3.4 DOHC OBDII vs. OBDI
Posted: Mon Oct 30, 2017 11:45 am
All;
I have been on here a few times in the past looking for some info and been long enough that I forgot my userID and password..... I tried a search with various keywords to try to get more info before posting but I haven't been able to find the info I am looking for.
The long story is below and I hope someone can help.....
I am finally at the point where I am installing my 3.4 DOHC swap that has been sitting for way too many years. A bit of background. I bought a '95 DOHC off a fellow Calgary Fiero owner and commissioned a Penock's member to make me a 3.4 DOHC harness. I used a '91-'93 ECU with EGR delete. All made sense when I was looking at this back on '08-'09..... (Been a while....) Harness is great and the service was great during the build as well.
After getting all the pieces, I ended up being able to buy a crate '96 DOHC so ended up selling off the '95 DOHC. Again, this was all eons ago in '08-'10.
I am now at the point of installing the '96 DOHC with a Getrag 5 spd into my project car. I laid out the wiring harness this past weekend found that very little was the same for plugs etc. That is when I started digging and remembered the info I put above.... (Again, really has been a while...)
Where I am today and a long way around to asking my questions.
- '96 DOHC full engine with all sensors bought and installed for a '96 install
- the difficult 24x crank sensor is already on the engine as well.... (apparently that is an issue with getting OBDII setup on most swaps?)
- '91-'93 ECU and engine harness
- 5 spd Getrag transmission
- I was reading that it was only possible to do an auto swap with OBDII?
- Updated fuel pump in tank and ready to be put back into the car.
- Battery relocate up front with 1 gauge cables coming back into engine bay ready to power up system
All sitting on the cradle ready to go.
Questions:
1. Does it make sense to get a new harness built that allows for ODBII as now it is much more refined than back when these were first talked about?
a. In reading old posts, the '96 has SFI not batch injector operation but only up to 3000 rpm when it switches to batch
b. I have two O2 sensors and several other additional sensors that would not be needed with a '91-'93 ECU
2. If I am to get a new harness, who makes one and what else do I need to do to the car/engine to install the OBDII vs. OBDI?
3. Are there significant issues that crop up when doing an ODBII install compared to the OBDI?
4. Just to muddy the waters a bit more, would OBD 1.5 be a better option for me since I already have the sensors that would connect to that setup and still give me SFI???
Realistically, staying with the '91-'93 harness would be a bit cheaper but I do want to do this the right way all along as this project car has been a work of love for a while now....
Hopefully someone can help me out here. I am agnostic on which way to go as I have to spend some money to either get a new harness or go return and purchase my '91-'93 senors that will work with the harness.
Thanks
Don
A pic of the car the engine and trans are going into a pic of the engine trans setup.
[img]https://i.imgur.com/Iynl7On.jpg[/img]
[img]https://i.imgur.com/y5k19Kz.jpg[/img]
[img]https://i.imgur.com/3FBpjeS.jpg[/img]
I have been on here a few times in the past looking for some info and been long enough that I forgot my userID and password..... I tried a search with various keywords to try to get more info before posting but I haven't been able to find the info I am looking for.
The long story is below and I hope someone can help.....
I am finally at the point where I am installing my 3.4 DOHC swap that has been sitting for way too many years. A bit of background. I bought a '95 DOHC off a fellow Calgary Fiero owner and commissioned a Penock's member to make me a 3.4 DOHC harness. I used a '91-'93 ECU with EGR delete. All made sense when I was looking at this back on '08-'09..... (Been a while....) Harness is great and the service was great during the build as well.
After getting all the pieces, I ended up being able to buy a crate '96 DOHC so ended up selling off the '95 DOHC. Again, this was all eons ago in '08-'10.
I am now at the point of installing the '96 DOHC with a Getrag 5 spd into my project car. I laid out the wiring harness this past weekend found that very little was the same for plugs etc. That is when I started digging and remembered the info I put above.... (Again, really has been a while...)
Where I am today and a long way around to asking my questions.
- '96 DOHC full engine with all sensors bought and installed for a '96 install
- the difficult 24x crank sensor is already on the engine as well.... (apparently that is an issue with getting OBDII setup on most swaps?)
- '91-'93 ECU and engine harness
- 5 spd Getrag transmission
- I was reading that it was only possible to do an auto swap with OBDII?
- Updated fuel pump in tank and ready to be put back into the car.
- Battery relocate up front with 1 gauge cables coming back into engine bay ready to power up system
All sitting on the cradle ready to go.
Questions:
1. Does it make sense to get a new harness built that allows for ODBII as now it is much more refined than back when these were first talked about?
a. In reading old posts, the '96 has SFI not batch injector operation but only up to 3000 rpm when it switches to batch
b. I have two O2 sensors and several other additional sensors that would not be needed with a '91-'93 ECU
2. If I am to get a new harness, who makes one and what else do I need to do to the car/engine to install the OBDII vs. OBDI?
3. Are there significant issues that crop up when doing an ODBII install compared to the OBDI?
4. Just to muddy the waters a bit more, would OBD 1.5 be a better option for me since I already have the sensors that would connect to that setup and still give me SFI???
Realistically, staying with the '91-'93 harness would be a bit cheaper but I do want to do this the right way all along as this project car has been a work of love for a while now....
Hopefully someone can help me out here. I am agnostic on which way to go as I have to spend some money to either get a new harness or go return and purchase my '91-'93 senors that will work with the harness.
Thanks
Don
A pic of the car the engine and trans are going into a pic of the engine trans setup.
[img]https://i.imgur.com/Iynl7On.jpg[/img]
[img]https://i.imgur.com/y5k19Kz.jpg[/img]
[img]https://i.imgur.com/3FBpjeS.jpg[/img]