850 1995 Idling up and down Topic is solved

[manovlov]

Thanks Misha, i will have a closer look on that.

[misha]

Temperature gauge input is ONLY from ECT,your gauge is dead.

Cooling fan which works before starting the engine is because ecu doesn't know what engine temperature is and it starts the fan to prevent overheating....again...because ecu doesn't receive input from ECT.

It also can continue to run when engine is turned off...that's also another symptom of bad ECT or it's wiring on pre me7 cars('99+).

Since your ECT is oe and brand new...it MUST be the wiring from wiring loom side...somewhere.

It's corroded,broken or shorted somewhere in the wiring loom.

[manovlov]

Temperature gauge input is ONLY from ECT,your gauge is dead.

Hvala Misha. Question : when you say my gauge is dead, how do I repair this, have i to change the speedometer itself ?

[misha]

It is dead because it doesn't get signal from ECT.
Engine dies because ECU doesn't get signal from ECT.

Check the wiring and connector from wiring loom side.

[manovlov]

I need to define the part of the diagram i have to check. These boards may be helpful to some others buddies.

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Hvala Misha

[misha]

In fact...you will need to carefully examine them visually.
Just ECT wiring circuit...leave cooling fan circuit alone for now.

Nema na cemu!

[manovlov]

Yo Buddies,

Manov back on the ring !

Hope you're all fine.

Last winter i've replaced the coolant sensor and of course, as an idiot, the steel seal that goes betwin the pipe and the sensor itself felt down behind the alternator (otherwise, it's not funny...). Today i have unbolted everything to catch this f*cking seal and i got it. I saw the two cables that go on the sensor plug and one of them, the yellow one, was cut. Could it explain the idling up and down i speak since 6 pages of this post ? Am I right to think that the part number on the schema is 7/16 ?

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Thanks to anyone who could tell.


Manov

[abscate]

7/16 is Volvo for the ECT, Manov. Double-check by comparing the wire colours..it looks like the ECT shows two black wires changing to yellow and GR and GR-black at the connector

I don’t remember if GR is gray or green in Volvo diagrams.

[manovlov]

GR is grey.
Live, one is yellow (grey) the second is grey and black.

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[scot850]

Welcome back our friend and great to see you back in on your car! Congrats on your completion of your training and gad you finally were able to hunt this issue down!

Neil.