CLT reading high [Archive] - Turbobricks Forums

bryant

03-19-2006, 03:34 PM

PetesDustyVolvo

03-20-2006, 04:11 PM

New install MS2/2.2/2.25mt - '83 242ti / 530 head/ browntops/fuel only for now...

CLT reading 180f. Can anybody give me the easytherm values for a stock bosch temp sender... this head is from a 91 turbo and the clt is stock.???

thanks!

thats not high

its just about right

search and you fill find... i think its in a thread started by ovlov760 or maybe his name is ovlov740

jimjawz

03-20-2006, 08:31 PM

Mine is sort of "hot" like that too. It sometimes moves sparatically also. Does this happen to anyone else???

JohnMc

03-20-2006, 08:35 PM

180 F? Sounds about like a fully warmed up engine to me. Wouldn't be suprised to see it go higher on a hot day with some spirited driving either.

And really, I don't think (prepare for onslaught of corrections) that the CLT has that much affect on the mixture on a warmed up engine. It's almost exclusively used during the warmup phase to enrich the mixture. But I don't think it makes any difference if the engine is 150 or 250 degrees.

jimjawz

03-20-2006, 08:36 PM

I even tryed a new iat sensor

JohnMc

03-20-2006, 08:43 PM

I even tryed a new iat sensor
IAT or CLT? OP was talking about 180 CLT, engine coolant temp. Not intake air temp.

jimjawz

03-20-2006, 08:53 PM

Volvo calls it a iat...for what reason, I dont know? So yes Ichanged the correct clt sensor :-P

bryant

03-21-2006, 01:37 AM

Forgot to mention that the CLT reads 180f BEFORE I start it...

Boris740

03-21-2006, 12:41 PM

-4°F 15000 Ohms
104°F 1200 Ohms
212°F 180 Ohms

If I short mine out on the stim it will read 170°F

bryant

03-21-2006, 12:57 PM

Thanks Boris,
that is what I was after...

but it sounds like I should ck my wiring, huh?

Does the CLT sensor care which lead is +... maybe I have it backwards, if that is possible???

Bill

blkaplan

03-21-2006, 02:43 PM

I have been running my bosch, with the GM curves, car cruises around 190F. High boost it can get up to 230F

PetesDustyVolvo

03-21-2006, 02:46 PM

I have been running my bosch, with the GM curves, car cruises around 190F. High boost it can get up to 230F

230F !?!?!!??!?!

Mine got to 191 F at 15 psi after I pulled the timing for safety and took third gear from 60 to 120 mph

twice

on a turbo that i hacked together myself

Boris740

03-21-2006, 03:22 PM

Thanks Boris,
that is what I was after...

but it sounds like I should ck my wiring, huh?

Does the CLT sensor care which lead is +... maybe I have it backwards, if that is possible???

Bill

There are two kinds of sensors that I am familiar with. One that I have in my hand Bosch# 280 130 023 has a thermistor connected between two pins.
I think that there is another kind which has two thermistors that share a common ground through the threaded mount. If you have that kind than just connect between the ground and only one of the pins. There may be other variants. Thermistors by themselves have no polarity.

At 30°F the voltage between the ground and CLT will read 3.96V
At 194°F the voltage will read 0.447V The relationship between the thermistor resistance is and temperature is not linear. That is why you need three values for Megatherm

On another note as the temperature drops even further the CLT will start to approach 5V (Vref) because thermistor resistance which is a lower part of the voltage divider, with R7 being the upper part, will rapidly increase. At some point and that will happen below 5V the protection diode D3 will stat to clamp that voltage resulting in incorrect CLT reading at lower temperatures thus compounding the starting problems. B&G recommend that you do not use D1,D2,D3,D4 and D11.