Need help to make signal for a car ecu

[perjan6666]

hello thank you for reading.

i got a volvo that have a engine from a newer model in it, the problem is:
#Vehicle speed signal from the speedometer# its a error, not fatal but annoying,

so how do the ecu read this?
Ignition on: (Ulow/Ubat)
Idling: (Ulow/Ubat)
Driving +10km/h: 6-7V

Ulow = ~0v
Ubat = ~12v

now my problem is that this 6-7v is from the speedometer it self on the newer car, its not in my car so i need a easiest possible circuit to make this..

the speed is registered in the speedometer by counting sine waves from a tooth ring in the rear axle, i think it is sine wave not sure i will post the wiring diagram.

the circuit should be adjustable at what speed the voltage is turned down to 6-7 v

the speed sensor is the same in my car

 

[jamie_s]

the speed sender provides an AC signal to your speedometer,
the speedometer then converts the AC signal to a square wave which goes to the ecu, so you would need a device to piggyback off the speed sender and out put a square wave which you then need to connect to your ecu
im not sure where you are located, but i have suitable devices available here in australia

 

[perjan6666]

the speed sender provides an AC signal to your speedometer,
the speedometer then converts the AC signal to a square wave which goes to the ecu, so you would need a device to piggyback off the speed sender and out put a square wave which you then need to connect to your ecu
im not sure where you are located, but i have suitable devices available here in australia

why do i fint this: about the signal to the ecu if its square wave?
Ignition on: (Ulow/Ubat)
Idling: (Ulow/Ubat)
Driving +10km/h: 6-7V

Ulow = ~0v
Ubat = ~12v


do you find your device on ebay? im in Norway

 

[adamey]

What is the exact problem you're having? Is the engine performing poorly? Can you list the exact model/year/engine of your car and the car the donor engine came from?

I'm having trouble understanding the issue, since engine ECU's usually don't pay much attention the vehicle speed (except in cases where the ECU also controls an automatic transmission shift points as well).

 

[perjan6666]

What is the exact problem you're having? Is the engine performing poorly? Can you list the exact model/year/engine of your car and the car the donor engine came from?

I'm having trouble understanding the issue, since engine ECU's usually don't pay much attention the vehicle speed (except in cases where the ECU also controls an automatic transmission shift points as well).

its only a annoying error nothing fatal.

its a bosch LH 2.4
from a volvo 940 with engine B230FK

i only need a circuit to give the ecu:
Ignition on: + 12V
Idling: 0V / ground?
Driving +10km/h: 6-7V

the input to the circuit is:
ignition (+12V)
rpm of the engine from one single coil 4 cyl
wheel speed sensor

funktion of the circuit
Ignition on: + 12V output
Idling: 0V / ground? output adjustable ideling output 500 - 1000 rpm
Driving: 6-7V at + 10 km/h adjustable becase i nont know the frequency of the speed sensor at 10 kmh

circuit inputs: 3 and 10V to 15V unregulated supply
circuit output 1

 

[adamey]

The reason I wanted the year, make, model of both vehicles is so I can actually look up the wiring diagrams of both.

What's the error your getting? Is it setting a check engine light?

 

[perjan6666]

The reason I wanted the year, make, model of both vehicles is so I can actually look up the wiring diagrams of both.

What's the error your getting? Is it setting a check engine light?

i have made several of those wiringharneses from scratch the error says missing vehicle speed signal

engine from volvo 940 year 1996 b230fk engine
car volvo 240 year 1983 b21a engine
rear axle from volvo 240 year 90 with electronic speed sensor (the same as 940)

 

[perjan6666]

http://www.autoelectric.ru/auto/volvo/940/1993/940-93.htm

here you can see the wiring of this ecu number 34 is input for Vehicle speed signal. you can see the same wire on my pic in the first post

 

[perjan6666]

is it possible to feed the ac speed signal in to a Schmitt Trigger (to get 0,-1 square wave) ---> decade counter (to lower the frequency) ---> the square wave resets a sawtooth generator so if the speed is to slow it wil not reset fast enough and a transistor feed 6 - 7 regulated volt on the output.

i'm not a electric engineer and really need some help on how to connect all parts..

Thank you for reading

 

[alec_t]

Is this "6-7V" a DC level or a pulsed signal?

 

[perjan6666]

Is this "6-7V" a DC level or a pulsed signal?

its a dc signal as i can understand. i wil connect my osilliscope to a oreginal 940 and look at it

 

[alec_t]

Is your wheel speed sensor a single-ended type (one terminal grounded), or a current-loop type which connects to the ecu via a twisted-pair cable?
Is there a DC current through the sensor (as used for testing sensor integrity in ABS systems)?
Can you post a link to the sensor spec?
Can you confirm the ecu isn't expecting to receive logic-level (5V or 3V) signals rather than 12V and 6-7V?

 

[perjan6666]

Is your wheel speed sensor a single-ended type (one terminal grounded), or a current-loop type which connects to the ecu via a twisted-pair cable?
Is there a DC current through the sensor (as used for testing sensor integrity in ABS systems)?
Can you post a link to the sensor spec?
Can you confirm the ecu isn't expecting to receive logic-level (5V or 3V) signals rather than 12V and 6-7V?

look at my wiring diagram in the first post. there you see the sensor connection. and there is only one wire going to the ecu input. also on the wiring diagram on the first post