I’ve searched the forum and all the posts seem pretty old, so I’ll start a new thread and see what you all think.
I recently replaced the ATF in my '92 imported Eunos. I’d been having that “white smoke” issue for a while and figured I’d replace the modulator as well. Turns out they’re almost impossible to find in the UK. I ordered one via Roackauto, the TN59 as it listed the OEM part number I was looking for.
The pic in the description looks the same as my original, but when it arrived it looked taller than my original. According to “Mike the Miata King” on Youtube https://youtu.be/cdgzilEXQL8?t=466, the tall one is for the 1.8 and the stubby one is for the 1.6 (which is the one I need). I got a refund and then ordered the TM59T. Again the pic in the descripton is identical, but now it’s arrived it’s the taller one again. (Clean = new…dirty = old - also discovered the original didn’t have a rubber o-ring )
My question is, does it actually make a difference? And if so, does anyone have any tips where I can find the stubby one?
Many thanks in advance for any thoughts or suggestions.
Gut feeling advice with no technical basis whatsoever is that the two parts are interchangeable, so the new part will be perfectly good for your 92, 1.6.
Will spend some time later trying to find information to back this idea up or dismiss it but do not expect to find much information either way.
Why did the original supplier accept a return - did they try to get you to try the part?
How would you know if the part was not suitable?
Just looked at the link you sent on Rock auto and clearly they have both types listed for the Miata 1.6.
Assuming the fitment is correct I think that confirms that both parts are correct.
Here is an original part which looks like the style you have received. Apparently when these rupture it causes smoke, so why not fit it and see if the smoke goes away. If it doesn’t the part is wrong or faulty but I bet it works just fine
I believe seller refunded me because the part they pictured was not the part I received. At least that’s what I wrote on their online refund form… I didn’t really question it. And that’s the thing about the link to Rockauto. They show pictures of what I want, but their suppliers send a different looking part.
The link you provided for the “original part” is for a ‘94-‘97, mine is a ‘92. Is there a difference? Again, I just don’t know.
The only thing I’m worried about is how the different sized modulators will affect the timings of when it changes gears. Why else would “Miata King” differentiate between them?
Thanks for that. I hadn’t looked at that shop link before. It kind of confirms that there is a difference for the pre-94 cars. And maybe that high price reflects how rare those stubby ones are to find!
When I get a chance, I’ll put the new one in and see (They actually refunded me without asking to return the part ), but I think I’ll only find the part in the US. When I contacted Mazda dealers over here in the UK, they scratched their heads and said while they could find a part number, no price was listed and had no supplier to order from.
As per the guide…the MK 1 1.6 needs the 1.6 item as the 1.8 needs the 1.8, they are designed the way they are because of where they fit and space. the 1.6 and 1.8 devil parts are available from Autolinkmx5
I’ve now ordered yet another modulator from Autolink. A bit more expensive then the previous ones, but at least they’ve taken the time to differentiate between the part needed for the 1.6 and the 1.8. The only reason I’m going to wait until it arrives to cheer is…the first modulator (bought from RockAuto) showed a photo of what I wanted, and delivered a differently shaped part. Same for the second one bought through Amazon.
i also ordered new plugs, and the very important o-ring.
Well, new parts have arrived…and finally, it’s the right one!
…but I do have one question…
I ordered the o-ring ring to go with it, and it’s the right part number, it just looks a bit big. I would have assumed the o-ring would go around the neck at the base of the threads where there‘s a void, but the one that arrived is just slack and looks too big. Is there a slot on the transmission itself that it would fit into?
Really? Hopefully I’ll be under the car tomorrow, but if ATF normally comes out of the hole that the modulator screws into, I would assume you’d need the o-ring to seal that. Its mentioned on other forums as well, as I’ve been mining any info I can find over the past couple of weeks.
Just to finish this off…I put the latest (and proper) modulator in today and the little car is back to being it’s sparky self!
I also had a look for and replaced the o-ring, but only because I had already bought it and figured, why not.
And for the hell of it, while I was waiting for delivery, I did put in the taller modulator as per rhino666’s suggestion to see if it fit. It did fit, as the threads are the same, and it did “work”, but the gear shifting was slow and passive. I assume because the shape of the can itself is different, but the shifting really reminded me of my old '68 Chrysler 300…really lethargic, like melted chocolate. The stubby modulator has given me back the old bitey, aggressive feel.
Thanks for all the input. And I now have two extra vacuum modulators suitable for for any 1.8 MK1’s out there. Any reasonable offers accepted.
