data logging problem

[turbobluestreak]

my rpm signal is jumpy. My car is at idle and ever now and again the rpm signal jumps to 8K. WTF is going on here. I'm pulling the rpm from pin 3 on the ecu is this ok or could I be getting interferance from something??







oh and the rpm signal gets really jumpy when I rev the engine.


tbs

[G-E]

TBO recently answered this verbosely on z31.com

[turbobluestreak]

ok I'm lost went over to z31.com and read up on what to do. some box by the brake master cylinder. But my Z31 box is in a 280zx and I not clear. does anyone have a wiring diagram handy? Or can I pull the signal from the tach?



tbs

[Jason84NA2T]

The Z31 FSM's are available for download here:

http://carfiche.com/manuals020/cars/

I'm really not sure if the actual tach signal at the tach will work...

[turbobluestreak]

ok I moved my rpm location and still I'm getting spikes! Note I'm also running the four wire trigger if this turns out to be a problem I'll grab a three wire out of my stash and wire it up. but here is the location I moved it to if this is still wrong will some one please mark the picture and repost or send it to me.





tbs

[turbobluestreak]

I got it fixed I read up on innovatives forum and the spikes are called coil ringing and because of the low voltage that the wideband works on it needed a 10-50kohm potentiometer to adjust the resistance going in and it eliminated the spikes.





tbs

[tmbg]

did you consider using the 120 degree line of the CAS for a tach signal instead?

[turbobluestreak]

can I use that? if I can which pin was it and I'll do that








tbs

[tmbg]

On the Z31, it's the green and black wire coming off the CAS; the green/yellow wire is the one degree signal. At the ECU, pin 17 is 120 degree, pin 8 is 1 degree.

[turbobluestreak]

thanks I'll try that tonight.




tbs

[Bernardd]

8)

[turbobluestreak]

moved to pin 17 with no problems thanks guys






tbs