GM says PWM fan support is disabled in GM crate motor E67s -- now what?

[parsonsj]

I've got an LS9 crate motor in a 69 Camaro, complete with A/C pressure sensor and C6 fan controller, and I changed the crate motor fan configuration to use PWM instead of discrete.

After days of trying to figure out why that doesn't work, I called GM Powertrain today, and they told me that PWM fan control is deliberately disabled in their E67 crate motor ECMs.

Has anybody ran into that before? Is there any way to get past GM's lockout of that feature?

Any help is most appreciated!

thanks!

[DSteck]

Use a junkyard E67. The GMPP stuff sucks anyways.

[parsonsj]

So... pick up a junk yard E67, and overlay my calibration? Will I have VIN number issues?

thanks

[DSteck]

Should all work out.

[erick_e]

Saw your post at LAT-G. Replied to both

Is the PWM function disabled in the ECM, or the OS? I can't imagine the E67 ECM's having different hardware.

Can you post the tune file or compare it to a stock ZR1? What is the service number of your ECM?

[parsonsj]

Sorry I'm slow on this, but get another (non-crate) ECU, connect it to the harness, and simply write the full calibration out from my existing tune?

[parsonsj]

Yes, I can post the tune. I have no access to a C6 ZR1...

Disabling in the OS makes a lot more sense than in the hardware, I agree, and if that's true, then replacing the ECM won't help.

[parsonsj]

Tune file:

[parsonsj]

So, here's what I've learned last night/today. My E67 (GM PN 12636660) started life intended for 07-08 Hummers. I think it's true that 07-08 E67s are incompatible with OS's written for 09+ E67s.

Given that, it seems I'm stuck. Getting a later E67 and a newer OS (like from a ZR1) is beyond my current abilities, I think.

I have read that HPTuners has an OS patch to support PWM fans, but I can't seem to find any such animal.

Anyway, that's the situation as I see it. Am I wrong? Would it be doable to get GM's ZR1 tune working with my crate motor LS9 if I got a newer E67?

thanks!

[parsonsj]

OK, I've picked up an E67, pn 12633264, and I've found a ZR1 tune in the repository. Now to get the ZR1 OS flashed onto the E67. How does one do that?

Any help appreciated!

[DSteck]

I can do it (for a fee).

[Alvin]

Just a heads up.. That C6 fan controller is not all that great. If it sees a voltage dip it will shut down and not restart. We used to sell a kit for the trailblazer SS's that used that controller and it gave us fits all the time.

[Alvin]

Try this before you give up on it

John Parsons 1969 Camaro LS9 ID850 IFR PD Mins Big Table PW Min RPM VSS Fans (1).hpt

[parsonsj]

Thanks Alvin. I gave that a shot... but no joy. Any thing I can do to investigate this more?

[parsonsj]

I'm going down the salvage yard E67 path. Tonight's experiment shows that the crate motors don't read the AC pressure sensor either.

[parsonsj]

Another (related) question: does anybody have a line on the voltage vs pressure map of the GM AC refrigerant sensor (AC Delco pn 15-51258)? I've been in contact with a vendor about a standalone fan controller for AC and engine coolant temp.

I've done some googling without much luck...

[parsonsj]

Answering my own question:

AC Pressure Sensor data.jpg

[parsonsj]

Fixed. Many thanks to Dave Steck.

Net: The GMPP crate motor E67 OS does not and can not support PWM fans or AC pressure sensors. You have to use a late model passenger car E67 and OS.

[DSteck]

Did you get that ECM working? I sent the other one out today.

[parsonsj]

I got it working just an hour ago. Support gave me access to the 2.25 beta, and that works. I'll send your other one right back to you.