my 92 accord fuel pump shuts off in the heat after about 30 min. has new main relay ignition coil, cap and rotor. will not start for about 45 min and then I get about 5-10 min out of it after. anyone else have this problem. also I noticed my tach spazing out for a short time, only once.

 

Have you already checked the ground wire and wires that run along the same subharness for possible backfeeding?

 

Have not. how would I check for backfeeding, wouldn't a bad ground cause this all the time. I don't seem to have this problem on my way to work when it is cool in the mornings.

 

a bad ground can heat up due to resistance and then as it heats up add additional resistance until the electricity can no longer flow. This going with the fact it happens in the heat.

For the backfeeding just check for any wires that are both open an contacting each other.

EDIT:

Try adding a redundant ground that runs to a different location and see if that solves your problem.

 

The tach is given it's signal from the ignitor. I would swap that out with one from the junkyard and see if that fixes it. Your existing ignitor could be overheating. They have a heatsink on them but perhaps yours isn't working right.