AE92 with silvertop gauge issue

[deaf_rattle]

OK, silvertop is in and everything running fine, just a few niggles to sort out now.
the one im most confused about is the engine temp gauge. afer abotu 2-3 mins of running, it shoots right up to above red hot.

we have pressure tested the coolant system, that was perfect, we bled the system, there is no air in there. there is currently no thermostat in there and the fan is constantly on.

we used an infra red thermometer to read inlet and outlet temps and after about 10mins of 2-3000rpm there temp did not flicker past 80 degrees, which is what you would expect im sure with the thermostat not in and the fan running the whole time.

I am 95% sure i have the right sensor from the old redtop in there to match the gauge.

has anyone got any suggestions? i really dont want to have to put an aftermarket gauge in there.

cheers

[noodlebut]

it could be possible that the ae92 coolant temp sensor is a "Normally Closed" type... where as the silvertomp coolant temp sensor is a "Normally Open" type.. which maybe why your getting a bad reading on the gauge...

in other words make sure your using the right coolant temp sensor for the right gauge, see if u can use the CTS off the original motor that was in the car.

other wise get the ohmmeter out and start measuring resistance....

and just a question... why havnt you got a thermostat in there?... get one in there!

[-GT-]

Ah, i had this exact same problem when i did mine, it was a while ago, struggling to remember exactly how i fixed it, it was definately wiring, i tested my senders (old & new) in hot and cold water and same symtoms every time.

There was a thread on the old forums where i described my symptoms, see if it sounds like yours, here;

http://forums.toymods.org.au/index.p...a8bc23f5394d4f

Edit: Well, i just read that thread and realised that i didn't actually let anybody know how i fixed the problem back then

But, i think my hazy memory has finally dug this up; the gauge in the dash actually has three wires running to it - power, the signal wire to the sender in the thermostat, and another earth that acts as a damper on the gauge. I ended up pulling my dash out, finding this wire, cutting it and earthing it properly somewhere handy to check if it fixed it, and it did. I ended up just earthing it somewhere behind the dash and its been fine since.

Not sure why the problem started, but seeing as its happened to you too its probably that this 3rd wire runs through the body loom near the computer and we both missed it in our wiring. I checked and re-checked and assumed it was a just a bad earth that developed at the same time...

Anyway, hope that solves your problem; check that wire is earthed securely!

[Talasas]

I've seen this on an AE86 which had a 100kW conversion. The wire for the temp gauge was frayed and not well connected and it caused fluctuations in the reading, though mostly it would drop to cold so I'm not sure why it jumps to hot for you...

[sideshow]

the temp gauge earths thru the white/black wire on the plug behind the console/stereo area

this is a common problem i find when people wire these in and dont know 100% what to do

and its only on ae92s

[-GT-]

So how'd it go? Get it sorted?