Fuel Guage not working

[FatNSassy]

I have a '98 SE that I put together from two salvage cars. One with a great body; bad engine and trans, the other totaled with good engine and trans. I am working through issues with the car. The engine runs great (or has). The fuel guage has never worked (is stuck in the full position), and since this is the car my 18-year-old daughter drives, I have instructed her to just fuel it each time she drives it (she does mostly short trips). I had a coil fail, so I replaced all three coils with new ones from O'Reilly Auto Parts (sorry...tight budget). That seemed to fix that problem. Recently, the car began running rough and stalled to the point of not restarting. We got the car home and I looked it over and found the plugs and plug wires were badly in need of replacement. I replaced them and this took care of the running rough. The car started and ran, but still stalls when slowing or stopping. The slowing and stopping issue sounds like it may be out of fuel. I quizzed my daughter about her driving/fueling activity and am not entirely sure that she did not run it out of fuel. Assuming that there is fuel in it (I drive truck over-the-road and have limited time to work on things at home--i have not yet checked to see if there is fuel in the car), and since the fuel guage is not working, how do I test the fuel sender and fuel pump? If I have to drop the tank to replace the fuel sending unit, might as well replace the pump while I am in there, but do not have the money to throw parts at it to find out that I have replaced parts that are not faulty.

[PLAGUE PHANTOM]

Your sender unit has failed...time to drop the tank and replace it. Might as well replace the fuel pump while your at it.

[FatNSassy]

That is what I am thinking, but is there a way to test to be sure before dropping the tank? First, to test the fuel guage/sending unit and second, to test the fuel pump, i.e., how many psi should be at the fuel rail? I have access to a fuel pressure guage. Also, if I find that these parts need replaced, what do you think about cutting an access hole in the trunk rather than dropping the tank? I would use the sheet metal that was cut out and screw it back in place and seal it.

[MattStrike]

Use a 50-250 ohm variable resistor, or a spare/junkyard sending unitdisconnect the fuel pump connector at the tank, put the resistor in place of the sending unit. turn it back and forth, watch for gauge response. Use a DMM to make sure you pick the right wires, I don't know the wire colors off the top of my head.

40+psi is usually good.


If you cut an access hole, weld a frame around it (to strengthen it back up) and make a door that can seal, water will find it's way into your trunk.

[motopsyco]

one thing people told me about when i had issues (still do) is that one of the baffles could have broke off in the tank making it starve for fuel sometimes, that wouldnt have anything to do with your guage problem though, but when mine gets at about 5 gallons left in the tank, when turning a right turn at any speed over 10mph it will stave itself of fuel, and also when I stop. Something to consider any only option then is a new tank.