Couple OBD-II wiring questions (Not C101/x20 adapter)

[Gooch]

Finally finishing up the OBD-II S52 swap and I'm down to the last few orders of business, one of which is the wiring and my two questions are as follows:

1. What is this relay? I can't find it on realoem, Bentley or the ETM. Maybe I'm not looking hard enough, but I can't find it and don't remember where it was located in the e36 (engine bay or glove compartment??). The only things I can think of are the secondary air pump or something with EWS, in which case I'm not going to to need it...I had TRM flash it out among other things. (1a. I also was wondering what that other plug was for, but in my journey from the garage to the computer I am pretty sure it's the secondary air pump connector, just have to verify when I go back downstairs.) EDIT: Confirmed.



2. Next, it is my understanding that the wire indicated in blue is not necessary on the e30 and can be removed. Can I splice the two wires indicated in orange together to get power for the relay once I remove the larger power wire from the harness? Is that the easiest way to go about getting power for that relay?



Thanks in advance.

[mammoth_e30]

Finally finishing up the OBD-II S52 swap and I'm down to the last few orders of business, one of which is the wiring and my two questions are as follows:

1. What is this relay? I can't find it on realoem, Bentley or the ETM. Maybe I'm not looking hard enough, but I can't find it and don't remember where it was located in the e36 (engine bay or glove compartment??). The only things I can think of are the secondary air pump or something with EWS, in which case I'm not going to to need it...I had TRM flash it out among other things. (1a. I also was wondering what that other plug was for, but in my journey from the garage to the computer I am pretty sure it's the secondary air pump connector, just have to verify when I go back downstairs.) EDIT: Confirmed.

The Secondary Air pump relay is in your second picture with the ECM and the fuel pump relay and yes that is it's connection pictured as you obviously confirmed. I think that relay may be what is called the unloader relay and i wouldn't remove it.

2. Next, it is my understanding that the wire indicated in blue is not necessary on the e30 and can be removed. Can I splice the two wires indicated in orange together to get power for the relay once I remove the larger power wire from the harness? Is that the easiest way to go about getting power for that relay?



Thanks in advance

The blue arrow is to the connection that fed power to the e36 power distribution box (fuse box).

The left relay is the ECM, the middle is the fuel pump and the right should be the secondary air pump relay.

I am basing this information off of the harness of a '98 M3, personally I wouldn't fuck with it.

[328ijunkie]

If you dont remove the SAP relay properly youll short it and the ground wire will fry all the way through the harness. Seen this happen a few times. (not to me personally). Never dug deep enough to figure out why it happens.

[plain325]

If you dont remove the SAP relay properly youll short it and the ground wire will fry all the way through the harness. Seen this happen a few times. (not to me personally). Never dug deep enough to figure out why it happens.

So i cant just pull the SAP relay and cut the wires to it? I have already been running with no SAP installed, i just left the plug there. I want to trim up my harness, so i want to eliminate what is not needed.

[choleaoum]

bump, curious as well.

[plain325]

So i cant just pull the SAP relay and cut the wires to it? I have already been running with no SAP installed, i just left the plug there. I want to trim up my harness, so i want to eliminate what is not needed.

Anyone? I want to finish up my harness this weekend, and i would like to remove what i dont need.

Can i just cut the wires to the SAP relay? Or does this cause a problem?

[Gooch]

Anyone? I want to finish up my harness this weekend, and i would like to remove what i dont need.

Can i just cut the wires to the SAP relay? Or does this cause a problem?

I completely removed the SAP, relay, and all associated wiring with no ill-issues. I was not willing to take the chance of burning up the ground (as described by Dave) by just cutting the wires. Good luck with the rest of your swap!

[328ijunkie]

Its not bad to completely remove the relay/plug. Youre just left basically if you clean up everything with the 1 spare wire that triggers the relay from the ECU. :D

[plain325]

Its not bad to completely remove the relay/plug. Youre just left basically if you clean up everything with the 1 spare wire that triggers the relay from the ECU. :D

Thats kind of figured, i could remove it all. I just was not sure what situation caused a ground to burn up.

For all of the things i have not been using, i am just cutting the wires about a ft from the ecu plug and capping them with a piece of heat shrink, has anyone done anything else?

[E30 325i]

Reviving old thread.

I eliminated SAP in my obd2 m52 swap along with the TRM tune that ditches it as well. That said brown wire burns instantly when you put the wrong 5 pin relay in the SAP socket. Ask me how i know! It burns it to a grouping of several larger guage grounds about 1 foot before DME. With that said, i always wondered if i could ditch the relay, socket, and all wires associated with it. It would clean up my wiring nice.

My swap is not quite done. I'll post my findings.

[Gooch]

That's what I did; been running great with no issues.

[robgoesvroom]

Are these extra plugs an issue on Dave's plug n play harness or are they already trimmed and snipped? I hear the harnesses are even labeled for your convenience to eliminate this guessing game!

[jjc034]

Reviving this. Would someone be able to show me the final result?

Two questions:
1) Did you remove the SAP fuse or leave it be even though SAP is deleted?

2) What did you do with the 12v terminal? Mount it to the starter or connect somewhere else?

Thanks,
John

Sent from my SM-G930V using Tapatalk

[jjc034]

I completely removed the SAP, relay, and all associated wiring with no ill-issues. I was not willing to take the chance of burning up the ground (as described by Dave) by just cutting the wires. Good luck with the rest of your swap!

@Gooch would you be able to show a pic of what your driver side string of relays looks like? I'm a visual person and want to make sure I don't mess this up

[Balleristic31]

Reviving this. Would someone be able to show me the final result?

Two questions:
1) Did you remove the SAP fuse or leave it be even though SAP is deleted?

2) What did you do with the 12v terminal? Mount it to the starter or connect somewhere else?

Thanks,
John

Sent from my SM-G930V using Tapatalk

Bumping this. I'm interested in the answer to question #2 as well.