Mechanical Fuel Pump

I know the answer will be go with electric fuel pump, but I'll ask anyway. I replaced the mechanical fuel pump about 2 months ago and wiped a main bearing 2 wks later. Finally got the motor in and everything swapped over. Got it into the jeep and put a painless (not so) wiring harness in and fired it up for the first time today. Only problem. The mechanical fuel pump didn't seem to be pumping anything. Removed it to make sure it was installed under the cam and put it back in. Still nothing. Grabbed an electric fuel pump out of one of the trucks at my buddies and connected it. Jeep fired right up. Left the mechanical fuel pump installed and ran the engine. Didn't seem to be pumping at all. Did I mis-install it? Or is it just bad?

 

As long as you have the rod under the cam and it is sitting correctly everything should be fine. I am assuming all lines are connected right, and no clogs are in them. If all that checks out, Mech pumps are very cheap and most local FLAPS carry them in stock. I have alwasy used mech pumps in these JEEPs with zero problem, just my .02

 

shouldn't the arm be on top of the drive cam ?
what engine ?

 

Maybe a better way is to say that the flat smooth side of the arm should be contacting the cam.

Maybe your cam is worn?

 

The fuel pump eccentric bolts to the front of the camshaft, and rides against the fuel pump arm. You should be able to remove the fuel pump, look in there, and see the eccentric. I don't think you can lose the eccentric without something else drastic happening, like the distributor drive gear falling off, or the cam gear coming off the camshaft.

Almost certainly the fuel pump isn't installed right, or else the pump is kaput, or you have some problem with the lines.

I too am in favor of the factory mechanical pump: simple, reliable, cheap.

 

The lines aren't clogged. The electric pumped through them just fine. The flat part of the arm is on the top so it would go under. I guess the question i need to answer though is, did the new engine come with the cam eccentric or no. I would assume it would, but you never know. Didn't even check that.

 

I replaced the timing set in a 302 ford one time, and at some point during installation, I knocked the locating dowel for the fuel pump eccentric into the camshaft far enough that the eccentric just spun on the cam instead of making the fuel pump work proper. Not sure if this is applicable or not, but hope it helps

 

I would remove the pump and take a look, let us know what you find
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