Fireindc

iTrader: (13)

Hey guys, just trying to get my car together.. i broke the coolant temp sensor on the front waterneck while working on my car, and i needed a new one. So i bought
Anyways, its incorrect. This thing has 2 prongs, the one on my car has 1. It says its for a 1.6l mazda miata, etc. I cross referenced this a few times before buying it. WTF did i buy? And can I make it work?

Here is just the picture for reference :

Fireindc

iTrader: (13)

I also just pulled it up on Vatozones website.. same thing it seems: http://www.autozone.com/autozone/par...25898_0_18589_

Fireindc

iTrader: (13)

FML. Sorry for this waste of a thread. I do believe i found what i need..

http://www.autozone.com/autozone/par...uestid=1306399



Dandy.. now i get to wait another week to drive my car.. ;(

I'm an idiot. For future reference to any n00bs(like myself obviously), the temp sensor on the waterneck on the FRONT of the engine is just a SWITCH for the fan.

Joe Perez

iTrader: (8)

There are a total of -=> THREE <=- CLT sensors on a 1.6l Miata. The two-pin one goes at the back of the head and feeds the ECU. Next to it is a single-pin sensor which feeds the dash gauge. Then at the front, on the thermostat housing, is another single-pin sensor, although that one is technically a thermoswitch, not a temp sensor, and it controls the radiator fan.

The one in the link is correct for this application.

Fireindc

iTrader: (13)

I <3 you Joe. And your fancy shirts.

Joe Perez

iTrader: (8)

For future reference:

The '94-'97 cars have two sensors, both at the back of the head. It's essentially identical to the setup on the '90-'93, except that the thermoswitch on the thermostat housing goes away, and the radiator fan is controlled by the ECU instead.

The '99-'05 cars are kind of interesting. Physically, they have only one CLT sensor, again located at the back of the head inside the heater-core outlet fitting. However, this sensor has three pins instead of one or two. Internally, this sensor actually contains two elements, which are electrically equivalent to the two sensors on a '94-'97 engine combined into one housing. One of the sensor elements uses two wires on the connector and drives the ECU, the other element uses a single wire (and the case for ground) and drives the temp gauge in the dashboard.

This is one of the annoying little problems with transplanting a '99+ engine into an earlier car- you have to find a new hole to plug the "other" sensor into. Fortunately, most Miata owners are accustomed to exploring new holes.

Fireindc

iTrader: (13)

That is "fortunate". bahaha.

curly

iTrader: (25)

For future reference it doesn't keep you from driving your car, it only keeps you from driving your car at idle for long periods of time. A safety pin can be put in the diagnostics box to turn the fans on full time too, if you'd prefer to error on the side of safety. Forget which pins though. I wanna say GND and TAB, but I could be terribly wrong.

Joe Perez

iTrader: (8)

GND to TFA. TAB sounds the horn.

Braineack

iTrader: (62)

ground TAB. it's fun. your neighbors will love you.

Fireindc

iTrader: (13)

You are sure some helpful ----------ers.

Which is why i've been on this forum.. for 6 years now? HOLY ----.

curly

iTrader: (25)

Arg, I was going to say TAB or TFA.

I've completely rewired my fans outside of the Mazda harness, or I would have tested it for you.

Braineack

iTrader: (62)

TAB is horn
TFA is fan.

bmkpriest

I am actually having the same problem... I was accelerating and all of a sudden my rpms dropped to nothing and my car just shut down, I looked under the hood and saw I broke the engine coolant fan switch and bought the one on the auto zone link you posted with one prong!

(Duralast/Cooling Fan Switch - Radiator (TU146) | AutoZone.com)

I installed the switch and my car still wont start... I'm not sure what it is. I heard spark plugs, camshaft position sensor, fuel injectors, fuel pump regulators and other stuff. I also am not getting an RPM signal... Any ideas?

curly

iTrader: (25)

That switch you replaced is for the fans. Literally, all it does is ground the wire going to it at a set temperature to turn the fans on. Has ZERO to do with running the car.

Start by checking your timing, the belt could have snapped. If that's good, ground all the spark plugs on the valve cover and crank the car to see if you've got spark.

Braineack

iTrader: (62)

What curly said.

that switch is nothing to do with what happened.


you need to confirm: RPMS, fuel, spark, air.

first check would be if the cams are turning, then go from there. Each thing could have a multitude of possible reasons.


but it sounds like your timing belt broke. open the oil fill cap, shine in a flash light and look at the cams, then have someone crank it. I bet they dont move.

zaderej

Hey guys, I know it's been a while since any one has posted here and I am torn between posting in the MS threads but its a question about the coolant sensor.

I am planning on running my ms2 (non pnp ms2e???) in parallel for fuel only, I know braineack and everyone says it's stupid but I have never tuned a car so I am slowly learning.

My main question is this: Can I cut the wire that goes to the ecu for the coolant temp sensor (leaving the switch and dash sensor to do their own thing) without having any spark timing change? I know the coolant temp messes with the A/F ratio but if I am running fuel through the MS then I would assume it wouldn't be a problem but I'm the newb so I should be asking questions.

I know the ms will need iat (have a separate gm open element), O2 (wideband?), and coolant, and I don't know what to do about the coolant sensor so any input would be appreciated.

Joe Perez

iTrader: (8)

It's stupid, and is going to cause you more headaches than it saves.

That having been said, I'll answer your question:



If you disconnect the two-wire CLT sensor from the ECU, you will break a lot of things. Spark advance and idle speed control come to mind immediately, I suspect there are others as well. This is in addition to setting off the MIL.


Presupposing that you really need to share, the correct method is to splice into the CLT line and feed it into the MS in parallel with the stock ECU. This will require removing the pullup resistor from the CLT line internal to the MS, and recalibrating the MS to accommodate the value of the stock pullup resistor in the OEM ECU. This value varies by year, and notes on doing it this way are in this thread: https://www.miataturbo.net/useful-sa...76/#post177420

zaderej

Thank you Joe, I wasn't sure what else the ecu used coolant temp for but that makes sense.

I know everyone says parallel sucks but I am afraid of ******* my pcb or car up because I don't know what circuits to use because everyone has a different method and no one has the same set up on their car so I have a lot of research to do with a lot of broken links...

The the things I am confused about are:
What to do with the fuel pump
What circuit to use for ignition (I would like to follow How to MegaSquirt your Mazda Miata but they say they use the VR circuit which confused me. Or could use your circuit that brings me to my other confusion which is how to wire the thing.

I know I have quite a bit of research to do but it doesn't help when the main page says its old and outdated, too many links are broken and no one has one way of doing it.

Joe Perez

iTrader: (8)

(I can't believe I'm comtinuing to give advice on this topic...)


It's not that it sucks, it's that it's harder. The wiring is more complex, the tuning is more complex, and there are a lot of gotchas.


(What year is your car, anyway? This matters a lot when talking about ECU setup.)




Since your post above indicated that you were only interested in driving the fuel injectors, neither the fuel pump nor the ignition circuit are of interest.




The pages are outdated and the links are dead because nobody has actively updated any information on this subject in many years, mostly because we realized there's an easier way to do it.

Have you considered just buying an MSPNP?