OBD2 to OBD1?

hankhawk · Post by **hankhawk** » Sat Sep 20, 2008 7:38 pm

Is there anyway to convert a OBD2 4g63 over to OBD1? I know most people would say "why bother" and to just get a 6 bolt. I ask the question because i have a perfectly good 7 bolt out of a 95tsi and dont want to deal with the problems that might arise in doing the swap with a OBD2 system. So im wondering if theres a way to switch it over to OBD1. Could u swap a 1g head, wiring, ecu, and misc. senors on to the block? If anyone could help me out i would greatly a apprecaite it!!!!!!!!!!!!!!!!! THANKS

jeffball610 · Post by **jeffball610** » Sat Sep 20, 2008 9:17 pm

As long as you use the 1G sensors, you should be okay. I currently have a 2G block and 1G head with a 1G wiring harness. You can run a 1G cam angle sensor on the 2G head if you want. Most of the sensors are the same from both generations, with just a difference in some wire lengths and stuff.

All you really need to get the motor running is wires for spark (coil pack, CAS etc.) O2 sensor, TB sensor, knock sensor and some temp sensors. I'm sure there's a few more, but basically that's all the wires you need along with power and ground of course.

hankhawk · Post by **hankhawk** » Sun Sep 21, 2008 11:43 pm

so i could run the 2g head with a 1g harness and ecu?

jeffball610 · Post by **jeffball610** » Mon Sep 22, 2008 3:51 am

Absolutely. Some 2G guys run a 1G CAS instead of the 2G version because it's simpler and you can adjust the timing without a diagnostic scan tool. I believe the 1G CAS puts the spark out 180 degrees, but that's not really an issue here.

You might double check my info on some of the DSM forums, but I'm almost positive the 2G head can accept a 1G CAS. The 97-99 DSMs did use a similar CAS to the 1G version, so there are provisions on that version for sure.

hankhawk · Post by **hankhawk** » Mon Sep 22, 2008 6:27 am

Anyone know what all is needed to run the 2g with the OBD1 system?

Turbotech7 · Post by **Turbotech7** » Mon Sep 22, 2008 10:23 am

if you stick with a 1g harness you could either just get a 97 + head so you dont have to drill the studs for the external cas, 95 and 96 had the cam gear CAS that is internal, after that its external. all you would need really is a 1g cas. all the sensors could be used, but doublecheck if the knock sensor is the same. i know one of them is solid and one has a hole on the thread where the sensor screws onto. other than that all you would need is (including the IDLE SW)TPS,CAS,CTS,MAF,KNK and 02 as far as the sensors go.Maybe something else too, but thats most if not all thats needed by the ecm for basic INPUTS. besides the check connections and egr temp.

jeffball610 · Post by **jeffball610** » Tue Sep 23, 2008 3:30 am

I just got confirmation from a DSM guru that the 95-96 heads do have threads in the right spot to fit the 1G CAS. Remember to use the right intake cam with the grooves made for the CAS to fit into.

hankhawk · Post by **hankhawk** » Tue Sep 23, 2008 5:52 am

From my understanding, the cam in the 2g already has the slot in it.