driveability

Cayman LS3,
The question is can I wire in a GPS based module used to run a GPS speedometer signal directly to the EFI harness ??? I want to setup a cruse control etc.

JoshHefnerX

If I'm not mistaken the vss is some kind of pulsed signal. You could probably do it via an arduino. But it may be better to add some kind of hall-effect sensor to possibly a cv shaft..

smokeshow

iTrader: (17)

Is it possible...sure. Is it risky....also yes lol. Cool idea but it would need some fault tolerance. Losing GPS signal would be a problem if you're using it for a cruise control input.

G Atsma

.....which will happen under ANY overpass, bridge, or tunnel

SLOW SEDAN

iTrader: (13)

Not sure why you would lose a GPS signal on a bridge or overpass, but I could see a long tunnel impacting it.

OP- Which EFI are you using? I run Holleys GPS speedo and it gets a signal in my garage and hardly ever drops out on a drive. Besides general roadworthiness I use it as a traction control input as well. GPS slightly lags actual acceleration so if wheel speed ever exceeds the GPS you know to fix something.

QwkTrip

iTrader: (23)

Dakota Digital has a variety of products. Maybe give them a call and talk through options. Here's one to look in to, https://www.dakotadigital.com/index....rod/prd837.htm

G Atsma

Actually I meant going UNDER a bridge or going thru an UNDERPASS. My bad....

driveability

I'm running a GM crate LS3 and the GM controller. I did make up a diy speed sensor using a Volvo cam gear and a wheel speed sensor mounted on a drive axel. I wired it into the GM harness and it generates a signal which is slow. At 60 mph it reads about 20 mph. I could use this for cruse but since its reading so slow the cruse would not be real accurate.

JoshHefnerX

You have a picture of that cam gear?

driveability

Here ya go, I attached it to the boot shell. Really just eyeballed the cam gear at the junk yard and cut away the center, tacked it into place. I'm really thinking about converting to a Holley system with the dash as well. The car works great, I drive this thing every day.

JoshHefnerX

Doesn't look like there's any way to physically modify that to report more pulses.. I know on the pcm's there are some places to make speedo adjustments. May be able to make some adjustments in there via rear end gear changes.

Freelance-lumberjack

My 2001 pcm uses pulses per mile, designed to allow the speedo to be accurate despite using 4:10 gears or 2.73 gears and a variety of tire sizes.
If you have tunerpro or HP tuners you could set it to the appropriate number. Tunerpro tells you how to calculate it.