OBD2 S50 up and running!

[ZekeTheSneak]

The red lug is 12v from the battery. Passenger side bulkhead on firewall. Same place the fuse box connects and the starter wire connects. What car is this going into? Solid red wires usually are 12v from the battery. If you trace those wires they supply 12v to the main relay. Red and white wires are key on 12v. They are supplied from the main relay. Brown is always ground. Black is almost always 12v

[jjc034]

The orange relay. Trace all the wires. The big red wire with the lug on it goes to the battery. You need the lug connected for the other relays to work. This is bthe main power for the harness. You can cut the orange relay off and remove all the wires associated with the relay. One is red 12v from battery lug. One is common ground. One goes to the sap connector and one wire goes to the dme. I would physically remove all the wire and you will see it's pretty straight forward. I think the burned harness happens when you swap the green and red relays.

Thank you @ZekeTheSneak. That red terminal is supposedly used to power the E36 fuse box. The E30 has a separate power wire for the fuse box, so this is where I'm struggling.

E36 wiring harness has 12v power and ground on passenger side, then this additional 12v power lead on drivers side attached to Fuses. I'm just gonna take a closer look tonight

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[ZekeTheSneak]

No lol the relay

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The orange relay. Trace all the wires. The big red wire with the lug on it goes to the battery. You need the lug connected for the other relays to work. This is bthe main power for the harness. You can cut the orange relay off and remove all the wires associated with the relay. One is red 12v from battery lug. One is common ground. One goes to the sap connector and one wire goes to the dme. I would physically remove all the wire and you will see it's pretty straight forward. I think the burned harness happens when you swap the green and red relays.

[S.Low]

Haha thank you.

Did you do this on e30 or e36? If e36 I understand how you left the power in factory location. If e30, where'd you mount that power wire?

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E36 :p LOL

[jjc034]

OH OH!! All that crap still plugged in the the same way from factory. I literally modified nothing on the harness. Last thing i needed at the time was more headaches lol

Haha thank you.

Did you do this on e30 or e36? If e36 I understand how you left the power in factory location. If e30, where'd you mount that power wire?

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[S.Low]

No lol the relay

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OH OH!! All that crap still plugged in the the same way from factory. I literally modified nothing on the harness. Last thing i needed at the time was more headaches lol

[jjc034]

The plug that goes into the SAP? Yeah just taped it off, no problems so far knock on wood. It's not a show car or anything, I just tucked it away nicely.

No lol the relay

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[S.Low]

So you simply unplugged that relay and left the 12v power going from driver to passenger side off?

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The plug that goes into the SAP? Yeah just taped it off, no problems so far knock on wood. It's not a show car or anything, I just tucked it away nicely.

[S.Low]

I'm saying it's the tune. Nothing else will fix it.

It's been so long I don't even remember what did the fix anymore, let's just say that the Tune fixed it :D still going strong

OBDII m50b30 on my 96 328I tuned by RK-Tuens Jordan

[jjc034]

Yeah so I din't do anything to my harness at all, just took everything out. Sorry cannot be much help lol

So you simply unplugged that relay and left the 12v power going from driver to passenger side off?

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[S.Low]

@S.Low how did you remove your SAP system from the OBD2 harness. Passenger side is easy because it's only one relay, the SAP connecter, and ground strap.

Driver side is confusing me where it's the fuel pump and ECM relays, then the SAP relay with a power wire leading to a 12v terminal wire extending from the passenger to driver side.

How do I delete without burning the ground wire?

Thanks,
John

Yeah so I din't do anything to my harness at all, just took everything out. Sorry cannot be much help lol

[jjc034]

The sap is a four wire relay correct? When I deleted mine I just used a multi meter and traced all the wires. Power and ground for sap. 12v from battery. Common ground. And one wire to the dme. Which I just cut back and capped off. I believe what Fry's them is when you put a green relay in place of the purple sap relay.



Do you own a multi meter? Test for continuity on all the wires and trace everything. On my harness the sap relay was completely independent of the other 3 relays meaning they we're not connected in anyway except maybe battery 12v. I can look tonight at my notes but you need to triple check everything with a meter regardless.

Yeah, i was going to go at it with a multimeter tonight to test for continuity. So when you say you cut the wires, you mean the ones on the orange SAP relay? Nothing from the passenger side?

Edit: I'm an idiot, I think my harness already has that SAP relay disconnected on the driver side. Pic 3


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[ZekeTheSneak]

The sap is a four wire relay correct? When I deleted mine I just used a multi meter and traced all the wires. Power and ground for sap. 12v from battery. Common ground. And one wire to the dme. Which I just cut back and capped off. I believe what Fry's them is when you put a green relay in place of the purple sap relay.

Do you own a multi meter? Test for continuity on all the wires and trace everything. On my harness the sap relay was completely independent of the other 3 relays meaning they we're not connected in anyway except maybe battery 12v. I can look tonight at my notes but you need to triple check everything with a meter regardless.

[jjc034]

Got that low oil pressure issue fixed up. But yet another issue.

Misfiring under load and sometimes just trying to open the throttle.

I'm assuming Harness and coil packs are good since they were on the car and were fine before I pulled the engine 2 months ago. I'm pulling my hairs once again. Plugs look fine also.

I am using the obd1 throttle body and no 2ndary air pump. That's all I've changed from stock.

As far as engine timing. I triple checked it and everything ligned up after rotating the assembly.

Anyone had these issues after doing this conversion? Any tips on where I should be looking at?

Any help greatly appreciated

@S.Low how did you remove your SAP system from the OBD2 harness. Passenger side is easy because it's only one relay, the SAP connecter, and ground strap.

Driver side is confusing me where it's the fuel pump and ECM relays, then the SAP relay with a power wire leading to a 12v terminal wire extending from the passenger to driver side.

How do I delete without burning the ground wire?

Thanks,
John

[328ijunkie]

I'm saying it's the tune. Nothing else will fix it.