LVZ2881

Ran into a problem with my T/A. wouldnt start. checked fuel pressure, nothing. Having just bought the car, and knowing the previous owner doesnt know as much as he thinks he does, I pulled the pump. The suction line was almost completely off the pump. reattached and retightened clamps, reinserted pump, car fired right up with 41psi on gauge with key only.
When I pulled the pump, I looked in the tank, and there is fuel is the lower section (wedge shaped section) only. After reinstalling pump, gauge was pegged at past full. I thought I may have jammed the float, so pulled it and reinstalled it (Hatch mod is a god send!!). After reinstalling pump for second time, gauge reads empty.WhenI turn key on it will go up to half full, then go back to empty. Following the link on shoebox's site, I Ohm'd the connecter and am getting 0 OHMS between the purple and black wires on the harness running to the tank.

Did my sending unit go **** up? Did I reinstall it inproperly??
Any other advice?

Kevin Blown 95 TA

Maybe you lost your ground.

Injuneer

Shoebox has some info on testing the level sending unit:

http://shbox.com/1/4th_gen_tech2.html#fuel_gauge

An open circuit (nfinite resistance) will cause it to read "full", a circuit shorted to ground (0 resistance) will cause it to stay at empty. Sounds like a wiring problem.

LVZ2881

Injuneer, first of all, thanks for the reminder in the other thread.It's been quite a few years since I've used the board.

Second, If you think it's a wiring issue, can you give some idea where to look and how to test it. I freely admit wiring is not my strong suit.

Injuneer

You were working around the fuel pump. There's a multi-pin connector right over the rear axle, on the driver's side, that has the connections for the fuel pump and the level sending unit. I'd start at the harness connector, and work your way to the fuel pump assembly, looking for bare wires, a broken wire, crushed wire, etc. Maybe the harness connector is loose. You should use a multi-meter to test for continuity and shorts.

Be VERY careful around the opening in the fuel tank, if its is open, or not tightly sealed. A spark can prove fatal. Pull the pump assembly out and test it as far from the tank as you can get it. Pack the opening in the tank with rags, to limit vapor at the rear of the car.

While you have the complete assembly out of the tank, test the resistance of the level sender, and move the float through the full range of motion, watching the fuel gauge (key on of course).

LVZ2881

Thats some good advice...
Can you run me thru how to check to resistance of the sender, and what I should be looking for, numbers wise?

Injuneer

Shoebox has the resistance table in his writeup. Set the multi-meter to ohms (1X). With the harness connector off, connect the red and black probes to the two wires from the level sender. Move the float from the very bottom (1 ohm = empty) to the very top (88 ohms = full). As you move the float up and down slowly, watch for a sudden dropout (infinite ohms) or a sudden spike (0 ohms), indicating a worn spot on the sensor. If you have the correct readings, try it again, but this time shake the wires attached to the sender to see if something is loose.

If you still have the correct readings, follow Rob's (Shoebox) instructions to check the harness back to the gauge.

LVZ2881

thanks, i'll give it a shot and post up some results. maybe it will help someone else, too.