1985 pontiac fiero gt, my speedometer, odometer do not work and my fuel gauge is messed up, when it's at half a tank it's empty?

Asked by Jan 11, 2015 at 10:22 PM about the 1985 Pontiac Fiero GT

Question type: Maintenance & Repair

Could it be something with the plastic
behind the gauges, or is it something with
the governor?

1 Answer

5,955

Sounds like 3 separate issues (but maybe the speedo and odo are related). Lets start with the fuel gauge. I believe the sending unit is inside the tank and is most likely the cause but it could also be the gauge itself. The gauge responds to a voltage signal from the sender so it can be tested by applying different voltages to it. A repair manual will likely tell you what the readings should be. If it responds correctly, replace the sending unit otherwise, replace the gauge. As for the ODO, its internal, plastic gears are probably shot. If you can get a replacement gauge at a junkyard, the gears can be replaced or you may want to just replace the whole gauge and reset the milage by adjusting the gear settings. The SPEEDO could be several things but start with the sending unit somewhere in the drivetrain - I am not sure on a Fiero being it is a mid engine car, but check for a sending unit. That, when working, will translate through an electrical circuit to be read by the gauge. Any of these could be the problem and this circuit may also be driving the ODO operation as well. Good Luck.

Best Answer Mark helpful

Your Answer

Pontiac Fiero Experts

  • #1
    Andrew Welsh
    Reputation
    260
  • #2
    Steve Neyens
    Reputation
    250
  • #3
    THORNY68
    Reputation
    240
View All

Related Models For Sale

Used Pontiac Firebird
7 Great Deals out of 674 listings starting at $3,695
Used Chevrolet Camaro
224 Great Deals out of 28,922 listings starting at $3,900
Used Ford Mustang
270 Great Deals out of 37,082 listings starting at $2,150
Used Chevrolet Corvette
101 Great Deals out of 15,518 listings starting at $3,900
Used Nissan 300ZX
115 listings starting at $3,995
Used Pontiac Grand Prix
4 Great Deals out of 1,805 listings starting at $2,008
Used Toyota MR2
16 listings
Used Chevrolet Impala
397 Great Deals out of 25,595 listings starting at $799
Used Pontiac Grand Am
723 listings starting at $1,700
Used Porsche 911
69 Great Deals out of 5,013 listings starting at $11,900

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.