I've been reading posts on this for days, and there is so much information that doesn't seem to be accurate.
I'm trying to get vehicle speed to the ecu so that I can tune boost by gear. I found a bunch of articles claiming that I could get a VSS signal from the back of the cluster, but having taken my cluster out last night, and finding that there was no screw on the RSW terminal, and nothing behind it, I realize I need a different cluster. The cluster I am using is a 1990.
Has anyone found out which NA cars had the VSS sensor? I'm wondering if I simply found a '92 or '93 if the screw (and magnetic reed switch sensor) would be inside? Any solutions you have discovered would be very helpful.

Greg

 

Pretty sure that the '90 (and possibly some '91) cars were the only ones without.

You could do this, and not need to replace the cluster: Fitting LHD OEM criuse control to a RHD 90 NA - mx5cartalk.com

 

It isn't explained in the post, as there are multiple reed switches available from Jaycar, but I think this is the one?
Glass Reed Switch - N.O. | Other Switches | Switches | Electromechanical Components | PRODUCTS | SM1002 | Jaycar Electronics

Should be easy enough to solder this in, but if you're right, Joe, perhaps I could just swap in a 92 or 93 cluster, and I believe there are no compatibility issues with any 1.6 clusters.

 

n/m joe to the rescue.

 

I could, but then I would have to take the cluster out for a photo shoot, but I'd rather take it the next time to solder in a reed switch or a cluster swap to a '92 or '93 cluster. If you want a mental picture, imagine an early cluster with no screw there, just a thin strip of masking tape covering it. I peeled the making tape back, and there is clearly no metal inside the hole, just an empty white hole, so there is no sensor hardware back there.

Also, in the picture, in the post that Joe posted, all four of those holes next to each other (180 SW, RSW , - , and DSW) are empty, just like mine.

 

A reed switch is a reed switch. You don't need to buy it from Jaycar (unless you happen to already live in or near Australia), and you don't need to worry much about the specs. As long as it's N.O. and physically fits into the space available, it'll work.




In my experience, all '92 / '93 cars had the VSS even if they didn't have cruise control or an automatic transmission. They don't have the wire for it in the harness, but the physical sensor is there.

 

I have a 1990 and mine had the signal. It just wasn't wired to the ECU.

I think I even have a writeup on it somewhere. Pretty sure it was the first time Joe P propped me. I felt warm inside.

Sadly it was only Braineack who propped me.

https://www.miataturbo.net/megasquir...6-miata-82518/

 

There, now you've been propped by me.

I had no idea that any '90 models had the sensor. Did your car originally have cruise control or an automatic transmission?

 

No and no, at least no signs of it. There is always a chance that for some reason something was swapped, but the car shows no sign of it. Cluster says 188k, and the car definitely feels like its done that much.

 

^^^^^
This was the post that got me excited to pull my cluster last night. Heartbreak when I went to hook up the wire, that I had already heat shrinked the loom onto, looking so good, only to realize there was no screw there, and on closer inspection, nothing inside either. I'm wondering if this is a regional thing, perhaps because mine is a Canadian KPH car they did things differently, I don't really know. I found a 92 cluster for sale (although the speedo is in mph,) and I'm not sure how possible it is to swap the VSS from one to the other, but if it is just a simple magnetic switch, it shouldn't be that hard to swap it over into my '90 kph cluster.

 

That makes me sad. Please take pics of the lack of stuff behind and feel free to add to that thread. Maybe mine did have a transplant at some point.

 

OK, I've ordered 5 glass reed switches (N/0 and 14mm so it should fit, I hope) for $1, free shipping from China, and I think I'll also order the MPH cluster missing its lense on ebay so I'll have some OEM parts to try to swap in, and $1 of reed switches to try too. I will post pics when I have something to post on this topic (when stuff arrives and it's time to actually do something.)
Interesting that there is a wire in the cluster harness, going to the lead that the RSW screw is on, even though there is no sensor.

 

Ok that is totally backwards. Usually there is the RSW screw but no wire in the cluster harness. Either something screwy is going on with your car or you knuks are just weird.

 

Oh, Canada...


Also, in some parts of Canada, milk bags are labeled in both English and French.

Same goes for the graffiti:

 

^
Probably the latter

I wasn't sure, from reading people's posts, if the wire was there in all of the cluster harnesses, but just never went to the ECU (dead ended somewhere,) or if there was actually an empty slot on the harness. There is definitely a wire in the slot on my harness, and it's actually a slightly larger gauge that the other wires on that plug, and is definitely OEM looking (bluish green with a reddish stripe and some silver ovals on it, if I remember correctly.) so I wonder, once I get this reed switch in, if I should try to find it in the ECU harness, or just run a wire, and cut the one at the cluster harness, as it obviously has been doing nothing up until this point.

Dimitris has straightened me out on which pin to send this into my MS3Basic built by him, so hopefully boost by gear is in my near future.


Oh, and where I live in Canada, we don't buy milk in bags, that's an east coast thing, Joe, hahaha. We buy our milk in cartons like normal people out here on the west coast.

 

I forgot about my recently completed "Miata Lamp," bet that will have the sensor in it to harvest!

 

I had linked to this but realized his issue was beyond this.

 

Ok, problem solved! I harvested a sensor out of the cluster lamp I made.








It really is just a little glass magnetic reed switch with a couple metal tabs soldered onto it. Ran a wire to the pin, plugged it in, took a drive, and guess what, accurate vehicle speeds! Set up my gear ratios and tire size, and guess what? Accurate gear readings. It's a little late here now, but boost by gear tuning time is in the near future!

Oh, and here is a pic of the cluster before, with all four of those holes empty where I ripped off the masking tape.




I guess they figured instead of putting a VSS into my car at the factory, they would just cover it in masking tape so no one would notice.

Thanks for your help, guys.

 

Gladd to help.

 

The harness, with the wire that apparently should not be there.<br >