Fellas, I checked YouTube to get instructions on how to remove and replace my VSS. I could not find a step by step instructional video? My problem is that my tachometer reads my Iron Duke tach revolutions all wrong! This problem began when I successfully installed the instrument gauge package from a V6 Fiero into my Duke. What sensor do I purchase and from where? Cordially, kevin
[This message has been edited by kevin (edited 03-19-2019).]
The VSS has nothing to do with the tach. It only operates the speedometer. No need to remove it for your described problem.
But, to answer your question. How to remove the VSS. Assuming it's a manual since you don't identify the transmission or year, remove the 10mm bolt on the hold-down plate. Remove the plate. There's a small notch in the side of the VSS that the hold-down plate fits into. Using a wide flat blade screwdriver, leverage the VSS upward just enough to break the seal. Then take hold of the VSS with both hands and CAREFULLY remove it by rocking it while trying to remove it as you would safely remove the cork of a bottle of champagne. Once the body of the VSS clears the transmission case, SLOWLY lift it while observing the gear on the bottom, making sure that it doesn't snag on the case. It is only just slightly smaller than the hole the VSS fits into. Drop it into the transmission and you could be in for some headaches and expense if you can't retrieve it.
Now, the second problem. Your original tach was calibrated to register 4 cylinders. The one you installed is calibrated to register 6 cylinders, so your combination will read 1/3 lower than actual rpm. At engine speed of 3000 rpm, you will be showing about 2000 rpm. You can remove the tach from your old instrument panel and swap it into your new one very easily. Just be aware that when removing the clear face plate of the instrument pod, there are two small screws hidden up underneath the top of the pod. They hold the face to the pod. Failure to remove them can break your lens.
Weren't only the 86 and later backlit? 85's were reflective. But I would bet since he said GT, he was referring to a fastback. Looking for that 120 mph speedometer.
Originally posted by fierofool: Now, the second problem. Your original tach was calibrated to register 4 cylinders. The one you installed is calibrated to register 6 cylinders, so your combination will read 1/3 lower than actual rpm. At engine speed of 3000 rpm, you will be showing about 2000 rpm. You can remove the tach from your old instrument panel and swap it into your new one very easily.
Do you happen to know where to find info on converting tachs? I have a tach with the oil pressue guage in it that I'de like to use and eliminate the center pod, I don't know if it was set up for a 4cl or 6 but if set up for a 4cl, I would like to convert it.
See olejoedad's first post. Jack Gunset in Kentucky can probably do what you need. Search memberlist for jgunsett and you can retrieve his contact info.
olejoedad, Thanks for the differentiation on my gauge cluster. I believe my cluster is from a later year Fiero. Is there a good way to identify which year Fiero gauge cluster I own? Perhaps there is an identification code that I can use? So what I understand from fierofool, I need to take my early year ‘85 Fiero gauge cluster and carefully install all my the later year cluster parts? I think I have that correct? So if I do that, the VSS remove and replace issue is no longer applicable. Correct? Cordially, kevin Ps. This would be a good time to paint my needles with a very bright orange. Maybe I can do LED bulbs......?
[This message has been edited by kevin (edited 03-20-2019).]
If the needles are illuminated with the lights on, it is 86 or newer. 120 speedo is 86 or newer. There may be differences between the flexible circuit board on the back of the cluster between the early four cylinder and later V-6, due to the use of oil pressure or voltmeter on the main instrument panel in early year Fieros. There is no real advantage to use LED in the instrument cluster. The VSS stands for Vehicle Speed Sensor, and is not relevant to the discussion, as all Fiero speedometers work with the Fiero VSS, no matter if the speedo is 85 or 120 mph. If you remove the needles to paint them, the gages may lose calibration due to the needles being reinstalled on the shaft in the wrong position. If you paint the needles on the backlit gages, the needles may no longer glow.
olejoedad, I appreciate your help regarding my tachometer issue in my ‘85 Duke 5 sp. What I am understanding is that I have to remove my newer ‘87-‘88 gauge cluster and replace it with my old ‘85 gauge ‘guts’. I will then incorporate all the newer ‘87/‘88 gauges into into my (older) ‘85 cluster. Just for clarification, my newer ‘87/‘88 tachometer reads a higher RPM not lower. In other words, at 55 mph, the ‘87/‘88 tachometer tachometer reads 4,500 at 55 mph. I’ll keep everybody up to date when I complete my retro swap. Cordially, kevin
It reads higher because it recieves three pulses per engine revolution rather than two. You may he able to use the complete 87 cluster with no issues, no need to change the guts. Forum member jgunsett can recalibrate the six cylinder tach for use with the four cylinder engine.
With eveything properly converted, I can see a potential problem with over-revving the engine past it's 4500 redline when it has a 6500 redline tach in it. It may not be a problem with the current owner if you keep that in mind, but any guest or future owner could do damage to the engine. It's pretty easy to go past the redline in the first two gears. The best solution for the tach would be to try to secure one from a late model 4 cylinder. Maybe in the mall section.
