Trying to figure out why my speedometer doesn't work.1988 Fiero GT Getrag 5 speed. 4.9 Caddy carburated and single wire HEI distributor. for this to work does it need the origional ECU? It appears to be wired but I just got this car and it is kind of crude on the wiring in the engine compartment.
theogre
DEC 10, 08:57 PM
Engine doesn't matter. Trans w/ right VSS matters.
VSS output to Speedo then Speed Out go to ECM and Cruise in Fiero.
Does trip and/or Odo work? If true then isn't vss or wiring but speedo itself.
No... quick test... OE VSS puts out AC volts. Jack a wheel, put meter on VSS then put trans in neutral and turn the wheel By Hand. Key need to be On but engine not running. Any volts then likely vss is ok. Block tires on ground so car won't move.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
[This message has been edited by theogre (edited 12-10-2020).]
LongEZ RC
DEC 10, 10:30 PM
Trying to figure out why my speedometer doesn't work.1988 Fiero GT Getrag 5 speed. 4.9 Caddy carburated and single wire HEI distributor. for this to work does it need the origional ECU? It appears to be wired but I just got this car and it is kind of crude on the wiring in the engine compartment.
I see in the wiring diagrams in the service manual where the VSS leads go to the instrument cluster printed circuit bd. I am probably wrong but there is a fused power that is shared with the radio then a lead that goes to the cruise control module and one that goes to the electro hydraulic steering module. the last one goes to the ECM through the C203 connector. This is the big question for me, I can't figure what it does or is necessary. I do not have a radio so I need to check if I have a radio fuse.
By the way thanks so much for answering my question. It has been a while since I messed with a Fiero even though I have two of them
