Hi All!

I am trying to install a Fiero speedo into another vehicle (an older Rodeo)
The VSS on the Rodeo is 2000 PPM.

Is there an easy / safe way to convert it to 4000 ppm? The Rodeo ECM ( it has TBI EFI) will, of course, need to see the same 2000 ppm it always has.

Any help would be greatly appreciated.

TIA !

PS - please do not email me at the e-mail listed here i, i never check it anymore. if needed I can be contacted at: dsm56 at hotmail.com

Or just post here - I will keep an eye on it - thanks!

Hi,

Here is a link to a manufacturer who makes a conversion module. I've used theirs to get my Beretta transaxle to "speak Fiero."

http://www.terf.com

Good luck.

Tom

i thought the fiero was already 2000 ppm?

mike

quote Originally posted by Mike OHIO: i thought the fiero was already 2000 ppm? mike

vss on the fiero transaxle puts out 4000 ppm, the speedo, converts it to 2000 for the fiero ecm.

unfortunately the rodeo vss starts out at 2000 ppm

------------------
You're only given a little spark of madness. You mustn't lose it.

- Robin Williams

Dakota digital also makes a speedo converter www.dakotadigital.com They make a unit for about $80.

You need to multiple up so you need something like the Dakota Digital DRAC. It has the PPL circuit to multiple.

Alternately you can try this if you are handy with a solder iron.....

One the speedo cirucit board, cut the trace going to 6 of the CS8524 (this goes on to two other chips), then jumper pin 7 of the CS 8524 chip to the trace cut *from* pin 6. That will jumper around the divide by 2 circuit.

If your chips have the GM part numbers rather than the vendors, the CS8524 chip is an 8 pin chip with pins 4 and 8 going to the connector pins S and U (VSS input).

Now with 2000PPM input from the VSS the speedo will read correctly rather than requiring 4000PPM in and dividing it by 2..... or you will let all of smoke out of the chips.....

Edit: Phil beat me to it!
Edit2: Only pin 7.

[This message has been edited by TK (edited 11-09-2005).]

quote Originally posted by TK: Alternately you can try this if you are handy with a solder iron..... One the speedo cirucit board, cut the trace going to 6 of the CS8524 (this goes on to two other chips), then jumper pin 7 or 8 of the CS 8524 chip to the trace cut *from* pin 6. That will jumper around the divide by 2 circuit. If your chips have the GM part numbers rather than the vendors, the CS8524 chip is an 8 pin chip with pins 4 and 8 going to the connector pins S and U (VSS input). Now with 2000PPM input from the VSS the speedo will read correctly rather than requiring 4000PPM in and dividing it by 2..... or you will let all of smoke out of the chips..... Edit: Phil beat me to it!

I've been trying to figure out where on the board the buffered 4000 ppm is...is it pin 6 of the CS8524? You seem to understand pretty well how this board operates. I'm using the 88 board to drive my firebird gauges (has the 4000 ppm output on pin M), but I would like to modify the earlier boards to provide the buffered 4000 ppm as well. Can you help me? Thanks.

First, note Edit 2 in my post. Only pin 7 is buffered 4000, not pin 8.

On the 8524 pin 7 is buffered 4000 which goes to N on the main connector BUT some people say theirs don't have an N.

Either way, CS8524 pin 7 is buffered 4000 (before the divider) and pin 8 is buffered 2000 (after the divider). Pin 6 is the output of the /2 and it also goes to the buffer for pin 8.

I have a bunch of Fiero 86-88 speedos and they are all the same but there might be other versions so take this for what it's worth. 84-85s might be different.

TK

[This message has been edited by TK (edited 11-09-2005).]

I have been trying to get a speed sensor signal from a Fiero Transmission to my LT1 ECM on and off for nearly two years. Anyone have any Ideas?

Thanks

Rick

quote Originally posted by TK: You need to multiple up so you need something like the Dakota Digital DRAC. It has the PPL circuit to multiple. Alternately you can try this if you are handy with a solder iron..... One the speedo cirucit board, cut the trace going to 6 of the CS8524 (this goes on to two other chips), then jumper pin 7 of the CS 8524 chip to the trace cut *from* pin 6. That will jumper around the divide by 2 circuit. If your chips have the GM part numbers rather than the vendors, the CS8524 chip is an 8 pin chip with pins 4 and 8 going to the connector pins S and U (VSS input). Now with 2000PPM input from the VSS the speedo will read correctly rather than requiring 4000PPM in and dividing it by 2..... or you will let all of smoke out of the chips..... Edit: Phil beat me to it! Edit2: Only pin 7.

Thanks for the link... but I cannot find a "DRAC" ??? The only thing I found was only capble of increasing the ppm from a minimum base of 4000ppm...

I was also hoping to install a HUD in the rodeo and it needs 4000ppm also, so I do not want to change the Fiero speedo - but that is one heck of an idea - I appreciate it.

This is the unit I'm using - call them and ask them if it will work for your needs. http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=126/category_id=287/home_id=59/mode=prod/prd126.htm

quote Originally posted by KlingonFiero: Thanks for the link... but I cannot find a "DRAC" ??? The only thing I found was only capble of increasing the ppm from a minimum base of 4000ppm... I was also hoping to install a HUD in the rodeo and it needs 4000ppm also, so I do not want to change the Fiero speedo - but that is one heck of an idea - I appreciate it.

Sorry,"DRAC" is the GM term. Phil gave you the link for the Dakota Digital.

TK

quote Originally posted by Phil: This is the unit I'm using - call them and ask them if it will work for your needs. http://www.dakotadigital.com/index.cfm/page/ptype=prod uct/product_id=126/category_id=287/home_id=59/mode=prod/prd126.htm

No workie... the lowest signal input it registers is 4000ppm. After that It can produce a 2000ppm all the way up to 16kppm.

So, Still need to double the 2000ppm, if it can be done...

Thanks!

Sure it will work - configure it for a 4000 pulse input and an 8000 pulse output, that would be a input pulse doubler that way 2000 pulses will yield 4000 pulses

I agree with Phil. It should be able to handle 2k input. I can't imagine the PLL can't go that low.

quote Originally posted by TK:. On the 8524 pin 7 is buffered 4000 which goes to N on the main connector BUT some people say theirs don't have an N. Either way, CS8524 pin 7 is buffered 4000 (before the divider) and pin 8 is buffered 2000 (after the divider). Pin 6 is the output of the /2 and it also goes to the buffer for pin 8

Thanks TK I think I was the one that told you I have never seen a pin N on the speedometer. But I'll look for this pin 7. Your knowledge of this board is amzaing. Thanks again for the help.

Amazing what happens when boredom sets in.....

Hi,

The Terf module that I told you about earlier has both multiply and divide potentiometers, so it can do what you want it to do.

quote Originally posted by Tom Piantanida: Hi, The Terf module that I told you about earlier has both multiply and divide potentiometers, so it can do what you want it to do.

Hello,
Sorry, I did look at that one and then started looking at the Dakota Digital website. The "Terf" one is almost twice as much and if the Dakota one will work...
I have another email into Dakota and we will see what the response is...
Thanks!