DigitalSynthesis

Ok, I'm sitting here scratching my head looking at wiring diagrams and the two harnesses (one is A-Spec NA Engine harness, the other is J-Spec Turbo Engine harness) and the two trannies in front of me.

The A-Spec NA transmission has a back-up light + 5th switch with 4 connectors on it. The J-Spec Turbo tranny has only 2 connectors on the same switch.

The harnesses differ as follows:

1. The A-spec harness has the black/blue wire for the "Over Top Switch" in place. The J-spec harness is both missing this connector on the harness and does not have the pin for this in the FE-03 connector which goes to the Front harness and subsequently to the ECU.

2. The A-spec harness also has the black-red line for the sub-zero sensor which the j-spec is also missing, along with the corresponding pin in the FE-03 connector as well.

What is this "Over Top Switch", where is it in my car (I can't find it mentioned in the FSM section J2 on the TII tranny), and is it important? I would assume not since I'm using the TII ECU and tranny and harness, but the differences made me very curious.

Obviously the lack of the stupid-*** subzero start system does not make me in any way upset.

Also, the back-up light and 5th switch unit only having 2 connectors makes me a little worried. Do Japanese cars not have reverse (backing up) lights?

HAILERS

Over the top sw is the same thing as the fifth gear sw. It's located on the left side of the transmisision.

Neutral switch is on the right side of the transmission.

I put a turbo engine/transimision in a non turbo. Those wires drove me buggy because they were not

the same as on a turbo verses non turbo transmission.


The only reasonable way to deal with this is to put a meter lead on the ECU plug/pin for the item your looking for and then go to under the car to the mess of wires and with the other lead see which wire has continuity to that pin on the ECU. Do it for each circuit you are trying to find

Yeah, OVER THE TOP is the same as FIFTH GEAR SWITCH.

Heck, on my conversion I had to cut and add additional wire length to some wires so they would connect together. Not much of an answer since I can't tell you just which wires to connect to each other. Sorry 'bout that.

DigitalSynthesis

Hm... ok that's fascinating. The FSM wiring diagram itself actually refers to separate "Over Top" and 5th gear/reverse light switches. Having scanned the wiring diagram thoroughly what you say makes total sense. But the odd thing about it is this: the TII tranny has 2 LESS connectors than my NA tranny. E.g. that 5th gear switch should have 4 connectors, right? 2 for 5th gear, 2 for reverse. BUT, its only got 2. And it looks like they are for the reverse light. There are no wires in the harness for the 5th gear switch, and there are no pins on the switch that connect to any 5th gear wire as described by the wiring diagram.

Since I have the factory wiring diagram, I know exactly where each wire goes, and I have even pulled the entire harness (to rewire the battery cables and grounds) and traced each wire to ensure that they match the factory diagram. They do. Its the "Over Top" (= 5th gear) wire that does not exist, neither on the harness nor on the tranny. The switch is there, just with only 2 contact points, not 4. Go figure.

Does anybody know what the ECU does with the 5th gear signal anyway? I know for an absolute fact that the Neutral switch on my old NA tranny was completely busted for the entire time I owned the car (wires were cut off entirely) and it didn't seem to make a whit of a difference.

DigitalSynthesis

Does anybody have any ideas on this?

silverrotor

iTrader: (1)

I'd like to know too. Did you have any problems with the back up lights? Fortunately for me, I figured It out.

AE_Racer

iTrader: (1)

doesnt the switch make you get better gas mileage in 5th gear? i remember reading that, but its prob wrong

silverrotor

iTrader: (1)

5th Gear Is the gas saver gear. Correct me If I'm wrong, put when going standalone this function with the 5th gear Is Irrevant, (electrically speaking)?

HAILERS

I'm looking at a 91FSM, page J2-45 (Transmission Section), and it shows the transmission. It has four connectors coming out of the switch on the left hand side. Two look like bullet connectors, the other two look like regular plastic connectors.

It also shows the switch on the right hand side of the transmission with one plastic connector.

