Regarding water pressure
Gagelites Water Pressure Warning Light Kit
As usual mine is still on the bench so I cannot vouch for the quality of the "sender". A meter will enable you to monitor the max pressure and whatnot, but a working light is what you normally need.

I agree, crimps and heat shrink work very well. You can run solder on the inside of the crimp if you are worried about it separating too. Not sure how good that would be if you needed a connector though ;).

I grabbed my stuff from waytek:
Heat Shrink Terminals & Connector Assortment Kit, 115 Pcs.
6" POLYOLEFIN HEAT SHRINK KIT 86 ASSORTED BLACK PIECES - 22288
Wire Terminal Kits | Electrical Terminal Kits | Waytek Wire

If you know what you want though, they have really good prices for bulk items.

The connectors I linked contain solder. Crimp first, then heat to shrink/solder. Very secure.

I'm definitely intrigued Chris. For now I've ordered the water and oil temp gauges, since I need them right now (hard to verify new oil cooler airflow setup is working when autometer is reading 50* high) but definitely interested in improved ways to monitor the car down the road so keep me updated. I saw your circuit diagram on FB, it was wayyyy over my head ;)

-Ryan

How much heat is needed to activate the solder? I use a heat gun for usual heat shrinking, curious if that would also work for these, or if you need a torch..

-Ryan

Nice affordable option to at least know to shut it down as soon as a failure happens.

The benefits of a guage over just a warning light as described to me by Emilio was that seeing how/when it fluctuates can point to the issue - for example, hitting 50 psi? Head gasket is about to go. Pressure drops for a short period as you come off a hot lap and bring it back to the pits but then stabilizes again? Working normally. Doesn't do that? Reservoir may be empty.. etc. etc.
Here's the accutech oil pressure gauge, three-stage warning that you set the values for, and an output for an external warning light. Pretty sweet. (skip to 0:45)

Just as an fyi, since ECUs are being discussed. On the NB, the same 3 wire sensor feeds the ECU and the dash. On the NA, there's a 2 wire sensor to feed the ECU, and a separate 1 wire sensor to feed the dash.

The butt connectors that Emilio linked are meant for a heat gun.

Delcity sells a companion butane torch, which I bought. But I think John uses the big Dewalt heat gun in the shop.

I set the gun on 1100° and go after it until the solder melts. I have never tried the torch.

I used the solder sleeves that didnt have a crimp component when wiring my trailer. The HF heat gun melted the solder just fine on that 35° day that I rewired the trailer.

Is Drifting Racing? | Speedhunters

On a side note, drifting is a competition, but isn't racing :nono:

Often due to loosing a lot of water, and then measuring hot air instead (or is it just for racers around me where that's the most common engine failure).

Or just a fault anywhere in the chain water->sensor->meter->eyes->brain->action.

Ok since this thread is becoming a bit of cover-all for gauge stuff:

Just got my AccuTechs in, (will post some pics/impressions in a bit), one nice element is for oil/water temp, the gauge face is labeled simply with a "F*", and then included is a nice "Coolant Temp" or "Oil Temp" label that you can stick to the mounting plate by the gauge. So the gauge can be repurposed for any fluid, really, without confusingly having an incorrect label on the gauge face.

I've been wanting proper fluid temp gauges for transmission and differential, especially with the relatively unknown variable in my case of the enclosed transmission tunnel and therefore theoretically increased heat introduced from the nearby exhuast - how much we don't know..

So how could one easily introduce a temp sender for the trans and diff? Diff seems easy since the drain plug is horizontal - same way as I have engine oil temp - get an adapter for 1.8" NPT (sender) to the threads of the diff's drain plug.

For trans this option isn't so great since the drain plug points straight down and is close to the ground - back of the sender needs ~1" of clearance behind it. Not sure I have that between drain plug and the flat underbody.

Ideas? I have a 1.8 5 speed, in case there's an alternate hole that could be used..

-Ryan

Drill and tap sump from passenger side?

