VSS in 1985 Toyota Pickup

Civic/Integra/etc with a K swap
poopoo
Posts: 11
Joined: Thu Nov 12, 2015 1:49 am

VSS in 1985 Toyota Pickup

Post by poopoo »

Hello I'm swapping a K24A2 into a 1985 Toyota Pickup. Is there an option to disable the VSS input or manually set the VTEC engagement speed to, for example, 0 mph?

I read on here and elsewhere that the 04 RSX VSS output from the sensor was 4 pulses per revolution and Ktuner can read this style. I found a convertor from Marlin Crawler that converts the Toyota's cable drive into a 4 pulse per revolution electrical signal. It is a 3 wire sensor like the Honda, but I don't know if it will be exactly what the Honda ECU wants to see. Do you know what the Honda ECU likes to see?
KTuner
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Re: VSS in 1985 Toyota Pickup

Post by KTuner »

Which transmission are you using? If you're using a converter that can output the same signal as the K series the ECU will not know the difference and it should be fine.
poopoo
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Joined: Thu Nov 12, 2015 1:49 am

Re: VSS in 1985 Toyota Pickup

Post by poopoo »

Sorry, that's an important detail. I'm using the truck's original transmission Toyota W52. What I found is a converter, but it is a Toyota style signal which is also 4 pulse per revolution. What I don't know is if the signal is identical in every way. It appears the Honda ECU supplies 5V to the sensor which is grounded locally, then there is a signal wire that the ECU uses to count pulses. Do you know if there is a particular pulse width that works? Is it being brought low to ground every time the trigger teeth pass by? Might just be simple enough to be interchangeable--I hope.
poopoo
Posts: 11
Joined: Thu Nov 12, 2015 1:49 am

Re: VSS in 1985 Toyota Pickup

Post by poopoo »

I forgot to ask a somewhat related question: Will the ECU be confused at all if I don't supply a countershaft speed sensor signal? I'm a little confused as to why there is a crank position sensor in addition to countershaft.

Thank you
KTuner
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Re: VSS in 1985 Toyota Pickup

Post by KTuner »

The ECU will want a speed signal. You can adjust the incoming signal in the software as well, so if your converter box can help to get it to read any signal you'll likely be able to use it to full capacity.
poopoo
Posts: 11
Joined: Thu Nov 12, 2015 1:49 am

Re: VSS in 1985 Toyota Pickup

Post by poopoo »

Yes I know the ECU wants a speed signal. Just probing this forum to see if I can learn anything more about the nature of the signal. My converter only puts out a toyota signal. It doesn't have software (just a sensor that happens to have the same pulse per rev). Are you referring to the Ktuner software?

Can anyone answer these questions?
1.) Does the ECU need the countershaft speed sensor? (The Toyota transmission does not have a countershaft speed sensor)
2.) Can the VSS input be turned off or the VTEC engagement speed set to 0 mph?


Thank you
KTuner
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Re: VSS in 1985 Toyota Pickup

Post by KTuner »

I'll state what I said in a slightly different manner, as it answers your questions.

If you can get the ECU to see any signal with your adapter you can adjust it in the KTuner software and hopefully be able to bring it to an accurate measurement. You are doing something outside of the normal with very little detail provided so I'm afraid you're just going to have to try it.

The ECU will want a signal. It can't be disabled completely. You can make VTEC engagement 0 mph.
poopoo
Posts: 11
Joined: Thu Nov 12, 2015 1:49 am

Re: VSS in 1985 Toyota Pickup

Post by poopoo »

Okay I think I understand. Got the Ktuner in the mail today so I will play around with the speed input.

One question still stands: There are 5 speed sensors sending to the ECU. 2 cams, 1 crank, "trans countershaft/input shaft" and "trans output shaft".

My theory is the countershaft one from the trans is not needed. Can anyone confirm? Seems to me that the output shaft speed is used for VSS and the countershaft one would be for transmission fault diagnosis or some such.
KTuner
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Re: VSS in 1985 Toyota Pickup

Post by KTuner »

I'm sorry, is this an Auto transmission? You didn't mention that, but now you're mentioning an extra speed sensor only used on AT.
poopoo
Posts: 11
Joined: Thu Nov 12, 2015 1:49 am

Re: VSS in 1985 Toyota Pickup

Post by poopoo »

Oh sorry, the Toyota transmission is a manual. I think my ECU is from an auto though. The TSX wiring diagram I have states that both AT and MT have the countershaft sensor in addition to the mainshaft sensor, but they are in different locations. For AT top of transmission and MT on the transmission case.
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