Engine wire harness question

[haaken675]

Hey everyone,

My megasquirt unit just came in so I decided to take another look at my harness and double check all of my traced wires label everything before i start the install process. Something I hadn't really thought about until jus now was the relays on the engine harness. They appear to be either unnecessary (in the case of the secondary air pump relay) and potentially duplicates such as unloader relay, fuel pump relay, and main relay.

Someone please correct me if I am wrong, but the unloader relay, fuel pump relay, and main relay are all in the engine bay fuse box. Can I remove these without worry from the main engine harness as they appear to be duplicates? I can't think of any reason why not, but I wanted to make sure.

Thanks

[haaken675]

so I may have bene wrong, looks like the fuel pump relay and main relay are not in the fuse box, just the fuses for them. That being said, can I remove what appears to be an additional unloader relay from my m52 wire harenss?

[Sh3rpak!ng]

I'd study the wire diagrams and trace it all and figure it out from there. I don't think anyone usually removes any of those items when doing these swaps with the oe ecu/harness.

Personally I reviewed the diagrams for both the e30 and the s52 and based on what accessories I knew I would be using, I cut and pulled out the rest of it (like the SAP relay and wiring).

IIRC the three relays with the 24v harness are main, fuel pump and O2 heater. Not sure what you can and cant remove when youre running megasquirt though

[haaken675]

I have been going through an m52 wire diagram over and over, and will definitely go over again before I actual wire up the megasquirt. Part of the reason I have more questions then the normal I suppose is my car being an '87 I have an odd c101 setup and some different wiring then all the diagrams I have seen so far.

It looks like by the time I am done I am going to have a nearly one-off harness...

[haaken675]

The diagram from the Bentley manual show an unloader relay as well as the secondary air pump relay on the diagrams. I am nearly 100% confident I can eliminate the SAP relay. it's the additional unloader relay i'm not sure about. My '87 for sure has an unloader relay in the fuse box as it is, and from my understanding the '87 and potentially earlier round c101's tied in the unloader into a different circuit then the newer cars.