pcmhacking.net

Hi Guys

Been a while since I have been on here... I have just started a new project and need a bit of expert help with working out a few potenial issues that I trying to work through
Currently building a new "5ltr" (well sort of....) for my VR and I am going to go back to the hydrolic Turbo 700 instead of the electronic version. I will be running an 808 ECU in it as I don't need the ECU controlling the auto anymore + will be running the 12P code in it. Just wondering if anyone has done this type of conversion before and anything I need to look out for
I have started to try and sort out the wiring and what I need and don't need for the earlier ECU and have come up with a few questions that i'm not quite sure with

1 Speedo signal - I know the speedo signals are wired up completly different between the two and not sure what is the best way to get around it?
2 BCM data link to ECU - The 808 doesn't have a link to BCM and was wondering if it will still operate ok without the comunication between the two as I still need the BCM to run all the body electrics?
3 Park/neutral/start circuit - From what I can gather is that the BCM controls the start relay in the VR (can't get hold of any BCM wiring diagrams or pinouts to confirm) and not quite sure how the 808 uses this signal as I have conflicting drawing as one has B10 going through the park/nuetral switch and to earth and the other one drawing going through the start relay to power???

Any help on these issues will be much appreciated

I have not done that conversion, but I know that if you wanted you could install one of these https://pcmhacking.net/forums/view ... f=14&t=398 in the '808 to get a proper aldl line in it, and then with $12p you can retain vats with the bcm. Then you can add a normal OBD port and just remember to turn echo on for logging and emulating.

I was going to just bypass the vats but might have to look at adding one into the 808. So if I put one of those board in the 808 it will work with the BCM and the vats enabled?

1. speedo signal is no problems. the hydraulic t700 VSS will just wire straight into the 808, move the dash speedo signal wire straight to the same pin direct to the vss (it goes to the pcm in VR auto) you are essentially wiring it the same as a VR manual. the vss is the same on a VN-VS T5 and a T700. just the 4L60E has a different VSS.

2. dont worry about it, its only vats that communicates to the bcm.

3. the only issue you will see with the start relay is it will delay about 1 second prior to acutally engaging the starter. this is becuase the bcm tries to communicate with the pcm for the vats ready to start message, which isnt there and it times out and engages anyway.


if you were to run 12p on a 082 pcm or a 808 with sxr emulator then point 2 and 3 will be moot and will function Exactly as a VR manual does.

If I set the wiring up the same as the VR manual, will the TCC lock up still work if I hook them up to A7 (TCC lock up) and B7 (Auto temp/ 4th gear) as in the VN?

Yep, but you also need to hook up the P/N wire to B10. Prob just a typo, but C7 is the 4th gear and over temp wire.

Yeah thats what I ment lol....
In the VR does the P/N wire go to the BCM?

OK, finaly got around to rewiring the VR for the 808 but have run into a major problem.... Plugged the 808 in and fitted the NVRAM with a slightly modified V111 12P BLCF (just injector size ect) and went to start it and went straight into limp home mode. Found that it had wipped the NVRAM blank so thought that I hadn't programmed it properly so did it again and verified that it had programmed correctly and as soon as I turned the ignition on it wiped it again... rechecked all the wiring, just incase a pin was installed in the wrong place and couldn't find anything wrong (not to say that there isn't still something wrong with the wiring). Dose anyone have any ideas on what could cause the NVRAM to wipe or where I could start looking?

Check the write wire soldered under the ECU PCB is correct. If its in the wrong spot it usually trashes the NVRAM as soon as the key is turned on. Can also remove the RW jumper on the NVRAM board so it wont be able to write anything and protect the NVRAM contents to confirm that the ECU is then running off the NVRAM.

will check that out but think there maybe some other issue there as I burnt the program to an EPROM and tried it but still went straight to limp home mode.
Is there anything else that may cause the NVRAM to wipe?