Performing an Auto KA to Auto SR swap, have a few questions.

[DriftingisLame]

Hi guys, long time nissan guy here, first time SR swap though.

First off I'm doing the swap for a friend of mine, its a 91 coupe, had a KA auto in it, and I just installed an SR automatic. I have a few questions for you that I havent been able to find with a search.

1. Does anyone have a write up done with an Automatic SR swap? What am I supposed to do with the transmission wiring, it seems like the SR autos and KA autos are the same, and I believe there is a controller for the trans, seems to me I would use the KA controller for this trans as well.

2. What #'s should be on my MAF? I have located the maf plug, but the plug does not match up with the MAF, I believe I have the wrong MAF. The engine was a motorset, and this maf was just zip tied to the side of it.

I'm sure I'll have many more questions but those seem to be the only one's I'm really concerned about that I can remember. Overall the harness's seem much different to me than those I've found in the wiring write ups online, but I still think I can figure it out without too much stress. Any comments, or constructive criticism's are appreciated.

Let me know if you guys need some pictures, and I'll go snap some.

Thanks
-Max

[OM3GA]

How will you be able to drift with auto?

The controller may be the same, i believe the wiring is the same or pretty close if i am not mistaken. I would definitely look at the connectors on both transmissions as well. Look at the plug for the TCU as well on both the ka upper and the sr upper harness.

This swap is NOT that common at all, it has always been tough to find info on that topic but do not let that discourage you.

[DriftingisLame]

Lol, I'm sure he'll find a way to drift. He has more experience driving an auto than most of us.

I'll go over both harnesses, I believe the wiring from the SR transmission has been cut unfortunately. I should have checked this stuff before I put the motor in. I think the SR and KA manuals are close to the same and use the same sensors, so hopefully the automatic wiring from the KA will operate the SR trans.

Any help on the MAF? What numbers am I looking for on the SR maf, I'll go check what the maf I have says and post them, or take a picture.

-Max

[surfpac]

I did this swap 10 years ago...

1. The automatic control unit on the KA is similar, if not the same, as the SR unit, so wire in the extra wires from that SR wiring harness into the KA auto transmission unit. This unit sits just above the stock ECU location in passenger kick panel. Use the wiring diagram from the FSM to help you out. I think it was only 4 wires I connected, or maybe 5. Also you need to use an SR ecu for an automatic, don't use a manual SR ECU because the shift points will be all screwed up and the motor will rev high before shifting.

2. The MAFS from the 91 KA DOHC will not work on that SR wiring. You need a MAFS from a SOHC KA motor 89-90. The connector should plug right into the KA SOHC MAFS if I remember correctly.

I drove the SR automatic for 8 years with no issues at all before going manual. I used Mobil synthetic transmission fluid in conjunction with a transmission cooler. I also used a digital pressure switch to open a solenoid circuit (the resistor that sits on the drivers side strut area) to enable quick/harder shifting when boosting above 8 psi.