is 5 3/4 1nch. I've took mine out and measured it and it's the same. As far as I know the cam I bought in the States last year resembles an L-82 cam. All I've done with the block is the crank re-ground,new main and big end bearings,new rings.I've also added a pair of earlier heads and had them and the block decked.I am close on buying myself an electric pump tomorrow instead. Cheers, Paul.

 

[Jack]

Paul:
Here's a shot in the dark ... maybe your pump IS bad. Maybe when you HAND-pump it ... you are pushing the lever a longer stroke ... farther than what is normal stroke provided by the eccentric and pushrod. Maybe ???
JACK:gap

 

[Jack]

for Paul & JHL

Paul:
It seems JHL may have a cam at-the-ready ... maybe John could take a look at his cam's pump lobe ... and estimate about how far that lobe would extend the pump's pushrod? I have a new L-82 spec cam ... but it is 10 miles away at the hangar. I'll take a look tomorrow and report back/post approximate fuel pump lobe/eccentric lift.
Jack:gap

 

[JHL]

Purely by chance I have the old Edelbrock cam right in front of me and it look like approximately 3/8" throw on the pump journal, it is possible that the pump has just given up on the job purely by coincedence but isn`t that always they way of things.

J.

 

[Jack]

Gotta LOVE this place!!!! Thanks JHL ... AND SPECIAL THANKS TO ROB!!!
JACK:gap

 

[Bullitt]

Any smallblock cam that I have seen has an eccentric journal cast into the cam at the front to work the pushrod...

This may be off the subject, but this is for clarification. There are cams that are designed for EFI applications, that are developed with a electric pump in mind. Therefore, it will not have the proper eccentric to drive the pushrod for the fuel pump. The camshaft may seem to move the rod upon visual inspection, but it is not enough for the mechanical pump. When purchasing a cam, you need to make sure it fulfills whatever fuel pump needs that you have.

--Bullitt

 

[VettePaul]

Paul:
Here's a shot in the dark ... maybe your pump IS bad. Maybe when you HAND-pump it ... you are pushing the lever a longer stroke ... farther than what is normal stroke provided by the eccentric and pushrod. Maybe ???
JACK:gap

Thanks Guys. It's definately not the pump giving up because I've tried the old one back on also. Only difference is:-with the new hi-volume one there is nothing coming out of the outlet and with the old one it just dribbles out of the outlet and not spurts. Still very confused......VettePaul.

 

[JHL]

Bullit,

You are right I never gave that a thought, I havn`t had a look at a cam that was for a fuel injection small block. When was the last carb small block made, are they all fuel injected know ???

J.

 

[JHL]

Bullit,

You are right I never gave that a thought, I havn`t had a look at a cam that was for a fuel injection small block. When was the last carb small block made, are they all fuel injected know ???

J.

 

[vigman]

Cut the old pump

Make sure you wash it out with TONS of water and make a cut near the mount plate, so the lever & pivot are still intact put it back in
Observe the motion

OR find a spring that you can shove up the port to load the push rod.

Mike

 

[big al]

NO GAS

TRY TO CHECK NEXT TO THE GAS TANK THERE IS A RUBBER THAT HOOKS THE GAS LINE TO TANK OR TWO HARD LINES TOGETHER ,THE RUBBER MAY BE BAD. GETTING AIR !IT WOULD BE ON THE HIGH AREA OF THE LINE ABOVE GAS LEVALE ,UN HOOK GAS LINE AND GET A SIPHINE GIONG AT THE PUMP.PLUG LINE AND SEE IF AIR GETS IN IF IT LOOSSES SIPHONE RUBBER BAD OR HOLE IN LINE IT WOULD BE ABOVE GAS LEVALE LINE IN TANK OR GAS WOULD END UP ON FLOOR THIS DROVE ME NUTS FOUND HOLE RUBBED IN LINE FIXED OK NOW

 

[Bullitt]

John, I must admit that I have no idea when the last carbed small-block or big-block found it's way onto the Chevy production line. If I had to guess, I would say that it was probably on a truck. I never kept abreast of GM's regular production cars, so I'm not sure when the migration to TPI, TBI or MPFI became standard for all the vehciles.

--Bullitt