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Discussion Starter #1
Just a quick question - the coolant temperature sensor for the engine management - threaded into the top of the thermostat - what colour is the plastic top that the blue plug fits onto? This is for a 1998 phase-1 Twinspark Spider, Bosch 2.10.3 (the earlier one with EGR).

Mine's green. I think it might be wrong, because in Alfadiag or AlfaOBD, the Motronic ECU seems to be seeing a very low coolant temperature (think it was about -42 degrees with the engine off and sitting at about 25 degrees). This probably explains the lumpy sound to the engine running and maybe even, if I'm lucky, the injector warning light coming on very briefly a couple of times.

It would also be useful to know what other engine applications use the same sensor - not my 156 TS (for example; it has a four-pin plug), but I'm thinking perhaps 164 V6 as that has a Motronic sensor with a blue top, two-pin plug.

-Alex
 

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Discussion Starter #3 (Edited)
for the CF1 IIRC it's blue
Thanks, that helps to back up my idea that mine's wrong :)
Seeing a blue plug fitted onto a green sensor got me wondering.
Then I remembered the readings I saw when I was playing around with the diagnostics weeks ago (engine not working), and this all tallies with the engine oil drained out having a lot of petrol smell in it.

The plot thickens, I reckon someone replaced that sensor to try and fix some other fault, but actually caused a new fault that went unnoticed...

Hopefully the service manual will include a resistance plot for the sensor and hopefully this will turn out to be the same as a spare 164 one that I'll find in my garage tomorrow.

-Alex
 

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Discussion Starter #7
Been trawling through my images and mine was green on one of my engines, the original to my GTV.

But I am sure the sensor in my 155 is blue which is the same engine and setup.

http://i246.photobucket.com/albums/gg92/explosive-alfa/d77153cd.jpg
Aha! So mine is possibly original after all.

Well, maybe mine's just faulty... :lol:
I tried cleaning its connections.

Thanks Turbonutters also :thumbs: There are very few 145/146/155s here in NZ but I'm off to a specialist tomorrow for wheel alignment and airbag ECU reset, so we'll see what sensors we can find.

Very quick replies you guys, it's 1:50am here...
-Alex
 

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According to the workshop manual...
The temperature sender attached to the stat is L10 and is for the temperature gauge and high temp warning light.
This should measure between 525 - 605 ohms at 60 degrees C and 195 - 245 at 90 degrees C

The sender that tells the ecu the coolant temperature is S7 and should measure between 2280 - 2720 at 20 degrees C and 292 - 362 at 80 degrees C

Is this the same sensor? NFI!
Theres a detailed image of where L10 is, but S7 is on one of the vague, "its in the engine bay" diagrams..

I guess you could unplug the one on the stat, which should make the dash guage stop working, and see if alfagdiag gives a reading..
 

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Just a quick question - the coolant temperature sensor for the engine management - threaded into the top of the thermostat - what colour is the plastic top that the blue plug fits onto? This is for a 1998 phase-1 Twinspark Spider, Bosch 2.10.3 (the earlier one with EGR).

Mine's green. I think it might be wrong, because in Alfadiag or AlfaOBD, the Motronic ECU seems to be seeing a very low coolant temperature (think it was about -42 degrees with the engine off and sitting at about 25 degrees). This probably explains the lumpy sound to the engine running and maybe even, if I'm lucky, the injector warning light coming on very briefly a couple of times.

It would also be useful to know what other engine applications use the same sensor - not my 156 TS (for example; it has a four-pin plug), but I'm thinking perhaps 164 V6 as that has a Motronic sensor with a blue top, two-pin plug.

-Alex
Having a similar problems with over feuling and emissions, Was this the issue in the end?
Mine is also a phase one (1996) with a green temp sender but blue plastic plug on loom. No egr valve I can see tho.
 
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