Does anybody know the waveform the speedometer expects.

I'm not so much looking for the actual waveform but the amplitude range.

This is kind of advanced and I'm not sure where else to ask since the car I am working on is a M30 with an electronic speed sensor rather than a cable and it seems the car's tranny controller first receives the signal from the VSS and then sends a rather different waveform to the speedometer.

Since it never came with a manual tranny in the US, I am hoping a similar year car by nissan "conditions" the vss signal before sending it to the speedometer and it seems the maxima guys have zero mojo in this category.........so I ask here.

 

Try TwinTurbo.NET... more traffic, and I don't know the answer.

 

Never mind..............it seems it is the same as other nissans from about the late 80s to the early to mid 90s in that the signal first goes to the speedo and then to the ecu.

Apparently, all wiring diagrams out there are not correct which caused this confusion.

I do know in my experience in testing ecus for a living that many of the mid 1990s nissans like the maxima went to a scheme where the ecu first receives the signal and then it goes to the speedo.........but it's different than the input the ecu receives.

 

i've been under the impression that the vehicle speed that goes to the ecu came from different sensors (on the half shafts) than did the signal to the speedo (speed sensor in tranny). so what do you mean from the speedo to the ECU? is it causing me problems that my tranny speed sensor is out other than the speedo not working?

 

The sensors on the half shafts are for the ABS system. The ECU and speedo get their speed readings from the highest-positioned sensor on the transmission.

 

ok i see. thanks. so by that not working i guess i'm possibly missing my 150mph governor? that's the only thing i can think of that it does.

sorry for the kinda thread jack. it's very on topic though. this is my last post!

 

150mph govenor? well i've been 154.... so..... there's no such thing. =), redline in 5th gear.... 154mph... speedo meter wouldn't go any further....

 

lol ok. this argument has been had on here many times. i tend to side with the many many sources that say N/A is governed at 150. i'd love to see a source that proved it 100% one way or another. you going 154 isn't that source though. could be several things allowing that even though the car was originally governed at 150. and i'm not trying to say you're wrong. i am saying i don't know, but the material that i've read points me to believe 150. i don't plan on going that fast on the road ever, and i probably won't ever go to a track, so i'll never find out first hand.

 

Governor on both TT and NA is 155mph.

With the governor gone, mechanical top-speed of an NA (with stock wheels and tires and rev-limiter) is 167. But since any ECU that eliminates the governor also raises the rev limiter to 7450 (at least), the mechanical limit becomes 178 (but I'd venture to say that NA's don't have enough power to reach that).

And if you're missing that, it impacts steering as well... and not knowing your real speed could become annoying. TT's are impacted more, as the HICAS system requires speed input from that sensor as well.

 

it does become annoying, but i'm staying VERY safe lately since my decision to be a cop. so i just go slower than someone around.

thanks for mentioning the steering issue though. perhaps that's contributing to my steering problems. i ordered the ps pump internals i needed, but they were both on back order. the spring and flow control valve. i hope that fixes it.


i'm sorry. soo off topic. this really is my last post

 

well i was just trying to make a joke, but i guess only I got it... you can you tube like '300zx top speed' or something and there is a video of a guy going top speed in his Z, tt IIRC. what an idiot.....