E67 unable to get tach resolution working

[2Aspire]

Car is an 86 Monte Carlo SS that uses a V8 tach. I Had a 24x LS1 PCM set to Crank, Low Res 3, High Res 3 with pull up circuit and worked perfect.

Went to E67 PCM, Operating System 12611938 and noticed tach output would not work on crank but only PWM.

When set to PWM, the tach output is about half of what it should be and no matter what I put in the High/Low resolution, 15/15 10/10 7/7 3/3 this condition does not change and I assume its because what is stated below in the Tacho parameters.

Per the following explanation below, high and low resolution values are changeable when set to crank.

{G1201} Tachometer Type: Defines the type of Tachometer used on the vehicle.
If set to PWM or Crank, the output signal is on the following:
E38 - Black connector C1, pin 48.
E67 - Blue connector C1, pin 25.
When set to 'Crank' the pulse rate is controlled by G1202 & G1203.

Was playing around with a dakota digital signal interface SGI-100BT I borrowed and verified that my tach is expecting a V8 input and works perfectly. Strangely enough this signal converter didnt work at all with the PIN 25 output but I could get my tach to work with a tap from PIN 63 Crank position sensor into this Dakota digital device.

My question is this: Am I doing something wrong that is not allowing me to get the output I expect?

As I would rather not have to pay 100.00 for a signal adaptor since I already have software to change, what I thought would be, the correct parameters to make this work.

Any help or direction would be greatly appreciated.

[efiharness]

C1-24 is used as a pullup resistor.
Connect 24 and 25 together and then to meter input. Steve

[2Aspire]

Recap and Update:

Recap:

1. My 1986 Monte Carlo SS tach previously worked perfectly with an LS1 24x PCM, pull-up circuit, Settings= Crank, resolution set to 3 Low and High.
2. Moving to E67 PCM, Operating System 12611938 noticed tach output would not work on crank but only PWM.
3. When set to PWM, the tach output is about half of what it should be with pull up circuit and no matter what I put in the High/Low resolution, 15/15 10/10 7/7 3/3 this condition does not change
4. Used a Dakota Digital Tach interface and tach would not work at all.

Update:

1. Dakota digital helped me to troubleshoot the module and had determined that the device needed to be sent in for service.
2. Dakota digital verified what I was seeing, no tach output even though I verified, through the devices diagnostic interface, there was a 4 cylinder output from my PCM. This prompted Dakota digital to re-install the software on the module which they indicated would resolve the problem with the module
3. I Installed the Dakota digital module, used their Blue Tooth IOS app to set the module to 4 Cylinder in and 8 Cylinder out.
4. Started up and Voila! Works perfectly now.

Conclusion: My configuration is hard set to 4 cylinder output and unless you have a 4 Cylinder tach, you must purchase a device to adapt.. Go figure :ranting::ranting:

FYI...Before coming here, looking for advice to correct, I was advised by a company called Speartech that this is the condition for my configuration and that I would need an adaptor for an 8 Cylinder tach.