Vectra crank sensor

Thanks to all who helped me find the diagnostic socket.

I got me flash code. Trust me to have the 4 digit ECU, each starting with 0
(10 flashes), yawn... anyway, the error code it flashed repeatedly was
"crank sensor"

1) On a Vectra 2.0 16v R reg with AC, how easy is it so change the crank
sensor? Is it easy to find, and to get to?

2) Is it the RPM sensor? cos the traction control light was lighting up as
well. And it takes about a minute to get it started. It seems to have
trouble starting when it doesn'n know the crank speed. Carbs used to do
just fine. Isn't technology brilliant?

3) Any tips on getting it started easily for a few days until I can get the
bits or get to the garage?

Bob

 

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

 

www.autovaux.co.uk

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.

mike

 

Bob Smith said:

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

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.

 

Grimly Curmudgeon said:

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.

 

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
36k intervals !!!!)


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