FiTech EFI Tuning Forum

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Change from 24 to 58

I’ve had my ultimate ls system on 3 different 24 tooth 6 litres and have had no problems.
I just put a newer 6 litre with 58 tooth and I can get it to start. I have 58 tooth sensor and I’ve changed the settings on
handheld To 58 but it don’t start. I know I got everything hooked up rite. I got no spark. Is there something I need to do because I’ve changed to a newer block. I also got the 4x timing gear on the cam. Any suggestions?

I think you need to completely load a new program into the system, not just change the settings.

That’s what i was thinking. Im lost when it comes to doing that stuff. Don’t know where to start.

I think its time to try the Holley terminator. This is getting crazy. You go nuts trying to figure out what the problem is and you are on you own. I don’t know how many times you can check a perfectly good ground and voltage to the system to try and figure out if i did something wrong only to find out its something else. Changing to a 58 tooth L96 block from a lq4 24 tooth and can’t get a straight answer on my crank sensor. There are two different types, 5volt and 12v but apparently Fitech tells me that it doesn’t matter because they run 12v. Again, try and figure it out myself.  All i know is it don’t start and i got code 36

Im in the same boat here! mine will fire and die from losing spark.


I tried putting in a 24X Crank Sensor - No Change

So I put the 58X back in and then swapped Terminals A & C on the Cam extension harness and it will now fire and stay running but is rough where i feel the Driver side is randomly misfiring - i will be calling tech support today and going through this. Hopefully i can get some answers!

I still have not been able to update this issue. i did find that my alternator wire was causing EMI so that now has been moved, however i am still experincing a Fault 41 Cam Sensor.


Cam Wiring between A & C have been swapped - yes using FItech Extension harness

Wires swapped back (A&C) and new Cam Sensor installed

Still Same issue


I would love to get this resolved before i start beating on this, just peace of mind that it will not be throwing a ton of timing at it and not show it.