GP PWM - Econo/Boost gauge setup help.

[RyanD06]

Hi Legends,

Im currently fixing up some final touches on my E30 Sr20 swap. I'm a first time user of a Link ECU or any standalone ecu for that matter, so be gentle. I found the software a bit intimidating at first but I'm really getting into it now.

Below is the econo gauge (l/100km) for a standard e30 - I believe it used injector duty cycle as an input in its standard form.      What I'm looking to do is set it up as a boost gauge.

I managed to activate it with Test (PWM) and it conducted a full sweep.

From what I can establish I need to setup a GP PWM DC table. With MAP as a reference. How do I establish what duty cycle % input I would require to move the needle to each interval on the gauge and moreover how do i set this table up once know?

Any help would be much appreciated!

Cheers, Ryan.

 

 

[Confused]

Now that you know it works kind of as expected and the output is driving the gauge, you can start to fiddle with the output value, and make a note of what duty cycle gives you the desired result on the gauge.

So, I would set up a basic table with no axis values (press X):

And then just modify this single-cell table, and watch the gauge. Make it sit at a few different points, say 10, 20, 30.

 

Then, once you've written down your values, you set up your table appropriately, such as:

(Note, my configuration here is set up for metric, if you want your boost in PSI, modify the values accordingly if you're not already set into PSI mode)

[RyanD06]

Thanks for the quick reply.

Everything you showed me makes sense, no issues there.

How do i activate it at the 10%? Do my settings look correct?

I tried several different % values in the 'GP PWM 2 DC %' single cell but with no luck. Couldn't get the needle to move in small increments.

The gauge still sweeps on the test as it did before. Settings below -

[Adamw]

The activation conditions need to be true for the output to activate.  You have got the switch logic set to "Cond 1 ONLY", so to make it work for testing you need to set up Sw Parameter 1 and Sw Cond 1 to something that will return a true result.  Something like Batt voltage > 1V will do it.  

Later since you will only want the gauge to show a value when the engine is running you would change those conditions to something like RPM > 500.

[RyanD06]

Thanks for the response Adam.

So with that next step completed I now have a new issue.

"1.2" in the cell maxes out the gauge as just like a Aux Test

"1.1" in the cell brings the needle back to zero.

I had a look at the G4x E36 M50 plugin tune and the fuel economy output for that suggested 250hz.

I thought of this as my car used to run a M50 with the factory ecu and the econometer gauge worked.

with 250hz selected and "17.1" in the cell, the gauge goes back and forth non stop, "18" in the cell maxes it out.

I still cant get it to stop in the increments.

I'm Stumped! Any advice would be much appreciated.

Cheers, Ryan.

 

 

 

[Adamw]

You really need to know what signal you are trying to generate before you can try duplicating it.  You cant really just guess.  I have a vague recollection that the E30 used an injector signal for the economy gauge, so you possibly need to vary both frequency and duty cycle.  It would be best to connect a multimeter to a stock ECU to see what sort of signal is being used.  

[RyanD06]

Ill try and find someone local with an E30 who can help me! cheers for your help Adam.

[RyanD06]

FIXED! Got her working.

If anyone ends up googling how to do it here's your answer.

The instrument cluster wiring diagram above shows the solid state logic for the fuel economy gauge. While it was very basic it appears it required vehicle speed and rpm amongst others. So with the car up on jacks, running in 2nd gear, 1100 rpm and 25kp/h, i was able to start inputing the Duty Cycle as i originally wanted.

ECU output at 250hz

18.5% Duty Cycle= 4 on the gauge
20% = 10
22% = 15
23% = 16
24% = 20
25% = 23
26% = 24
27% = 26
Ill be honest and say i didn't test at other rev ranges or speeds. So there may be some more tinkering required in that regard but so far so good.

Thanks everyone for your help!