Hi, I'm new to the group, my name is robert and I own a stock 1990 camaro rs with 3.1 I need help with a speedo prob. I've had to buy 4
instrument clusters from salvage yards in the 5 1/2 years I've owned the car. Each time is because the small circuit board of the speedo has quit
working. I could rebuild the board but none of the intergrated circuits on the board are available and no cross reference is available. So does anyone in 3rd gen land (1) know a sorce for the circuit board used in speedo (2) know where to get the boards ic's or a working substitute ic's
(3) has a schmatic of the speedo circuit board.

 

Just in case you missed it in the other post, I wanted to be helpful here as well.

If in fact you actually DID remove the tailshaft and find a reluctor ring, then a previous owner obviously screwed with the transmission, or had it screwed with. Maybe tried using the output shaft from a 4L60E? Just speculation because I've found far too much stupidity from previous "mechanics" working on thirdgens. You've only owned the car for 5.5 years, why you think it must still be a completely stock transmission escapes me.

Anyway, if the VSS was working, as in out putting a signal, it's completely wrong. A 1990 V6 uses a '730 ECM and is expecting a 4,000 PPM ( pulse per mile ) signal. The ECM then out puts a 2000 PPM signal to the speedometer, and a 4000 PPM for the cruise control.
The reluctor ring style outputs at a much higher resolution, which is needed for ABS ( something that NO thirdgen was equipped with further proof that there is no reason any thirdgen would have the reluctor ring) it's 40 Pulses per driveshaft revolution. This equates to like 30,000+ ( rough estimate.. there is a formula if you wish to find the exact number ) Pulses Per Mile. So in fact the problem was not in 4 separate speedometers, but that the wrong signal is being used.

I used my limited knowledge of thirdgens to figure this out for you, and it only took about 30 seconds. I guess working on it for 5 and half years and not figuring it out seems reasonable too though.

 

I bought the car from a friend of mine who had owned it since new. It was the original transmission that the car was born with and had never been modified or worked on except for fluid changes. And I guess you guys at 3rd gen never got the memo that part of the car's vin number is on the transmission. As for incorrect readings,my speedo reads fne when its working, when I bought used clusters I only used the printed circuit board from the junk yard ones to bring my speedo back to life. If you would care to read the 1990 electrical schematic, you would see a real
vss in there. But of course asking you bozos on this forum to be able to read is expecting too much. And ******* ,the problem I couldn't figure out is the part #
interchange on the printed circuit board. I've had a properly working speedo the whole time I've owned the car except for those brief periods when the circuit board failed. And guess what, when you use a used part with anywhere from 160k-240 K miles ( and dumbass K means times 1000), failure will happen if part is prone to failure. Another fact you Neanderthals probably didn't pickup.

 

OK