DIY: In depth M52/S52 OBD2 swap

[craiggroves91]

Added some info about the intake boot, IAT, and ECU mount.

And the car is running much better now with the MAF in

[Leo_328i]

Absolutely awesome write-up!!!

I'm doing an OBD2 swap very shortly into my 90 318iS (yes, we got MY1990 in Australia) and am trying to find a way to bypass or trick the EWS.

Unfortunately no one in Australia seems to be able to do this and I really don't want to have to send my Euro ECU all the way to the USA to get deleted when no one can even confirm that they can work on a non-US ECU.

Has anyone figured out a really simple easy way to do this?

[craiggroves91]

Absolutely awesome write-up!!!

I'm doing an OBD2 swap very shortly into my 90 318iS (yes, we got MY1990 in Australia) and am trying to find a way to bypass or trick the EWS.

Unfortunately no one in Australia seems to be able to do this and I really don't want to have to send my Euro ECU all the way to the USA to get deleted when no one can even confirm that they can work on a non-US ECU.

Has anyone figured out a really simple easy way to do this?

I'm not familiar with the euro swaps, but I'd imagine if you get all the EWS components from the car you got the engine from (if still possible) you could make it work!
I'm sure you could also find a cheap way to ship your ECU over here! International USPS flat rate?

[Leo_328i]

I've already go the engine, harness and ECU but it doesn't have EWS!

To be honest, it would be just better to delete the EWS and not have to incur the $280 or so expense of getting stuff deleted.

I am being a real tight arse about this but I am Asian!

[luckysnafu]

I've already go the engine, harness and ECU but it doesn't have EWS!

Do you have the key that matches the ECU?

[Leo_328i]

Unfortunately not.

[328ijunkie]

Also: Best way to do OBD2 IAT sensor is thread it into the OBD1 sensor port ;)

[Mr.SWISS]

I realize you deleted the throttle circuit so you needed the sensor to plug that port, but it screws directly into the port to it's left with no modifications,that's just a plug for the extra hole on the OBD1 heads used on early OBD2 engines. Not all OBD2 motors have that, but what I did on my 99 S52 was get an OBD1 head and have it machined to S52 spec and gain the extra sender hole.

[giantkeeper]

Also: Best way to do OBD2 IAT sensor is thread it into the OBD1 sensor port ;)

This is what we did on tttoon's car. Easy to do and worth the extra 10 minutes!

[VinniE30]

Intake boot and IAT sensor:
You'll want the long OBD1 intake boot with 2 holes in the bottom. One for the ICV hose and the other to either plug or mount your OBD2 IAT sensor in.
I chose to mount my IAT sensor in the boot, since this is more ideal than rethreading it to mount it in the original OBD1 IAT spot on the intake manifold.
To mount the IAT sensor in the hole you'll want to shave off some of the plastic to make it more round like pictured below.
Before:

After:


OBD1 intake boot part number: 13541738757

If you say the original spot for the IAT sensor is on the intake manifold, and your putting it in a hole in the intake boot, what use to be in that hole in the intake boot originally?

[craiggroves91]

Also: Best way to do OBD2 IAT sensor is thread it into the OBD1 sensor port ;)

I'm not sure if this is really the BEST way is it? What makes it better than the boot?

I realize you deleted the throttle circuit so you needed the sensor to plug that port, but it screws directly into the port to it's left with no modifications,that's just a plug for the extra hole on the OBD1 heads used on early OBD2 engines. Not all OBD2 motors have that, but what I did on my 99 S52 was get an OBD1 head and have it machined to S52 spec and gain the extra sender hole.

Wait, so you're saying on my s52 head that plug has the same threads as the unmodified e30 coolant temp sensor?

interesting

If you say the original spot for the IAT sensor is on the intake manifold, and your putting it in a hole in the intake boot, what use to be in that hole in the intake boot originally?

Well since its a boot from an OBD1 car its different and that hole is not needed on OBD2 car.

I'm not sure what that hole is used for on OBD1 cars, I'd have to look at one.

[craiggroves91]

Added electric fan and reverse lights information

[PeabnutBubber]

On my original post I already thanked you but I figured I would do it here as well. HUGE thanks for this, man. As soon as I'm ready to start this project this is going to be a massive help. It seems that pretty much everything is in here. All I need now is some parts and a little bit of time. Thanks again! I'll update the other thread as I do it in case anyone's interested. Stop by Tallahassee for a beer one day!

[maniacmatt]

This is a great write up! Awesome info!

What do all you OBDII guys do for the diagnostic port?

[Slovik]

I bought something similar to this, works fine and real cheap.

http://www.ebay.com/itm/BMW-20pin-Connector-to-OBD2-OBDII-16-Pin-Connector-Converter-/140892142780?pt=Motors_Automotive_Tools&hash=item20cdd37cbc&vxp=mtr