Ever connect a taximeter to an IDI? WHOA!

[Andrew M. Frankli]

I found an old Pulsar Taximeter the other day and just for fun did a little research and wired it into my 93 IDI. It is a simple 3 wire system - 12v and a signal wire from VSS which in my case is a tan/blk wire near Master Cylinder. My intent would be, just for fun and to mess with my wife's head a little, connect this thing up and program it so it roughly approximated what it costs me to drive my diesel. Would be good for the kids to see the quarters rack up, as well, to get an idea of how much it costs dad to run them around...

Well, other than the fact that I need a pulse divider because the meter runs insanely high (starts at $2.25, did a 2 mile route around the 'hood and meter had run up to 13.00!), something wierd happened with my trans. and this is the reason for this post.

I don't know what the meter does with the VSS input, but there must be some sort of electrical backfeeding or wierd load it puts on the wiring because the trans shifts like I'm sidestepping a manual! I mean it, this thing shifts HARD. Won't shift till about 2500 and then this thing banged into second like NOW. Then again into third at same rpm. When it came time to shift into 4th or OD or whatever (This is an E4OD), It didn't; it just hung in third and the OD stalk light started flashing. I didn't want to toast anything, so I disconnected it at the next stop. Trans and truck run fine - no damage. The only other electrical factor is that I have a BANKS transcommand module on this trans. Trans is freshly rebuilt, too. Anyway, for what it's worth, I thought I'd share this... Sincerely, Andy

 

[Agnem]

I would definitely disconnect that feed to verify that is what is causing the problem still. Obviously the meter is going to need an interface of some kind. Why does it have to connec to the VSS?

 

[h2odrx]

I would definitely disconnect that feed to verify that is what is causing the problem still. Obviously the meter is going to need an interface of some kind. Why does it have to connec to the VSS?

It might get some input from the tranny that way?

 

[Andrew M. Frankli]

If it is not connected to the vss the meter acts like the truck is just sitting and idling (like a cab at a stoplight). When the truck starts moving, it factors in the mileage and makes the rate meter advance faster.

 

[liddledoggie]

my audiovox after market cruise control needed a special adapter to hook up to the ford speed sensor. maybe your meter needs one. joe

 

[bbressler]

Here's what I'd do:

Get you a voltmeter and see what kind of voltage/ohms the sensor is sending back to you.

Based on what you find, you can add resistors or something else to modify the current to make the speed seem lower to get your figure down.

You can put a rectifier diode between the VSS and the meter to stop any current flowing from the meter back into the tranny.