[Majortob]

Hi all,

Having some strange issues with the reverse switch in our build.
Engine is a g13bb with a sj50(?) gearbox. Microsquirt and Custom writing loom throughout.
The issue we are having is the reverse switch comes on it both reverse AND fifth. Anyone had this before?
We have taken the switch out and inspected it and it works fine. It’s activating in the wrong gear!
Any insights?

[bumstein]

Can’t think of anything that would cause this off the top of my head but I’d be looking at what the detent ball is doing.

Im going to assume that the reverse lights are OFF when the box is in neutral?

If you’re looking at the gearbox from the top, the very left hand shift rod shifts 5th and reverse gears. On that side of the box there are two switches. The front switch activates when in reverse and the rear activates when in 5th.

Pop the switches out, make sure the detent balls are in place and the right size (there are two different sizes) and the shift rod is on good nick.

[Gwagensteve]

I’m not sure that’s the case for the sj50 box Bumstein. I thought only the Sj70 box has switches for 4th and 5th (to control egr via the black box)

[bumstein]

The box in the pic was an SJ50 and has both switches, having said that I have seen some peculiarities on this one such as WT flares (no it’s not an ‘88 crossover).

I have another box which was out of who knows what with a different switch setup, still have to do the forensics to find out what it is.

Edit: here’s a photo of both

[Gwagensteve]

LH box is SJ50.

[bumstein]

Intriguing!!

So the reverse switch is in the same spot but the 5th gear switch isn’t there (or at least it’s not in the same spot).

So behind and a little lower there’s another switch which is plugged on the right hand box. What’s that for?

[Gwagensteve]

The three switches are reverse 4th and 5th. EGR is enabled when the car is in 4th/5th. This wasn’t the case with the NT.

[bumstein]

Cheers for the info

So just to clarify.

The SJ70 box is 4th, 5th and reverse as in the pic below.



In SJ50 you have a reverse switch, what’s the other threaded hole for?

[303zuke]

bumstein wrote:

So just to clarify.

The SJ70 box is 4th, 5th and reverse as in the pic below.
In SJ50 you have a reverse switch, what’s the other threaded hole for?

It's also in the SJ70 box, fitted with rubber plug.
It identifies if the car is in Neutral to cycle the Idle Up circuit when the A/C Compressor kicks in.

[bumstein]

Interesting!! The gearbox on the right has the plug but it’s not threaded (I think)

[Majortob]

I wish I could get a decent pic of our set up.
We think we have identified the 4th and 5th switches, as the have a different plug in the loom.
The reverse switch is on the top facing the passenger side, and has the old type round plug.
I do need to clarify something sorry, it’s actually ON for 1st through 4th, and neutral. And is OFF when in 5th or 6th.

[Majortob]

My replies arent showing up, this common issue for this site?

[bumstein]

Majortob wrote:

My replies arent showing up, this common issue for this site?

First I’ve heard of it but at least they’re showing up now.

Right well that’s a bit strange. What position is the switch in? 1, 2, 3 or 4?

My guess is it’s in the wrong spot. But that’s just a guess.

[Majortob]

3. Yeah it’s got me stumped

[bumstein]

Ok, well the diagram for SJ50 shows that the backup light switch is supposed to be in position 2 (item 9 on the diagram). I reckon it’s in the wrong spot.



The other thing that occurs to me, and I can’t tell you the answer without a gearbox in front of me, is whether or not there are different switches. Ie normally open vs normally closed. I’ll perhaps have a look when I get back home tomorrow

[rexhunta]

bumstein wrote:

The box in the pic was an SJ50 and has both switches, having said that I have seen some peculiarities on this one such as WT flares (no it’s not an ‘88 crossover).

I have another box which was out of who knows what with a different switch setup, still have to do the forensics to find out what it is.

Edit: here’s a photo of both

My SJ51 NT box and Troopys SJ50 NT box are the same as your right hand clean painted box in this photo. Was there maybe a crossover ?

[bumstein]

Dunno!! I might have a look and see if I can pick the 5th gear ratio. Might need a protractor for that though

The clean box came from a ‘85 so it’s a good few years before the ‘88 crossover. That said there’s still some other peculiarities on this one which intrigue me.