Opel Zafira 1.7 cdti black smoke out of the exhaust issue

[johnb1]

Hey guys,

I have an opel zafira 1.7 cdti Diesel, which has been flashing engine coolant warning light in yellow/orange, whenever i start it, without even driving the car. However as soon as I start it tends to go on full speed, even though it is not all the time, I would say that it is most of the time.

another point is when I drive it up 120 km/h for example, engine coolant warning light stops flashing. But when it stops flashing accelaration also stops, the car does not increase the speed anymore, no matter how hard I press the gaz/accelarator.

what is more worrying for me is the dark smoke which sometimes comes out of the exhaust, and mostly when I stop at the traffic light, for example. so when I stop without puting the engine off. Now when I start the car and drive for 3 minutes and stop at the traffic light, I see no smoke. but If I drive for 5 minutes and stop at the traffic light I might see the smoke.

The fluid levels are fine in the bottle and there is no sign of any leaks.

The coolant temperature sensor connector is also well plugged in.
Does anyone has an idea of what else it could be?

[valhalla]

The first principle of this type of diagnostic : Fix what you can see

You know that the coolant temperature sensor is faulty, so it is important to replace this unit and/or correct any harness defect between the sensor and the ECM (engine controller module). As a cheap fix, I would suggest you source a new sensor and get it fitted before doing anything else. The ECM needs a good, reliable signal to fuel the car properly, and without this unit working, the engine is going to have all sorts of running problems.

Buy a good-quality sensor, fit it, then let us know how the engine behaves after that. Until you have done this, it is impossible to go any further with the diagnosis.

[wheelnut]

I think you have two problems:

First the light stops flashing at 120 km/hr but, keeps flashing at lower speeds suggests to me that there is air in the system. The coolant level is low and does not reach the sensor until the pump is spinning fast enough to drive the coolant up to the sensor. The problem is probably the head gasket.

Second, the speed does not increase as you press the gas pedal. This is the classic sign of a worn-out clutch.

[sorted]

He doesn’t say engine speed increases but vehicle speed does not when he presses accelerator (which as you say would clutch slip) so I wonder if it is in limp mode.

Links to the running issue, sounds like it is missing at least one sensor input (temp) and so running on default settings and in restricted mode.

[wheelnut]

Apr 8, 2024 20:12:58 GMT 1 sorted said:

He doesn’t say engine speed increases but vehicle speed does not when he presses accelerator...

On reading that again I see your point.