Home built in dash live engine monitor

[Dessertrunner]

That looks great let me know how you get on.
Tony

[Beav]

Originally Posted by Dessertrunner

I plugged the car into the subaru test unit today and looked at all the test info I think a air leak mite be the problem the O2 sensors behaved differently with one reading .02 and the other .7 when the car was crusing the numbers reveresed. I need to check them on my other SVX as they were jumping all over the place and would have thought they should have been more even and more consisdent.
Tony

That's the nature of O2 sensors. They typically switch ~1x/2sec @2000 rpm when they are in good condition. 'Switch' means crossing the 'threshold', typically figured to be .45v. .45v would be optimum, above that is rich, below is lean. The ECU changes the injector on time (in milliseconds - ms.) to accomodate the fluctuating voltage. Of course this is taking into account all other inputs are steady and nominal.

[Dessertrunner]

Beav does the ECU decide how much to inject and put the same to all injectors or does it treat each bank of the engine differently.
Tony

[svxistentialist]

Originally Posted by Dessertrunner

That looks great let me know how you get on.
Tony

Tony

Below is the reply I got. Apparently it can be made to work for some things, but it would be very costly [compared to a few gauges I suppose] using it that way. it can't be persuade to do all the things for an OBD-1 car that it can do with the OBD-11 terminal.

<<<
No. it is not OBD-I only obd-II. Technically you could hook it up
and have it read oil pressure, oil temp, and EGT, but that's would be
stupidly expensive for what would work.

Quoting Joe Devine

>
> Hi there, my question is in relation to Psi3 1-din Subaru monitor
> screen. It says all over the text, for OBD-11 Subarus. My Subaru is
> a '94 SVX and is OBD-1, with no plug socket. My question is this:
> will it work for OBD 1 cars? A secondary question would be, if it is
> not configured to read OBD-1 cars, can it be made to read sensors
> on an OBD-1 car, or would the protocol get in the way?
>
> I am strongly interested because I am supercharging my SVX
>
> Joe Devine

>>>>

So we will have to look elsewhere. Looks good, does not work good.

Joe

[Dessertrunner]

Joe our cars do have a plug to read data as I have used the Subaru reader and it provides all the function he talks about. It would be good to know if he would tell us how the data is aquired is it requested from a memory location in the ECU or what, reason being it might not be as complex to do the job our selfs.
Tony

[svxistentialist]

Originally Posted by Dessertrunner

Joe our cars do have a plug to read data as I have used the Subaru reader and it provides all the function he talks about. It would be good to know if he would tell us how the data is aquired is it requested from a memory location in the ECU or what, reason being it might not be as complex to do the job our selfs.
Tony

Tony

If your '95 car has the one colour all over, plus if it has the plug for the select monitor in the dash beside the steering column, not in the footwell, then that car could be OBD-11. Later cars are. It would work, if so.

The '92 car will have the plug in the footwell. It will be OBD-1, and won't talk to this device, the software will be wrong.

The data is acquired from the memory held in the ecu and tcu locations, same as the Subaru select monitor does.

Joe

[Dessertrunner]

Joe mine is the OBD-1 as the plug is at the foot side. I think if we can find more info then we still might be able to get into the system. The touch screen has ability to look in memory locations and get data simply by programing the unit. I will contact the guy who got into his and see what I find out. If Subaru can get in we should be able to. Found a guy in Australia who might be able to help.
Tony

[svxistentialist]

Originally Posted by Dessertrunner

Joe mine is the OBD-1 as the plug is at the foot side. I think if we can find more info then we still might be able to get into the system. The touch screen has ability to look in memory locations and get data simply by programing the unit. I will contact the guy who got into his and see what I find out. If Subaru can get in we should be able to. Found a guy in Australia who might be able to help.
Tony

Excellent. Keep me posted.

Joe

[Dessertrunner]

Joe do you recall if Lan has a program to get into the ECU?
Tony

[svxistentialist]

Sure he does.

If you bought a system from him, that includes a retuned chip, does it not?

Joe

[Dessertrunner]

Spoke to Mike and he made the plug but never got round to writing the code, have asked him about if he can help with the "how we would approach the problem".
Tony

[Beav]

Originally Posted by Dessertrunner

Beav does the ECU decide how much to inject and put the same to all injectors or does it treat each bank of the engine differently.
Tony

Well, up until the O2 sensors (and possibly the knock sensors - ask Mike/LAN) become involved it should treat both banks equally. Once those senors become a part of the equation the injectors are split by bank.

[Dessertrunner]

Beav I asked Mike and he said that the banks are managed as one they are not treated differently. Your comment before about the reading should be .45 I think my car is adjusting all the time trying to get the best mixture as one bank must be running different to the other. Next week I will unplug one O2 sensor and see if I can get the other O2 to give a stable reading.
Tony

[Beav]

Either I wasn't clear or you didn't read it correctly. The O2 voltages should be in a constant state of change. Their voltages typically rise and fall, from .1 to .9 volts, switching around once every two seconds. .45v is the 'threshold', in other words the point that separates lean from rich. Many computers use this threshold as a way of monitoring O2 sensor performance - if the voltage doesn't cross the threshold every so often it determines that a problem exists.

[svxistentialist]

Howdy Mr Master Tech.

A Happy Christmas to all in Louisville and surrounds.

Joe