PWM cooling fan(s) control using ECM

[gofastwclass]

Originally Posted by mikentosh

This would explain the same issue I was having earlier. I was also working with an E38 out of a Camaro. Would love to hear a response on this as we are running the setup with discrete fans on relays now and its annoying

What year Camaro?
I have a 10 SS with an E38 I'm willing to experiment on using HP Tuners as time allows.

[mikentosh]

Originally Posted by gofastwclass

What year Camaro?
I have a 10 SS with an E38 I'm willing to experiment on using HP Tuners as time allows.

Mine is out of a '13 1LE Camaro.

[andrewb70]

Originally Posted by mikentosh

Mine is out of a '13 1LE Camaro.

Mike, the signal is ground, so your volt meter needs the other side go to a hot +12v source. Are you doing that?

Andrew

[mikentosh]

Originally Posted by andrewb70

Mike, the signal is ground, so your volt meter needs the other side go to a hot +12v source. Are you doing that?

Andrew

Yup, this is how I was measuring it.

We have moved the whole motor and E38 setup into another truck and still have pin 58 with a wire tap ready, if somebody solves this. These last few comments have us considering flashing the OS on the computer over to the Corvette setup. Does anybody have pointers on how that can be accomplished with HP tuners?

[andrewb70]

If anyone needs a controller with the connector and a Yazaki connector for the power feed, send me a PM.

Andrew

[Larry R]

Quote:
Originally Posted by dontlifttoshift
We just did a Dominator in a 32 and we used a holley 500 PSI pressure transducer. This allowed us to skip the binary switch and the gm pressure sensor and do it with one sensor. We control the pwm fan and control compressor clutch engagement (high and low pressure cut off) through the ecm.

So far, it works. (End quote)

Originally I posted this under another topic, but thought it might fit better here.

I have a HP, not a Dominator, so maybe this won't work for me, also I am new at this so forgive me if I ask dumb questions. I have been pondering your solution and trying to figure out how you did this. I assume the 500PSI transducer is somehow plugged into the A/C line, presumably on the high side. The output from that transducer must somehow get into the ECU, (Inputs?), and set up to protect the A/C system in the event of too high or too low system pressure. Then is there a set point to turn on the fan, or speed it up, when the pressure reaches a particular threshold? Then is the cooling fan controlled by the ECU through a PWM for regular (or non-air conditioned) operation? If this is the set up, it would seem that some relays or diodes be necessary to prevent back feed of electricity.

Any assistance you can offer will be greatly appreciated.

Thanks, Larry

As an addendum, my '57 Chevy uses two Spal fans wired in both series and parallel, controlled by two temperature switches of different temperature values. At the lower temperature the fans come on wired in series, so they run at approximately alt speed. When the higher temperature is reached the fans which over to parallel wiring, therefore running at full speed. The trinary switch will override any operation or no operation of the fans and go to full RPM for the duration of what is commanded by the trinary switch. This system works well, but I do like the idea of a system that will keep the engine operating temperature more stable on a reduction of fan operation that is offered by using PWM. My Studebaker is still in the build up phase so it would not be that difficult to set it up with a PWM.

[dontlifttoshift]

Yep, transducer goes in the high side and becomes an input.

The wire that runs from your AC controls to the compressor also becomes an input.

Then a wire runs from the ECU to the compressor, that is an output. Also need an output from the ECU to the C6 pwm fan controller.

The output to the compressor will not run unless it sees 12v in from AC controls _and_ pressure is between 30 and 400 psi, matching Vintage Air's cutoff on their trinary.

The fan control side has been covered in this thread already.

The problem you may have with the HP is limited number of I/O available.