In thanks for all the assistance and resources that this forum and its users provide me so often, I try to give back when I do have something possibly useful to contribute. So, here are my impressions on the Accutech gauges I just purchased as a result of this thread..

OK so picked these up for $93 a piece from Summit - they don't have them on their site but they can get them directly drop shipped from Longacre, no tax for me in CA and free shipping with the order over $100.

https://www.miataturbo.net/attachmen...ine=1402824654

first impressions are great, look good, precise increments on the gauge faces. As I mentioned above, a detail I like is the face is only labeled with a "F*" and a serparate label for "coolant temp" or "oil temp" is included in the package to stick by the gauge, and this means you can use the gauge for the temp of any fluid without the gauge then confusingly having an incorrect label printed on it.

Wiring:

https://www.miataturbo.net/attachmen...ine=1402824654

Here's the part that I think is a big deal. Comes with a complete harness from gauge to sender, plus loose ends to be connected to power and ground. This takes a lot of the variables for getting the install wrong out of the equation.
The cheap autometers I had came with zero wiring - just spades on the back of the gauge and a spot on the back of the sender for a terminal to bolt onto. This leaves one of the most important elements for accurate sender readings - the wiring - up to the installer, and I'd bet 9 out of 10 installs are sub-adequate. I now know mine was.

Wiring left for the user to hook up is a constant 12V, a switched 12V, and a ground. Switched 12V is for illumination and stepper motor power, and I presume that constant 12V is for the warning light setting memory. This means if you disconnect the battery you'd need to reset your warning lights. BUT, it appears that they have default settings (~230* 1st stage, ~250 2nd stage), so even if you forget to reset them, they still default to roughly the temps you want them at.

I didn't know if the ground wire was used only for completing the circuit for the illumination and stepper motor power, or if it also influenced the sender readings, so to be safe I ran it to the sensor ground on the engine by the FPR.

Here's the Accutech sender with the adapter for the drain plug threads on it, beside the Autometer sender:

https://www.miataturbo.net/attachmen...ine=1402824654

And for reference, here's the sender from the baller Omari gauge I used for testing:

https://www.miataturbo.net/attachmen...ine=1402824654

Function appears great, agrees with ECU. Not much else I need to say since 949 has already put these through far more testing than I can.
One note is that because these use one wire for the switched 12V source for all the gauge's functions, these are always lit when on. At first I thought I wouldn't like that but it turns out it makes visibility realllly good during the day with glare, sun, etc.

The warning light has two user-settable levels - solid light on, then flashing light. Light is pretty bright, if these are mounted in driver's peripheral vision just below window level like I'm planning, they'll definitely get your attention if they come on. Coming from cheapo gauges, I really like this feature.

Currently just shoved them in the air vent holes to verify function, will be making a mounting plate for these that will place them slightly higher and aimed at the driver, but several other things in the works on the car right now that are taking all of my time, so that hasn't happened quite yet:

https://www.miataturbo.net/attachmen...ine=1402824654

Possible..
Would be a bummer to have to drain the $40 of trans fluid I just put in. If I put it in an existing threaded location, I can do a quick switcheroo and lose only a tiny bit of fluid (swapped oil temp senders 3 times this way, only had to replace 1/4 qt. oil)

-Ryan

That's a great price for stepper motor gauges and the nice wiring. Looking at your Autometer wiring . . . well . . . enough said.

It would be nice if the Oil Temp had a bit more range. Even monitoring the oil pan (cooler than a sandwich plate), the needle will be pointed at 1-2 O'Clock on track. Would be better if normal running temp was around 12, but you'll adapt.

The OEM radio connector is a great place to pick up switched and unswitched 12VDC. If you buy one of those radio install kits, you get the plug you need. I'm guessing the OEM radio connector is long-gone on your car though.

They are also available in 100*-340* but that's a little high. I picked the 100-280 for better resolution since I should be shutting down if I get anywhere near 280 anyways.

You could always clock the gauge so the normal op temp is pointing at 12 o'clock

-Ryan

Just drain it into a clean container. Trans fluid is pretty easy to do that with since the drain goes straight down.