Coolant Temp Sensor + Couple Other Questions...

February 17, 2012

Hello all!

SO, I have a 1990 GT4 (3sgte), and I'm certainly glad I bought it but it needs a little work... I do have a couple questions, and I'll try to keep them short, but it hasn't worked out that way... I greatly appreciate any answers!

Firstly, I've recently been having idling and revving problems and finally noticed my coolant temp sensor's plug has just corroded to the point of falling off (The red one I believe), but I'm having trouble finding one to fit.

The one on there has a 22mm head, but the part my mechanic got for it (which is what he was told was the right one) has a 14mm head, so I'm wondering if the housing has been changed, or if it's an overseas part(since I don't know whether or not it's an import), or if perhaps in the mean time if I can put something in it's place. I've just got a piece of paperclip in there (the red taped wire) and it fixed most of the issue, but while driving it is VERY slow on takeoff untill it gets to about 2.5-3k rpm (I've got a bigger CT20B turbo on it), and it goes well after that, so is that related? (very complicated question, I know.)

Secondly, it is absolutely terrible upon first startup. It stalls and whatnot so have to give it a little bit of throttle for 30-45 seconds, but I have a feeling that is also related. The odd thing is that if I give it more than just a little bit (not heaps of course, say 17%), the sound of the engine changes completely from the rough idle to a kind of thumping noise until I let up.. I don't really know how to describe it any other way. It'll only do this untill it's partly warmed up, so I don't think it's bad, I'm just curious - Only one way to learn!

THIRDLY... The engine makes a bit of noise when running, but I've been told it could be worn out lifters (a clicking kind of noise in time with the idle), but that's not really the question.. Whenever I turn the engine off, just as the rpm's drop to zero it makes a clink kind of sound (a somewhat substantial clink at that), and it'll also occasionally do it when I first start it up if the revs drop down towards stalling range before I tap the throttle to get it back up.

Lastly.. I've attached a photo of the CTS housing, and if possible, could someone label the parts for me? You'll see why when you take a look... I've colour co-ordinated the wires to where they are meant to go but I'm not 100% sure which piece is which. Please correct me if I'm wrong, but from what I know, the single wire (green) is for the temperature gauge, which is odd because it still works fine..., and the red is for the ECU part of the coolant temp sensor (right?), so what's the one with the question mark? Haha.

Sorry there's so many questions, but I figure I may as well try to get as many answers as I can to fix this silly machine. And also I hope this makes sense, as I copied part of this from another [somewhat inactive] forum then added to it.

Many thanks again!

Adam.