ive got an '87 z-28 with an lg4 electric/mecanical pump set up. a few days ago i noticed that he car had a slight bog and hard starting condition that developed. now i figure changed the filter from the paper style in the quadrajet and that would solve the problem, that was a no go. so i decided to go ahead and change the mech fuel pump on the block, i go ahead and change it now low and behold i get nothing pumping from the mech. now when ive installed a block mounter mechanical pump i usually have to fight a bit with it because the pushrod would be forcing the pump arm downward to actuate the diaphragm. when i installed it this time nothing at all. i went and pulled out the pushrod and the end that rides on the eccentric on the cam was a bit galled and concave but nothing i havent seen on a 103k mile car before. could it be that the lobe that actuates the pushrod has worn away just enough to go and muck up all the works?? if this is the case besides replacing the cam would there be any other options, possibly a slightly longer pushrod to get the pump working?

 

Why do you think it's not just a bad pump?

 

oh yea, forgot the mention. i tried 2 new carter pumps no luck with them, also tried a known good pump from my friends car to see if the 2 new pumps were possibly def's. nothing at all. i was contemplating putting an electric pump up front in the mean time just to get it up and running.

 

Uhhhh, the only way you have to fight getting the pump flush is if the eccentric is on high point. If it is on the base circle the pump will slide right in. There is probably nothing wrong.