Confused..temp gauge sensor

[anders]

Hi all

Getting som odd temp gauge readings. When i start car from cold, temp gauge rises to ½ mark. When engine gets warmer it tops at the red temp mark. when i dismount the sensor from the tstat house at shows Zero on the gauge. If managed to check for wirering to be switched (ecu temp gauge with coolant temp gauge) but no, everything is in right place.

To shorten the story:

Got an e34 with m20 2,5 engine, car is from 1988.

the cylinder head gasket was replaced because the old one blowed... then i also got a new air intake manifold, tstat housing and so on,,, engine parts where taking from en e30 m20 2,5 1988. So got all new gear from a e30 engine from the head gasket and above. All replaced exept the very buttom part of the engine.

the i investigate engine part at http://www.realoem.com/

and found some interesting stuff.

This is the original e34 tstat setup http://www.realoem.com/bmw/showparts.do?model=HC21&mospid=47373&btnr=11_0790&hg=11&fg=35

it shows that the coolant temp sensor is a 2-pol type

then if we take a look at the part i have installed now from an e30
http://www.realoem.com/bmw/showparts.do?model=1421&mospid=47283&btnr=11_0759&hg=11&fg=35

it shows tha the coolant temp sensor is a 1-pol type.

Is that the cause of all my problems regarding the faulty temp gauge reading?

and if yes.. what can i do about it... can i use another temp sensor, one with more or less resistance?

Please help im really in a pain here...

Greetings..

Anders from Denmark

[genphreak]

I don't know which of the various types might be compatible, however:
2 pole sensors change resistance at two temperatures
1 pole sensors change resistance at one temperatureDifferent ECUs have different needs. If you use the wrong sensor or an ECU otherwise gets a poor reading, economy and perfromance will be reduced (sometimes by a lot).

I would buy the right one (new from BMW) for the car (not the manifold) and go with that rather than waste any time on it: They often go faulty.

To test one, you just need the BMW TIS or a Bently manual to show you the test procdeure, (or it might be searchable on this board).

Good luck, :) Nick

[MikeyMike]

Hello,

look at my post: http://www.bimmer.info/forum/showthread.php?t=24892

I have the same problem, only my car needs an 1-pin sensor, but there is a 2-pin on there.
I changed the cable, and gauge cluster but the problem was still there, so im going to order a 1-pin sensor and see if that works out fine.

I like to hear if it works for you to.

[anders]

so what u are sayng is that i just need to go ahead and order a 2 pin sensor?