The Official OBD1 vs OBD2 argument thread.

[328ijunkie]

None really other than the extra wiring and annoyance of having to get the components in there. I plan to one day do a swap with EWS (to be honest ive always flashed it out) just to have the cool security system and put the transponder in the stock E30 key and everything...

[übersteuern]

Just to backtrack a bit...ok a lot...

I thought if you had all the parts (ECU, ignition, and harness from the same car you didnt have to flash your ECU?

You are correct, no flashing necessary with all the EWS components

What are the downsides of running EWS instead of doing EWS delete on an M52? (assuming the engine will be installed in stock configuation)

Thanks

[Wanganstyle]

But to get your car to pass the BAR in CA it is going to be easier to go OBD 1. I'm not saying OBD 2 can't be done for the CA BAR. I just haven't seen it done.

incorrect.

CA bar requires OBD2 to be retained with the M52 or S52 engine. CA BAR info here:

COMPUTER CONTROLS
If a computer–controlled engine is installed in a non–computerized vehicle, the "CHECK ENGINE" light, the Original Equipment Manufacturer (OEM) diagnostic link, and all sensors, switches, and wiring harnesses needed to make the system fully functional must also be installed.


EMISSION CONTROL CONFIGURATION
Mixing and matching emission control system components could cause problems and is generally not allowed. Engine and emission control systems must be in an engine–chassis configuration certified by the California Air Resources Board (ARB) or U.S. Environmental Protection Agency (EPA). The engine must meet or exceed the requirements for the year and class of vehicle in which it is installed.

ORIGINAL EQUIPMENT
The installed engine and host chassis must retain all of their original emission control equipment. Diesel–to–gasoline conversions must have all gasoline engine and chassis emission control systems installed (such as fillpipe restrictor, catalytic converter and evaporative emission system).


if you are converting a S52 to obd1 and going to the bar, you are not going by BAR rules.

The BAR ref will be able to look at the plugged up or unplugged CPS sensor of the S52 in the back of the engine block and ask why the OBD2 system is not there.

CA bar is not stupid, they know every single Nissan engine swap (so does the CHP). They are trained on it. I'm sure you can lie and get away, but why?

[surebimmer]

I'm no expert, but I can't think of one. I haven't seen any definitive proof that one makes more power vs. the other (assuming manifolds, displacements, etc. are the same).

For me, simplicity wins the day and OBDI is simpler (as well as easier to chip). OBDII was designed for tighter controls on emissions, not to make more power. In some vehicles, it can be a nightmare to keep running as the car ages and fails emissions for check engine lights that have no realized impact on how the vehicle performs.

It seems like people generally go OBDII b/c when they pull the engine, they can pull everything they need to convert, so at that point, its cheaper than tracking down the OBDI items.

This was my main point. If you buy a OBD 2 S52 with everything then go ahead and run it OBD 2. Does the OBD2 computer make more power vs s52 obd 1? I would like to see some info on this. I like that the OBD 2 runs 2 O2 sensors one for each bank. But to get your car to pass the BAR in CA it is going to be easier to go OBD 1. I'm not saying OBD 2 can't be done for the CA BAR. I just haven't seen it done.

[Mr.SWISS]

OBD2 here, wouldn't have it any other way.

[nrubenstein]

I understand when the swaps were being done a couple of years ago OBD1 was the way to go as no one had the OBD2 flashing figured out yet.

Coming from the Audi world, I do know that being able to flash and tune an ECU via the OBD2 port opens up a new realm of possibilities vs. having to flash a chip. Now that tuners are making OBD2 flashes it seems to be the way to go, but I am just curious to know if 'upgrading' to OBD2 is worth anything.

As of right now, the advantage to OBDII is diagnostics.

The disadvantage is that you have fewer tuning options (but excellent tuning IS available).

Basically, if you're chasing your tail with electrical issues, then it might be worth it to convert back to OBDII. Otherwise, stick with what you've got that is working.

[Pl3wA]

Im going OBD1 s52 WOOOO!!!

[MC Hammered]

I understand when the swaps were being done a couple of years ago OBD1 was the way to go as no one had the OBD2 flashing figured out yet.

