Speedo

B

Batch21

Guest
Hi All,

Just finishing off bits and pieces before the MicraGTi-r is let loose on the streets.

However we've got a problem setting up the speedo to read. We're using a Nissan Primera P11GT Gearbox which doesn't have the same pins as the GTi-r (think the GTi-r plug has 3 in the gearbox sensor?) this one only has two.

Does anyone know how i would get it to read, otherwise i'm stuck with gps speedo
:(

would really like to know how fast i'm going to be fair :D
 
PaulB

PaulB

Member
<<---- is that the micra which the engine is in?

Blimey, hope youve done a bit of chassis strengthening??
 
B

Batch21

Guest
Err......no.....i haven't.

It's held up surprisingly well so far, it puts down quite alot of the power too.

Will be seam welding the engine bay and probably welding extra sill rails too just to build a bit of strength in case of snappage :)

Yeah, that's the Micra. SR20DET :D
 
B

Batch21

Guest
Haynes for the P11 (primera gearbox)...

Section 12B,15 - Diagram 3..

Object 25 is the speed sensor... shows 3 cables...

It says
Pin 1 is earth (black)
Pin 2 is Goes into the instrument cluster (Blue/Yellow)
Pin 3 looks like power feed (Yellow pr Yellow Black)

The clocks then spit the speedo signal out to the ECU down the Yellow/Green cable


Any idea (or has anyone got evidence) of what the 2 pins output from the gearbox sensor? If it's just power and feed then i can plumb it in and ground to anything...hypothetically?
 
B

Batch21

Guest
Does anyone have the PIN - OUT diagram then? That might help.

Basically i need to know what outputs come out of the gearbox speedo sensor and what goes in to the clocks?

Get the impression no-one has messed with this before!
 
campbellju

campbellju

Moderators
Staff member
I've messed around the instruments area before on the R but never on a micra or primera. Here is the circuit diagram for our R's, hope it helps.

BTW, bonkers project, cool idea. Will be interested to see the results. :thumbsup:

Jim
 

Attachments

B

Batch21

Guest
To me that looks like there are 2 wires coming from the speed sensor, which go to the speedometer 19&20 and one that goes from the plug section straight to the ECU?

In which case then would wire 21 to the ECU really be needed, what would this actually do? Does the ECU really need to know how fast you are going?

Basically, i currently have the Primera GT gearbox on board which i think has 3 plug outputs from the sensor, 1 is ground. Theoretically i could ground that wire out and run the two remaining wires in to the Speedo?

Unless of course that y/g wire (21) which goes to the ECU is essential?

Confussssed :)
 
campbellju

campbellju

Moderators
Staff member
Assuming ou've got a standard ECU then I think it is essential. I made it open circuit when I first got the car as a kind of cheap trackday speed de-limiter. I never used it in anger and it seemed to run fine in the low gears but I'm sure I read somewhere the car goes into some fault mode that limits revs. I might be wrong and it won't hurt to try.

Jim
 
campbellju

campbellju

Moderators
Staff member
Short version ;-)
I believe there is a fail safe mode when you remove the speed input from a standard ECU but can't be certain
 
B

Batch21

Guest
Well it get's to 70 ok and there's no ECU input at all as far as i can see lol :) Then Gearbox sensor is hanging about doing nothing and the only gauges that work are the Tacho, Fuel and Temp gauges :)

Someone's looking at it for me tomorrow.

By the way in that image, what is the S.M.J. module which the wires run through before hitting the ECU?
 
B

Batch21

Guest
Next stage in this on-going saga!

I have been speaking with a company in America, trying to resolve this speed sensor-speedo issue.

The company is called Dakotadigital and they specialise in Digital Guages and signal input/output devices.

Basically i assumed that they might be able to build a unit to convert the 3 wire output from the Primera speed sensor into a signal that is recognisable by the pulsar clocks....therefore negating the ECU completely.

They came back to me with this:

Hello, The SR20DE/T engine with a transmission that use a 3 wire sensor are in most cases a 75,000 pulse per mile setup. I am not sure what the pulse per mile is of a early 90's Nissan Transmission also am not sure what the gauge or the ECM is looking for in frequency.

So can anyone tell me the ppm of the Primera P11 GT '96 (i think!) speed sensor?
Also what frequency the Speedo gauge input should be?

Thanks all.
 
B

Batch21

Guest
Sorry, now i just need to know the ppm of a Nissan Pulsar speedo sensor and what the Speedometer looks for in terms of input signal...with this hopefully they should be able to build me a custom unit.

Thanks Guys

Merry Christmas
 
Fusion Ed

Fusion Ed

Active Member
That's kind of missing the point. Do you even know what type of sensor these are? Are they hall effect or optical? I would guess that the 3 wire is optical and the 2 wire is hall effect BUT that may be wrong.

Send both sensors to me and ill get it working for you, I would just program a micro controller to do the conversion for you.
 
B

Batch21

Guest
Ok Ed, you want me to send you the Primera Speed sensor and a GTi-r one?

Would you need the clocks too or a wiring diagram to see how it feeds in to the speedometer? Previously i think it used to feed in to the ECU and the clocks in the Pulsar, from the sensor. I'd prefer it to be a direct feed from the Sensor to the clocks...save more wiring...

Don't mind sending you both if you think that'll be enough to get it working?
 
Fusion Ed

Fusion Ed

Active Member
All I would do is make one appear to be the signal of the other as you want. Its up to you what you do with the wiring after. Drop me an email if you want to arrange this it should only take a couple of days.
 
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