The words say *connecto the neutral switch, and back-up light and 5th switch connectors.

One thing the OVER THE TOP SWITCH does......is put a ground on the split air solenoid to direct airpump airflow to the catalytic converter when in 5th gear. Other things that it effects are the switching solenoid and the relief solenoid, bac, and believe it or not, the Lead and Trailing timing. SEE THE FSM, F1(CONTROL SYSTEM) for verification.

Same section: The neutral switch effects the fuel injection amount, fuel pump resistsor relay, A/C relay, split air solenoid, switching solenoid, relief solenoid, aws, fpr, bac, trail and lead timing.

One thing the neutral switch does is effect the cold air start system.

HAILERS

From what I see in your post.........I think you've got the wrong switch in the transmission if it only has two wires instead of four. Maybe you have a automatic transmission switch?? Or...??????

silverrotor

iTrader: (1)

I could confirm that DigitalSynthesis Is correct. I have the same Issue with the 4 wires > two wires.

HAILERS

What can I say????? The FSM for the 91 shows four wires in the picture on that page referenced and my 87/86 cars have four wires coming out of the left hand side.

HAILERS

The picture:

silverrotor

iTrader: (1)

I can't comment on specifics on the wire up just yet. My car Is 20 minutes away. Hopefully, DigitalSynthesis can chime In real soon seeing how he has both Trannies accessible.

HAILERS

IF there are but two wires coming out of the switch.....see what those two are doing for a living. Put a meter on ohms and put the meter leads on both wires and then select fifth gear and then reverse. Which position showed a result?

DigitalSynthesis

The harness and tranny only have two wires. From the color alone (according to the factory diagram) its reverse. All the shifter bushings and stuff are out of the tranny right now so I can't easily check, but since the switch itself only has two plugs, and the color (and pin position in the Engine harness) indicates conclusively that its the reverse wires that remain in existance, i would assume that is the actual case.

DigitalSynthesis

The switch in the tranny was completely wired and the vehicle was (to my knowledge) run like that for at least a long time, if not its entire life. There are NOT 4 wires, on the switch, nor on the harness. There are only 2. They are the bullet-plug ones. The spade-type plastic connectors are the ones that are not there. I have the 4-unit switch on my other (NA) tranny, but it is so damaged that I cannot reuse it or the harness it came on. The switch appears to pull double duty, if I push the activator in halfway it clicks like there is a stop there. If i push it in all the way there is another click. I would assume, since 5th and reverse are on the same selector fork, that its just detecting which position that fork is in and shorting the appropriate leads of the switch. Thus, to make a reverse-only version for the emissions-challenged Japanese would not be improbable. Do the Japanese not run converters at all? Or do they just not care about 5th gear?

AE_Racer

iTrader: (1)

japanese do not have emissions...but I do think they have cats

HAILERS

Ok. I didn't really pay attention to the JDM part. Use it as a reverse switch then. One wire should go to the backup lights then and the other is most likely for a ocnstant 12v source from the ignition with a fuse inbetween. Maybe that's the way it works. Maybe not.

HAILERS

NZCONVERTIBLE has a JDM car.

Sideways7

iTrader: (7)

From looking at these posts, it sounds like two of the wires on the A-spec tranny are somehow related to emmisions. I don't think J-spec cars have a lot of the emmisions stuff the US cars have, so would the two missing connectors be related to stuff that isn' t on the j-spec cars? If the cars dont have what the wires connect to, there wouldnt be a need to have the connectors on the tranny. Just do what HAILERS said and figure out which wire you need.
Im just throwing this out as a possiblity that someone needs to verify, since I don't have much experience with J-spec cars.

HAILERS

IF I remember right, in a recent post someone mentioned the ACV on a Jap car has no split air or Port Air solenoid, so.......maybe they just have a reverse switch only. Guessing.

DigitalSynthesis

The ACV I have seems to have both, but I may be remembering it incorrectly. I will have to check again for you.

Edit: my bad. ACV... duh.