# Not sure what im doing.......help needed

Discussion in 'General Electronics Discussion' started by xxspudxx, Apr 25, 2010.

1. ### xxspudxx

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Apr 25, 2010
Sorry if im posting in the wrong section here but im completely fish out of water here. Currently building a car with a newer injection engine. This engine needs a speed signal (0v - 10v pulse) but i cant use the original sensor. So i rigged up an abs sensor and ring hoping this would work but then upon further research this only gave a frequency, which brings me here. Is it possible to turn the frequency of the abs sensor into a voltage that the ecu will understand? Hope this is making sense?

2. ### Resqueline

2,848
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Jul 31, 2009
Yes, that should be possible. Do you know know how many pulses/mile the ECM requires, and how many teeth there are on the ABS ring (+ wheel circumference)?

3. ### xxspudxx

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Apr 25, 2010
After a bit of research on ic chips i found.......

Which im guessing is the sort of thing im needing? But that diagram means nothing to me (i know nothing of this sort of thing) But im guessing depending on the ohmage going into the circuit will mean the difference in resistors etc that will need to be used?

4. ### Resqueline

2,848
2
Jul 31, 2009
Nope, that's not at all what the ECM needs..

5. ### xxspudxx

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Apr 25, 2010
Not sure on the teeth without checking, but the ecu needs an 0v - 10v pulse, sort of info is needed to help you out?

6. ### Resqueline

2,848
2
Jul 31, 2009
It depends on what the ECM uses the speed info for. Just locking up the converter or what? It usually expects a certain number of pulser per mile to do the right things.
To give it just any number of pulses that may come from the reluctor wheel is easy enough, just use a voltage comparator (like drawn in the first part of that IC - pin 1 & 8).
If it needs accurate speed info however then you may need to insert some dividing logic/counter circuit between the comparator and the ECM.
If you don't know what it needs then the ECM part number and/or car model it came from might be helpful.
A 0/10V digital pulse is what usually comes from the optical pickup circuit in the speedometer, but reluctor pickups only deliver a few mV of sine AC.