L76 e38 into Cobra Replica - Fan and Speedo Bugs.

Ive had a Cobra with a VZ L76 and E38 up and running for quite a few years now. No real issues except The fans always ran all the time, and the ecu has never generated a speed. All wiring is per standard VZ commodore except only one fan switching off the high speed fan pin (X1\17)

Did a very mild cam swap (214\222 0.56\0.56ish) and contacted the original tuner for an update. The updated tune has made the car run awful. eg. Holding at 4000rpm and then flooring it and the car just dies for half a second before launching. Tuner reckons it could be the dynamic fuel setting which he is going to update for me.

My question is about the Fans and speedo mainly. Ive researched and identified that perhaps the lack of AC compressor is sending a fault in that is making the fans run all the time, but is there anything else that could be causing this. Tuner believes it it the wiring, but it is definitely switching the fans on from the ecu as they only run when the engine is running. If there was a wiring fault Id assume they would run when the ignition was on even of the engine was not running.

The speedo is wired as per standard vz. When I piggyback off the vss wires from the gearbox (M6) I am getting a signal as the speedo is working. Is the ECU fussy on which wire is which as it is possible I have them mixed up (X1\pin71\pin72), but I havent tried swapping them over.

Ive also asked the tuner a could of times whether not having a VSS in the ECU impacts on the tune at all (helps with low speed driveability?) Would be nice to get the reverse lock out working too as I just have a manual switch on the gearshift at present.

Thanks in advance for any advice

Update - Now have the fans working. After the updated tune the fans were fixed however the car still ran terribly. After hours of researching the symptoms I convinced myself I had installed the cam one tooth off. So off with the harmonic balancer etc to check it and its all good. Degreed the cam and within 2 degrees of spec so back to the tuner who now "has to" log the car via autocal to see what is happening. Anyway the latest tune (initial tune with autocal without any logging) has the car running much better, so obviously the tuner screwed up and cost me a lot of wasted time and effort trying to diagnose.

The problem with the vehicle speed remains - no speed generated in the ECU. Without this there is no chance the reverse lock out will work. Are there any tips I can give the tuner on how this has to be set up. I have tripple checked wiring, tried swapping the 2 wires - nothing. I know there is a signal as the speedo works when piggybacked off the signal wires. Ive checked continuity fromt he ECU connector back to the gearbox - all good.

Any help greatly appreciated.

Cheers

Just incase anyone stumbles across this question and needs an answer.....

Tuner had "H0166 Transmission output shaft speed sensor" set to "no". For him, it was not obvious that that should be "Yes".

Fan were fixed I believe by switching off the A/C fault code.

Cheers