I think the pumps are failing because they are cheap crap. There are a lot of manufacturers copying the old Walbro pump design. My OEM pump didn't fail after 4,000 miles, but I replaced it with a new Walbro anyway.
I took a failed pump apart... donated by Bill Fink of Isis Imports. One of the brushes had failed, most of the brush had crumbled with only a pinhead size portion making poor contact with the commutator. It was obviously a low mileage pump. The commutator was in good condition as were the bearings. There was no sign of over heating. I'll post some pictures when I figure out how to do it.
I will put a thermocouple into the fuel pump bucket to see how hot the fuel actually gets. I don't think over heating of the pump is the problem. The fuel is in contact with the hot injector bodies for a very short period of time. The fuel is constantly circulating through that area. With a fuel pressure of 58 psi in the fuel line loop, vapor lock is an impossibility.
If anybody has a failed fuel pump they want to send to me, I'll take it apart to see what failed and report.
Al Kolvites 1548 Brandywine Rd. San Mateo, California 94402
