Signal of the speed sensor into the cruise control computer? (3 Viewers)

[ofer bruhis]

I'm trying to implement a cruse control from an 80 series (and a 1HDT/H151) into a troopy. I have all the components, but trying to get it to work, and want to verify the signal to the cruise control computer. Is 7V enough to activate it? The Combination meter has a transistor probably to buffer the signal and amplify it. I'm getting this...

 

[Malleus]

Looks like not:

No idea what "approximately 12V" actually is. This is from the EWD. Download a copy for the year of your parts; it's 4 pages long, but there is no more info there for your use than what I posted.

 

[ofer bruhis]

Looks like not:
View attachment 3459853
No idea what "approximately 12V" actually is. This is from the EWD. Download a copy for the year of your parts; it's 4 pages long, but there is no more info there for your use than what I posted.

Thanks. I have the EWD. It's not enough info.

 

[Malleus]

Yeah, that's all Toyota published.

 

[sbman]

If you look at the schematic in the EWD for the 80 series, in the combination meter section, the schematic shows a transistor to ground with a current limiting resistor on that line. The same signal on the Engine Control page is pulling that line high with some protection circuitry added in ( a diode, resistor network, PNP transistor). The combo meter is pulling the 12V from the ECU down with a transistor that is being driven by the speedo sensor signal. So you'll need a +12V pulled up signal that pulses to ground at the rate expected by the cruise control. The signal is probably called 'approximately 12V' because it's normally high with short pulses to ground which would average to something lower than 12V.

 

[ofer bruhis]

If you look at the schematic in the EWD for the 80 series, in the combination meter section, the schematic shows a transistor to ground with a current limiting resistor on that line. The same signal on the Engine Control page is pulling that line high with some protection circuitry added in ( a diode, resistor network, PNP transistor). The combo meter is pulling the 12V from the ECU down with a transistor that is being driven by the speedo sensor signal. So you'll need a +12V pulled up signal that pulses to ground at the rate expected by the cruise control. The signal is probably called 'approximately 12V' because it's normally high with short pulses to ground which would average to something lower than 12V.

Thanks. I think it's an NPN transistor, and the reason it's a bit complicated in my case is that I'm using a 91-92 80 series speed sensor that has 2 outputs (mechanical - for the speedo) and electrical (I think for the auto transmission) and it does not provide the same square wave as the 93-97 speed sensor. I just hooked a later model speed sensor and it does provide a nice 12V square wave. I'll rig a simple circuit to handle this.