Haunted fuel pump

SummerSledSix · 03-11-2002, 05:22 PM

Just wanted to pass on a hard won tidbit in case some of you guys have had this experience or happen to be "in the neighborhood" -

Am getting psyched, Spring is right around the corner, and the car is ready to romp. HOWEVER, once in awhile when I go to start it, she starts up with normal gusto, then cough, sputter, die (no fuel pressure). Other times, no problems at all. Don't want this to happen on a track day... So, after going thru harnesses, fuses, and at least one relay with my trusty ohm meter, I discovered the positive side to the pump was golden, but the GROUND side had a very iffy connection at best; just depended what mood "she" was in whether the fuel pump was gonna fire or not.

Where the positive side of the fuel pump is fed by the harness, the ground side is a short wire that connects to a chassis mounted spade lug with one of those "fast-on" quick disconnects. Getting to that spade lug ain't so easy. It's welded to the passenger side wheel well, UNDER the fuel tank (naturally, I discovered all this just *after* I filled the tank).

The lug is steel, the connector is copper; I seem to remember something about dissimilar metal joints *wanting* to corrode, and corrosion I've got. Resolved the problem by cutting off the connector, soldering in an additional length, and using a crimped-on ring lug to ground the wire to a nut-and-bolt chassis connection.

Moral of the story is, if you are having weird intermittent start-and-die (or won't start at all) problems, or you happen to have the tank out, check that ground connection and make sure it's clean. I don't like fooling with fuel tanks, so I "bullet-proofed" the connection to a torque-able ground lug. Better than spending $$$ for a replacement fuel pump only to find out that the problem was a $.29 connector.

Zeke · 03-12-2002, 08:14 PM

I leaned about the ground wire the hard way. On the way back on a Sunday from a water skiing trip to the Colorado River, my '72 stopped dead on the longest stretch of dessert hiway w/o any service for 20-30 miles. After hours, we got towed into this funky little settlement apparently created soley to establish a gas station and garage with tow trucks under contract w/ the state for that section of road. We had left just after dawn in the cool, but it was 114 degrees when we unloaded the car. The mechanic says new fuel pump, have to order it, take a day.

My option is to call a cab (from hell?) and stay in the next town w/ a motel until the car is fixed. I have no tools w/ me, but I decided to poke around under the car out in the sun on the backtop at 114. FOUND that wire! I asked the same mechanic if I could borrow some pliers and buy a 2 foot piece of wire. I don't remember, but I think I actually had to give the guy a coulple bucks for this measly little piece of wire. They wern't about to give me a jack, so I rolled the car over to a curb and got a wheel up onit so I could get under. I wound the wire around what I could and the thing fired right up. And we made it back to LA that night on the patch job.

Believe it or not, I ended up in the hospital the next day due to the ordeal. I'll bet the pavement out there was 150 degrees.

SummerSledSix · 03-13-2002, 04:56 AM

What a story! I think I'll stop whining about aborted trips to the 7-11!

The fuel pump on your '72 was in the engine well, wasn't it?

Zeke · 03-13-2002, 07:58 AM

Yes, directly under the battery, which was the source of the problem.