Some ideas for testing
Originally Posted by 85-F150
1985 F150, 4 speed, 4.9, Carb, single tank. Everything else works the Temp and voltage both work good. where would i buy a sender at if that is the problem?
Is your oil pressure reading high after the engine is at normal operating temp? I am asking because my fuel gauge quit working and my oil pressure now indicates the top side of the band (AL about 1:30-2:00) it was about 12:00 with the engine at operating temp before the fuel gauge quit. Am getting a 73 ohm and a 22 ohm resistor so I can do the calabration test on both gage circuits. With the 22 ohm to ground when you turn the key on the gauge should point close to straight up (between the RM in normal on the temp gauge and same range on the fuel gauge). with the 73 ohm they should point at about the 10:30 spot on the gauge (around the E on the fuel gauge and the same spot on the oil gauge). these checks will check wiring, IVR [Instrument Voltage Regulater], and gauge at the same time. Connect with power off, turn key to ACC or ON, gauge moves to correct position for resistor. If it does not move check for open in wiring, gauge, or instrument cluster printed circuit. If the gauge moves without the resister connected check wiring for short in the lead to that sender unit. If the gauge moves but is not within range replace the IVR and retest. If it still fails replace gauge.
I bounced between the two test because the only differance st where the resistor is connected, for the oil pressure gauge, or fuel gauge, it is done at there sending unit lead wire and ground.
Hope this will also help you fix you problem
1985 F150 XLT Lariat 5.8L (351w) HO, "Holly built for Motorcraft" 4bbl, C6 Transmission, 4X2 extended cab, 8 foot bed.
"Some people spend a lifetime wondering if they've made a difference, Marines don't have that problem." President Ronald Regan 1985. I think he should have ended with: "Veterans don't have that problem." But that's me. D.A.V. USAF 1976-1992.
Last edited by GhostriderI; 04-15-2012 at 06:02 PM.
Reason: More Info