Help Needed (electric related)

[Triple G]

So my AEM wide band uses a 0-5v output. The thing is that my 034 ecu uses a 0-1v input.

I found the following information to change the signal from 0-5v to 0-1v but don't really understand how to go about doing it.

This is what I need to do:

WB_OUT >----[XXXXX]-------[YYYYY]------< WB_OUT

Output is taken from the node where resistor XXXXX and resistor YYYYY meet.

XXXXX = 4.02K 1%, 1/4w
YYYYY = 1.00k 1%, 1/4w

Divides 5.00v to just over 1.00v

Can anyone help?

[Tuna]

Re: Help Needed (electric related)

So my AEM wide band uses a 0-5v output. The thing is that my 034 ecu uses a 0-1v input.

I found the following information to change the signal from 0-5v to 0-1v but don't really understand how to go about doing it.

This is what I need to do:


Can anyone help?

Looks like they are just dropping 4 volts across the 4k resistor. Looks like it would work without remembering my elec from 8 years ago. I guess you are measuring current (not totally sure how a wideband works) so you'd still get the fluctuation in current. Are O2 sensors really high resistance?? Because unless i'm reading it wrong you are putting the O2 in parallel with the 1k.

Edit: Simon L could probably give a much better explanation.

[Tuna]

Re: Help Needed (electric related)

I could help, I'd just need to borrow a Soldering Iron as I don't have mine anymore.

[Kordain]

Re: Help Needed (electric related)

Yeah your just dropping 4/5th of your source voltage across the 4k resistor giving you your output signal divided by 5.

Im a little concerned though that the WBOUT notations dont show polarity and therfore you dont know which way round to put the resistors in unless your diagram has a correct representation of how the termianls are laid out.

Worse instance if you couldnt figure polarity out you could just put it in and measure the voltage at the 'junction' and if your getting 1/5th of the WBOUT output then its right, if its wrong youll get 4/5ths so just swap em over.

K..

[Kordain]

Re: Help Needed (electric related)

I could help, I'd just need to borrow a Soldering Iron as I don't have mine anymore.

Id jsut try it with a temporary install first using spade connectors or simlar to ensuere you have correct polarity. If your in the south i have an iron.

[GINCH]

Re: Help Needed (electric related)

Opps, I think I just clicked on the wrong link. I was hoping to read something in english not chinese!!

[Stonewall]

Re: Help Needed (electric related)

That is just a standard voltage divider. I would have been able to wip that up in about 2 seconds at my last job as I would have had parts on hand. Phone up active electronics in the NE and see if they have those values in store (they should). Then grab the parts you need and drop by my place and I can have it done in a couple minutes for you. It would also be a good idea to pick up some heatshrink with glue in it if you plan on mounting it outside but I am sure mounting right by the gauge should be good.

[Triple G]

Re: Help Needed (electric related)

Thanks for your help

The diagram owuld be like this
From Gauge -> WB_OUT >----[XXXXX]-------[YYYYY]------< WB_OUT -> To ECU

[Mitcheh]

Re: Help Needed (electric related)

Yay!

[RobG]

Re: Help Needed (electric related)

Brent is always your electronics solution!

[Kordain]

Re: Help Needed (electric related)

Thanks for your help

The diagram owuld be like this
From Gauge -> WB_OUT >----[XXXXX]-------[YYYYY]------< WB_OUT -> To ECU

Thats good then its simple from there on, sounds like Stonewalls got you covered.

[Stonewall]

Re: Help Needed (electric related)

You will have to grab the parts though, I don't have much time too. Actually any resistor of one value with and another of 4 times the value will do but the values you posted would be ideal.

[ALEX C]

Re: Help Needed (electric related)

The only problem is with the linearity of the wide band controller. A NB O2 sensor rapidly swings from high to low voltages an your ECU interprets these as simply rich or lean. The computer can sense the amount of time that your car spends in rich or lean and extrapolate a general idea of the AFR from the duty cycle of rich vs. lean. A WBO2 has circuitry to provide a linear signal from 0-5v to represent the AFR that the circuitry is designed for. A little known fact is that you can use WBO2 on a diesel by changing the target AFR to have the 0-5 volts represent the stoichiometric ratio for diesel.
The problem with the linear scale set up in a divider circuit the stoich output would be around 0.5v. when your car is running in closed loop, it may find a .5v signal confusing and throw a code. You also need to put a resistor in to bypass the O2 sensor heater as infinate resitance will throw a code.
Here is a link that kind of explains this.
http://www.plxdevices.com/AppNotes/PLXApp004.pdf
A simple (relatively) approach would be to use 2 zener diodes to drive transistors that pull the signal high if you are rich (2.7V) or low if you are lean (2.3V). You must find out the output voltages for your particular WBO2 as they are not all the same. Most WBO2 should have a similar circuit built in to drive your narrow band sensor input.
Hope this helps.

[Triple G]

Re: Help Needed (electric related)

That is just a standard voltage divider. I would have been able to wip that up in about 2 seconds at my last job as I would have had parts on hand. Phone up active electronics in the NE and see if they have those values in store (they should). Then grab the parts you need and drop by my place and I can have it done in a couple minutes for you. It would also be a good idea to pick up some heatshrink with glue in it if you plan on mounting it outside but I am sure mounting right by the gauge should be good.

Didn't have what I needed there. Anywhere else I could try?

[Kor]

Re: Help Needed (electric related)

You could just buy a 0-1v O2 sensor?