Coming from the Audi world, I do know that being able to flash and tune an ECU via the OBD2 port opens up a new realm of possibilities vs. having to flash a chip. Now that tuners are making OBD2 flashes it seems to be the way to go, but I am just curious to know if 'upgrading' to OBD2 is worth anything.

[uberm3]

If a car is already running a s52 OBD1 setup is there any reason or benefit to change it to OBD2?

I'm no expert, but I can't think of one. I haven't seen any definitive proof that one makes more power vs. the other (assuming manifolds, displacements, etc. are the same).

For me, simplicity wins the day and OBDI is simpler (as well as easier to chip). OBDII was designed for tighter controls on emissions, not to make more power. In some vehicles, it can be a nightmare to keep running as the car ages and fails emissions for check engine lights that have no realized impact on how the vehicle performs.

It seems like people generally go OBDII b/c when they pull the engine, they can pull everything they need to convert, so at that point, its cheaper than tracking down the OBDI items.

[nando]

EDIT 2: So is anything else needed on the X6031 besides Pin 1 (CEL) and Pin 3 (VSS)?

I don't think so, unless you want the emissions stuff.

[mammoth_e30]

This is really good stuff, guys, please keep it up.

+1

Thank you very much nando & 3281junkie for correcting me and the misinformation i got from bf.c

i'm up for some collaboration Gooch. I wanted to get it wired and running myself with my own adapter (OCD) and then send my harness to 328ijunkie to get it pinned all nice and pretty. This is mainly because I want to run most of the OBD2 emissions related equip and not all of it goes through the X20, the carbon canister and fuel tank pressure valve go through X6031.

[Gooch]

This is really good stuff, guys, please keep it up.

Mammoth, I think we're going to need to collaborate a little bit...I need to spend some more time in the OBDII ETM, though.

EDIT: I think I started the confusion regarding VSS/RPM. Meant VSS but said RPM before, gonna go ahead and edit that in my other post.

EDIT 2: So is anything else needed on the X6031 besides Pin 1 (CEL) and Pin 3 (VSS)?

[nando]

pin 20 on C101 (red/yellow) should be ABS and needs power from the harness or a fuse from what I have read.

Pin 14 x20 in OBD1 should be the RPM accoring to the 1995 ETM 6211.0-03.

In OBD2 it looks like this signal goes directly to the instrument cluster. 1998 ETM 6211.0-03 & 6211.0-04.

If I'm incorrect please school me, I'm new at reading these and could be missing something.

pin 20 already has power from the harness side, or as 328ijunkie said, sometimes it's a ground (cars with an ABS relay). you don't add power to it, unless you want a massive short and/or electrical fire. you do sometimes jump it to pin 6 to provide power to the ABS on later cars. But you never add 12v to pin 20. It's meant to provide power to the OBD port. it's also fused already.

pin 14 is always VSS, never RPM. On OBD2 it moved to X6031 pin 3.

[328ijunkie]

pin 20 on C101 (red/yellow) should be ABS and needs power from the harness or a fuse from what I have read.

and this is how you burn your car to the ground. If you supply it with +12 and its supposed to be a simple ground. Then fire will happen..

Pin 14 x20 in OBD1 should be the RPM accoring to the 1995 ETM 6211.0-03.

In OBD2 it looks like this signal goes directly to the instrument cluster. 1998 ETM 6211.0-03 & 6211.0-04.

If I'm incorrect please school me, I'm new at reading these and could be missing something.

On OBD1 Pin 14 on the X20 is VSS not RPM.

[mammoth_e30]

Pin 20 on the C101 is EITHER a ground or a needed Hot wire. If you mix it up youll burn the car to the ground as nothing there is fused.
Ive never seen a OBD2 harness with a pin 14.

Pin 14 on the C101 is typically VSS.

pin 20 on C101 (red/yellow) should be ABS and Edit: removed

Pin 14 x20 in OBD1 should be the edit: VSS according to the 1995 ETM 6211.0-03.

In OBD2 it looks like this signal goes directly to the instrument cluster. 1998 ETM 6211.0-03 & 6211.0-04.

If I'm incorrect please school me, I'm new at reading these and could be missing something.