Speedometer calibration help w/ or w/o JayCar calibration unit.

[dnegative]

http://www.dakotadigital.com/index.c...rod/prd126.htm

[tanman]

Changing from automatic to manual does not introduce speedo error, only changing the diff ratio or rolling diameter will do that.

Are you running the original hall effect speed sensor or the the one that came with the auto box? they may have a different number of pulses per revolution, which could account for the error.

[MRMOPARMAN]

Changing from automatic to manual does not introduce speedo error, only changing the diff ratio or rolling diameter will do that.

Are you running the original hall effect speed sensor or the the one that came with the auto box? they may have a different number of pulses per revolution, which could account for the error.

it can if the manual gearbox used originally had a different diff ratio behind it.

[madhushankarox]

it can if the manual gearbox used originally had a different diff ratio behind it.

Yes! you are right

[madhushankarox]

Changing from automatic to manual does not introduce speedo error, only changing the diff ratio or rolling diameter will do that.

Are you running the original hall effect speed sensor or the the one that came with the auto box? they may have a different number of pulses per revolution, which could account for the error.

This sensor is different (8000 pulses per mile) and the compatible one should be 16,000 pulses per mile one.

[Xnke]

Thanks for the reply.. There is no adjustments in my PCB

Didn't read to the end of the thread, didja? Tim posted and I built/tested/debugged a speedo converter, because those adjustments don't actually do what is needed.

[tanman]

This sensor is different (8000 pulses per mile) and the compatible one should be 16,000 pulses per mile one.

why not just run the right sensor then

[tanman]

it can if the manual gearbox used originally had a different diff ratio behind it.

has the diff been changed a well?

If the diff has not changed then no it won't, because the tailshaft will still turn the same number of revolutions for a given speed.
The speed sensor measures tailshaft speed.

[Xnke]

No, it measures VSS rotations. Nissan uses gear-drive VSS sensors in RWD transmissions, you change the VSS gear to adjust for rear end gearing. The speedometer pinion gear has to match the final drive ratio OR the speedometer will have to be adjusted...albeit a less amount than the double-speed problem here.

Pre-95 Nissan RWD is generally twice as fast as Post-95, as far as VSS pulses per VSS revolution.

[tanman]

No, it measures VSS rotations. Nissan uses gear-drive VSS sensors in RWD transmissions, you change the VSS gear to adjust for rear end gearing. The speedometer pinion gear has to match the final drive ratio OR the speedometer will have to be adjusted...albeit a less amount than the double-speed problem here.

Pre-95 Nissan RWD is generally twice as fast as Post-95, as far as VSS pulses per VSS revolution.

All speed sensors are fitted to the output shaft of the gearbox = tailshaft speed = VSS

[madhushankarox]

I'm thinking to take the VSS out of the gearbox, measure its output and confirm whether it's 4 pulses per rev/ one or a 8 pulses per rev/ one.
If it's a 4 pulses one, I will buy a new 8 pules one or if it's a 8 pules one I will buy a new 16 pules one

For now, What I know exactly is:
It's a 3 wire hall effect sensor and the supply voltage is 5V. Thread is female 7/8" - 18

Whether it's 5v-12v square wave or what ever my speedometer works fine.


So, I'm thinking to get a GM-8 or GM-16 speed sender Because they have both 8 pules and 16 pulses per rev/ sensors. Thread and voltages also matches.
But the issue I got is the KEY or LINK used to rotate the sensor. Please see following photos If I can take the key out of the GM sensor and put the old one there, everything will be fine?

GM's key / link


Current one: (The link/key can be pulled out)



I'm very happy to know your ideas. Thanks guys!

[9psi eb]

I tried to detect signal by setting

- Set S1 to 2
- Set S2 to A
- Install link LK2

and it never worked for me. LK3 either

Set it to '2' ' B' and see if it detects the input signal...these correctors have a firmware issue. if 2 B works then there is a fairly simple fix

[madhushankarox]

Set it to '2' ' B' and see if it detects the input signal...these correctors have a firmware issue. if 2 B works then there is a fairly simple fix

- Set S1 to 2
- Set S2 to B


? :knock:

[9psi eb]

- Set S1 to 2
- Set S2 to B


? :knock:

yes and see if it picks up an input signal

[madhushankarox]

yes and see if it picks up an input signal

Didn't work

Btw,

I've tested my sensor and it outputs 8 pulses per rev/ so I'm going to get a 16 pulses per rev/ one soon. Hope this can fix my issue.