Jeep dies on Interstate - cools and restarts???!!

[Pumpman]

Hi guys,

We have a 1986 CJ7, with a 1991 4.0 fuel injected engine. It runs super sweet almost all of the time. It starts easily, is smooth at idle and acceleration, and just generally is a great motor. However, when I try to go more than an hour away from the house by interstate, after a while it just dies as if it is out of fuel. It will not restart until it has cooled down for 10-15 minutes, then it will run perfectly for another 30 min or so until it dies again. Something is obviously overheating, but what? I do notice that the external fuel pump we use sounds unusually loud during these episodes as if it is having a hard time getting fuel, but unless it has died, it runs great. Any ideas? Thanks!

Joe

[demon67]

do you have the f-pump on a relay or drict wire?

[JCJ]

A few possibilities,

Fuel pump sounds most likely with the info given, does it have a fuel return or is it dead heading the pump? Whats the fuel tank venting look like?

Is it running on a cobbled ignition module? OEM or crappy after market spark boxes of the cj/yj vintage are pretty crappy and known for overheat/DNF function.
Fuel tank venting?