Wankels-Revenge

Hey all,

I just finished reading some old threads about where to tap aftermarket water temp. sender units and watever. Anyway, now i know why the sender unit autometer sent with the gauge doesn't fit ....so i used the stock one. Basically i just wired up my autometer temp. gauge to the stock sender unit.

Here's where the weirdness comes in. I turned the car on to test it out and everything seemed ok...that is until the gotdamn temp. gauge went all the way to 250 degrees F!!!! This was within like 3 minutes of me turning the car on...and i was watching the little orange needle go up the whole time. The engine was still cold..doing its little idle surge thing. The coolant filler cap, the rad, the upper rad hose..none of it was hot. Geez..the coolant wasn't even hot enough to leak out of the leak i have at the coolant filler cap assembly.

So wat the hell am i dealing with here? Is the stock sender unit and the autometer gauge incompatible?
Am i totally screwed and my engine is running at 250 F for some wacky reason?
Or should I keep the old wiring connected to the stock temp. sender unit (in some kind of three way with the wiring for the autometer gauge). I read somewhere that this sender unit hooks up to the ECU...but some people on this forum say otherwise.

So wat do you guys think?
Any help is appreciated!

Wankels-Revenge

^

NZConvertible

Of course they are! Why on earth would you think they'd be compatible with each other? You actually sound surprised that this didn't work.
Please tell me you didn't connect it to the sender on the back of the water pump. That is for the ECU (not the gauge) and should not be touched. The stock gauge sender is under the oil filter next to the oil pressure sender.

Sorry to bust your *****, but you've obviously done little or no research and haven't followed the instructions (I'm pretty sure AutoMeter don't suggest using the stock sender). That's a good way to make costly mistakes when modifying cars.

If you do some resarch using the search fuction you'll see that the best place to put the sender is on the back of the water pump next to the ECU thermosensor. You need to remove the pump to drill and tap a new hole.

Wankels-Revenge

No i used the temp sensor under the oil filter...and i also had a feeling that they wouldn't be incompatible but felt that I should ask that question anyway to get a clear response. Yours couldn't have been any more clear.

I'd rather keep the sensor at the stock location mainly because I have no experience tapping holes into anything..and because the stock location is on the block. I know there is very little temp. variation between the block and the water pump but i'd rather get a block temp. reading.

Thanks for the response.

Oh and btw, Autometer's wonderfully detailed instructions go as far as to say "install water temp. sensor". Not a hell of a lot to go on. It doesn't take a genius to figure out a OE mazda sensor and an autometer gauge won't work together. I didn't want to rule out that possibility.

Gene

iTrader: (1)

Or if you're like me, I have an S5 engine with an S4 thermostat neck installed, and the neck as a tap on it for a 1/2" npt bung. Dunno if that is the stock size of that hole (seems it should be metric on a metric car) maybe it was redrilled and tapped.

Wankels-Revenge

Actually I have an s4 engine so i do have that spot on the thermostat neck. I've actually seen pictures of people who have tapped that location. Thats a good second option i'd say

Silkworm

www.iscracing.net

You can splice the sender in line with the water hose. Just remember to ground the sensor to the block.

LOL NZ, you tell em

PaulC

NZConvertible

No, it's not. The sensor will not see coolant flow until the thermostat opens. This means you will not get a temp reading until the engine warms up, but more importantly, if the thermostat sticks shut you will have absolutely no indication of the rapdily climbing engine temps. Not until it boils and fries your engine that it...

Digi7ech

iTrader: (1)

That's why you keep your stock guage

S4's are good for something unlike S5's.

It may be after the thermosta but hell. It's a whole lot easier than removing the waterpump tp tap it.

I plan to put my guage there.

Maybe even on the stationary cap itself for easy of removal/install.

It won't show correct temps any time before the Tstat is open but it'll work fine once it opens.

Ideally you want it before the Tstat but it depends on how far you want to go.

Wankels-Revenge

Ya i was afraid of something like that happening...which is why i want to utilize the stock location. With a little MORE searching i found a thread with what i needed..apparently autometer sells an adapter. Haha ya i'm an idiot for not finding that out sooner...