850 1995 Idling up and down Topic is solved

[misha]

all right Guys. I will order one to Volvo. Thanks.

If your old ECT was original and was working properly...you might re-install it and see how the engine runs.
Chances are that you don't even need a new one.

Don't forget to remove negative battery cable while installing the old one...in order to reset bad fuel trims.

Mine is still original.

[manovlov]

I will do. BTW, Misha, you told me recently that i should watxch out if i would like to replace my gearbox because 1996 models are different that 1995 ones, i could lose cruise control option. Could you tell me more about that ?

[misha]

Automatic?

[manovlov]

Manual.

[misha]

I don't remember that i adviced you about manual transmission.

[manovlov]

Solved. With the advice of Misha, I've replaced the coolant sensor by an OEM one. Everything is fine, now.

Thanks, Misha.

IMG_4183.jpg (236.7 KiB) Viewed 525 times

[misha]

Remember....ALL sensors & ignition parts MUST be OEM.

[abscate]

Just to add a bit to this thread. In English, when the idle speed is changing and does up and down, it is often written that the idle is 'hunting'

This means it is 'looking' for a stable idle but not finding it.

might be useful for searches

[manovlov]

The troubles continue...

I've checked all vacuum lines, replaced the coolant sensor by an OEM one... The issue is still here. The engine goes warms normally, the gauge needle doesn't move, and finally i hear a sort of inspiration noise around the brake booster and then the engine stops.

Add to this, the electrical fan starts as i introduce the key on position before to action the starter. I've replaced the relay, but it wasn't the problem. The fan need to be replaced.

I'm going straight to a big bill I think...

[misha]

Then it is wiring problem for ECT from wiring loom side.

It have to be it...it's a classic bad ECT sensor symptom or it's wiring.

Since ECT is oe and brand new...the connector or wiring for it from wiring loom side is bad.