Been a while since I did a write up. I got deep into this 24x thing since my original conversion. I have done 3 cars now, including one running the Holley Terminator X. Originally I just got my Vortec distributor adjusted so it started up easy, or got it close based on TDC or piston 1. It seems with the original 411 PCM as long as the cam sensor was on the right 180 degrees it had no problem starting/running. This worked fine for my 411 PCM, but became a big issue on the car that is running the Holley Terminator X. It seems the Terminator X is alot more sensitive to the cam/crank sync. It will run rough, or not run at all.

So with the help of a cheap oscilloscope I have figured out a consistent way to dial in the crank/cam signals.

Essentially you are doing two channels, one for the cam and one for the crank. The signals are taken from the wires, I used a standard VOM probe and pushed it into the connector. The ground from the oscilloscope just goes to any ground.

For the Cam sensor you are tapping into pin B on the cam sensor (middle one).

The Crank Sensor you are tapping into Pin C (outside non isolated one).

Set the zoom horizontal to 20ms
the voltage to 5v per line.
The easiest way for me to read it is take screenshots and see the relation, not looking at the ongoing signal. adjust then take another screenshot.

Basically you just adjust the distributor until the rising voltage point matches up to the right point on the crank signal.

Biggest part is interpreting the crank signal. For 24x there are short and long signals. The pattern for long signals are
5 long, 1 short, 3 long, 2 short, 2 long, 3 short, 1 long, 1 short, 1 long, 5 short and then back to 5 long.

You want to line it up so the cam triggers voltage right at the end of the 4th short to right before the 5 long. See the picture below for reference, stolen from google search and torquehead website.

 

24x signal

Cam sensor hookup

crank sensor hookup

Signal on occillascope

Settings

 

can the 24x ckp be used with a single pulse cam sensor? the vortec distributor is 50% duty cycle and much more forgiving if you get the cam sensor off it will still run.

 

Not with the factory LS computer, the Holley ECMs allow you to customize it many different ways.

 

This is of interest to me because I am looking at either a Holley HP, or Dominator next year. Trying to decide if I just wanna buy the Dominator because of all the extra stuff I don't need right now, but maybe want in the future. But either way its a plan for next year.

I have an LT1 swap, so I won't need to align the cam/crank. I'll just convert to a OBD2 96-97 front cover and use the factory crank sensor, with a EFI Connection cam sensor.