[NSW] Urgen advice needed. VT to VX Engine swap.

[Jplough]

Hi guys, Hoping someone can give me some advice.
I purchased a VX V6 engine and gearbox which I indend to drop into a series 1 VT.
The VX engine comes complete with the wiring loom intact that has been disconnected from the computer on the passenger side and the 3 connections on the drivers side.
I am told I must not disconnectin the wiring loom from the computer on the VT else it will loose its security settings with the engine. Therefore I should keep the original loom on the VT and disconnect all the wiring from the engine side and reconnect on the new engine else the security system will prevent the new engine from starting.

Is this correct?? I would have thought the wiring loom is just cable and doesn't have any security coding so what difference does it make if swap engines wiring loom and all.
Its a ton more work to disconnect everything from the engine side so would prefer to keep the existing wiring loom on the vx engine and simple connect to the computer and the 3 connections on the drivers side. (plu the odd 1 or 2 sensors that are not connecting to the engine and gearbox)

Can anyone please advise if this is bollocks or do I reall need to keep the existing wiring loom on the VT and disconnect everything from the engine to swap motors.

Thanks in advance.

 

[acarmody]

Thats bull, the security is from the BCM to the ECU, nothing to the engine.

I would reuse the VT wiring harness, and just block up the EGR valve that I believe your VT didn't have.

 

[Jplough]

Thanks heaps for that. I thought as much. After all, it's just a bunch of point to point copper wires. What possible difference could it make which end you disconnect them from???? But I thought best to check first as stranger things have happened. (but maybe not quite that strange).
I would rather use the VX wiring harness on the VX replacemet engine as it is all wired up and ready to go so much easir just to drop in and connect at the major connectors rather the the 10946 connections on the motor side. (well it seemed that many when I disconnected them to get the old VT motor out because I stupidly followed that advice to not disconnected from the other end) What do you think? Will this be ok?
Also I will need to google EGR valve as no idea what that is. I'm an old codger and the last engine I replaced was a 308 out of an old HQ GTS I had in my younger days. Muuuucch younger (Man I wish I still had the HQ)
Thanks heaps for you advice mate.

 

[Jplough]

Just another quick thought. Would the connection between the BCM and ECU be through the main wiring loom hence the advice may have been correct?

 

[Brett_jjj]

You only have to re establish the security link if either the ECU or BCM is replaced with another unit. Just disconnecting it wont do anything to worry it..

 

[Jplough]

Great. Thanks for the advice.. Ended up having to use original wiring loom as I discovered the VX one had a couple of melted connectors from the small engine fire which resulted from the crash that wrote it off. Also the VT wiring has one extra connection, drivers side up behind the brake booster, that the VX loom does not have. Too lazy to figure out what it is.
The other thing I didn't realise is the wiring is in 2 separate looms. The wiring from battery to starter motor, alternator etc is separate and can be connected up prior to installing the engine which saves a bit of crawling around after.
Thanks again to you both for your invaluable advice.

 

[acarmody]

So all back together and going?

 

[Jplough]

Yep. All finished yesterday. Thanks again for your advice.
Runs like new. Couldn't be happier with the way it turned out. (VX engine purrs like a kitten)
Couple of minor learning experiences. Gearbox linkage installed upside down at first.(yes i know, i'm a dumbass)
Secondly the replacement engine came with the fuel line to the injector regulator cut off rather than disconnected at that dicky connector. (done the same thing myself to get the old engine out as not familiar with those connectors). Replaced with high pressure fuel line, double clamped both ends with a tiny smear of silastic on the metal pipe. (well back from end) Hope it holds but should be ok.
Now just need to figure out how to get rid of that stupid seat belt pre tensioner warning light. Will do a quick search on here and hope to find something. (Will be back if not)
Cheers,