Vectra crank sensor

The reason for the difficulty in starting is because it is defaulting to the camshaft position sensor. There is no easy fix,however a small 8m ring spanner will undo the securing torx bolt. There is no need for a major strip down, but access isn't easy. The sensor is located behind the power steering pump, and can be accessed from the top of the engine, with a bit of a struggle. The wire to the existing sensor will need to be cut, and the new sensor wire will have to be rerouted, unless you wish to remove the pump. Replacing the sensor usually takes me about 20-minutes.

Any idea how much they cost? Or how much a garage will charge me?

I would do it myself if it is as easy as you say, but won't have time until next weekend.

I was thinking of taking it to a garage monday morning, and want to know if they try and rip me off. I don't really want to leave it a week, since every time I start it I pour petrol into the cat, and risk flattening or destroying the battery.

Bob

mike

Thanks for the link.

Is the "crank sensor" the same as "Sensor - Crankshaft Speed"? I can't find another sensor, so I assume it is the same thing.

Just wondering why the ECU needs a crankshaft speed and a camshaft revs sensor? Does the camshaft not go at 2x the speed of the crankshaft?

Bob

well lets put it this way if it don't work, the ecu will disable everything. the car will not run. common fault, hence all the links & msgs about them. i'd go for changing it.

It's so you can still get home with a broken cam belt. Bloody good idea....

;-)

Replacing the crank sensor on a Vectra 1.8/2.0 with AC is easier than one without - the plug will fit through the gap between the engine block and pump mounting bracket.

There is a reason for the cable being routed behind the pump bracket - if its replacement is 'bodged' and the wire routed in front of the bracket, it is not shielded from the heat from the exhaust manifold. This can lead to failure in quite a short time. Doesn't take much longer to do the job properly - not as long as having to do it again anyway.

Anthony Remove eight from email to reply.

It was somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Simon Atkinson " saying something like:

I thought there was an emergency pedal driven cable drive in the passenger's footwell to drive the camshaft in the event of a belt breakage.

There is, but if you don't have a passenger...

hello,

It's a shame that most of the prices are missing and I have to email about every single item I want, then wait. It's easier to go to a local main dealer. At least the part is genuine and guaranteed.

The same sensor is often known by different names. The camshaft position sensor's main function is to control the sequential fuel injection more precisely. If the cam sensor fails, the system will default to mpi and limit the revs to approx. 3500pm.

I disagree. Rerouting isn't a bodge. There is more airflow for cooling the wire, at the right side of the pump than there is encased in the pump. Of the many sensors I've replaced, the life of the sensor has not been reduced, if anything, it has been extended. Vauxhall, like othe car manufacturers, have had design flaws in the past, and I would argue that the existing wire routing is one of them. If I had my way, it would be modified on newer versions to run from a flywheel pickup, which have proved to have a far greater life on other vehicles.

And where does the air flow past to get to the cable? Past the exhaust, picking up heat from the manifold on its way past. The pump bracket shields the sensor and wiring from heat radiated from the back of the manifold which is not protected by the heat shield. I have seen countless sensor wires routed in this way, and all have shown signs of overheating (shiny surface to the insulation of the wire or convoluted tubing). Some had even melted completely, allowing the inner conductors to short to each other. I think that the reliability of the sensor is down to the component itself, rather than its location on the engine or its wiring routing. Motronic systems have a crank sensor mounted in the same position behind the PAS pump bracket; the incidence of failure of these sensors is very low IME. I have only had to replace two of these AFAIR, both due to the cable being displaced and rubbing through on the multi-V belt.

What do you feel is the problem with the exisiting wiring routing?

Anthony Remove eight from email to reply.

Failure of either crank or cam sensor will invoke limp home mode and limit engine revs to 4500rpm.

Anthony Remove eight from email to reply.

manufacturers,

We will have to agree to disagree. I have seen a number of sensor wires which have been chaffed, because of their location. To the right of the pump, there is continuous airflow, rather than the swirl which you would find behind the pump. Use an air temp pyrometer, and you will see the results for yourself. Behind the pump, the ambient temperature averages around 80C, whilst the new route seldom rises above 40C. I am convinced that the failure of the cks is often heat related. We are currently experimenting with a vaned air deflector which should assist in prolonging the life of the sensor, this is, however, still in the early stages. There are 12 vectras with this mod fitted, but they have only been installed for 6-months. To date, none of the Vectras have suffered sensor failure...This is still early days. If this does prove successful, we will be working on a system to cool the cps.

To add that you should solder and heat shrink the conductors on the new cam sensor when you install it- choc block is NOT acceptable.

Also before you start anything, pull off the cam belt cover and check the belt tension. These ECU's work on a very tight tolerance window and will light the MIL if the belt is flapping and consequently the cam timing is wondering about with reference to the crank. Usually they light the lamp the instant you go into overrun conditions if it is slack, but check it all the same what with the ecotec's propensity for belt snappage when the wind blows north east and you have black socks on.....(change the belt & tensioners at

Tim..

Snip

Crank sensor (CKP) identifies engine speed and where TDC is. Cam sensor (CMP) identifies when No1 cylinder is on TDC.

Used to change the engine fuelling mode from non sequential injection to sequential. IE Sequentially the injectors fire the same as the ignition firing order (1342). Non sequentially the injectors fire in pairs. 1&4 2&3. So it important to know when No1 is firing (as 1&4 come to TDC together) hence the Cam sensor.

The system can run if either one fails, but goes into limp home mode, revs will be limited.

Garry

Thanks for that.

When the crank sensor failed, it took about 5-10 tries to get the engine started. It seemed to run OK, accelerating fine and ticking over evenly. Revs were limited to about 4500.

Bob