Auto Elec: Toyota Tacho pulse Qs

[AustImages]

Hi all,

My 1VD into 100 conversion is almost there, got it running yesterday.

Next prob is the tacho. My 100 had a 1Hz, which I believe gets a tacho pulse from the injector pump, but not sure what the pulse is (ie: 1 per rev or 1 per injection, or??). The 1VD sends a pulse to the tacho via the ECU, but again not sure how regular the pulse is. I have been told that it's most likely the same pulse as the V8 petrol.

So, assuming the 1VD pulse is the same as the V8 petrol, does anyone know if the pulse system is the same between the 1Hz and the V8 (ie: is it + or - pulse? Voltage?) and what is the regularity of both?

Spoke to an instrument specialist who had no idea of the specific vehicles, but does have pulse converter boxes that can adapt up to 99% difference and they are stackable (ie 2 in line for 198%)

I can't use the 1VD's tacho (different scale) and I'd rather not go to all the trouble of trying to put a petrol 100's tacho in there if I can help it. My ideal solution is the converter box, but it won't be any good if the 1Hz sends a pulse for every #1cyl inject (ie RPM/2) and the 1VD sends one for every inject (ie RPMx4).

[trev1]

I thought on the 1HZ's the tacho ran off the alternator, reading the ac side of the alternator.

[AustImages]

I thought on the 1HZ's the tacho ran off the alternator, reading the ac side of the alternator.

I had heard that was the case for earlier 1Hzs, but was told this had changed to an injector pump pulse on later versions like mine. My 1Hz does have an electrical connection coming off the engine-side of the pump. But now I'm not sure...I'll cross post this in the auto elec forum.