Fuel pump solved
Posted by bronson Wed, 09 Nov 2005 20:17:00 GMT
Brennan and I took a look a the fuel pump over the weekend. It’s trivial to diagnose when you’ve got the right tools.
The big problem? Over a year ago, I pulled the center console to install a motorized radio antenna (got rid of the worthless radio antenna embedded in the rear window heating element). When I replaced the console, I pinched a wire underneath one of the rear mounting bolts. Apparently it took a year for the bolt to wear through the insulation… Then it started blowing 10A fuses for two weeks, then it blew 30A fuses for a week, then it died for good. My fuel pump, replaced with almost 200,000 miles on it, was probably still running fine.
Two strange things remain:
The fuses would only blow when the motor was under 2000 RPM. If I could get it started without blowing the fuse, I could drive all day by keeping the engine racing. I can’t explain this at all… There should be basically no difference in voltage across the pump at 500 RPM vs 2000 RPM.
Replacing the fuel pump DID completely fix the problem for two weeks. I figure the old pump was drawing a lot more current than the new one, making it more likely to blow a fuse. But, this too seems rather strange. Short circuits can be really finicky beasts.
That explains why I was blowing the fuse so regularly. Except… wiring the pump to the dome light would have fixed this, no question. I should have been right back on the road. What happened? While replacing the fuel pump (in fading light, using a screwdriver and scissors, head spinning from the gas fumes…) I didn’t see that there was a tiny plastic cap over the outlet on the new pump. I managed to jam the cap into the fuel hose, stuffing it up for good. Brennan and I pulled the fuel filter and found that the pump works but there’s no pressure in the line. Blocked line. I would have figured this out if I’d had a fuel pressure gauge. You just can’t pull a fuel filter with a screwdriver and scissors to check. You need wrenches.
So, it was operator error. Twice. How humbling.
If I had removed that 4 cent part before I jammed it in, I would have probabably made it to Winters. At $300 for the truck and $120 for the vandalized tire, it was a pretty costly mistake. Arg! On the other hand, I loved visiting the Hills. Carter got to help fix the Rover and use tiedowns to tow things with his tricycle. It was a great weekend.
If you’re diagnosing a similar problem on a classic Plushie, I found another area that would be likely for this. There’s a big heat shield over the catalytic converter that guards the floor pan. I lose this shield regularly about every 75,000 miles. Usually the first indication that it’s gone is that the back seat carpeting melts. The inertia switch (it cuts off the fuel pump in a crash) is right next to the hot area, and the input wires are mashed right against the floor pan. If the cat gets hot enough, I could see it melting right thorugh the insulation. And it’s a needless pain to remove the switch to check on this: takes two people and the removal of the ABS computer. For a measly switch! Rover engineers really suck sometimes.
