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Discussion Starter · #1 ·
hi I hope somebody an help me with this.
I have a zafira gsi with a very strange fault.
its the camshaft position sensor circuit malfunction.
ive changed the sensor and the ecu checked the wiring seems ok I don't know where to go next, unplug the sensor the car runs perfect. plug it in backfiring and wont really start.
what has all my mates thinking is it running fine without the sensor!!
any advice will be appreciated its costing me a fortune.:face:
 

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I think it uses the crank signal and 'guesses' where the cams are with NO cam signal, ie unplugged. I suspect it won't rev above 4k revs.
If the sensor is plugged in and giving a weird or corrupted signal, it just confuses the ECU.
First off, have you bought a genuine sensor from a dealer, or is it a motor factors/ eBay jobbie?
 

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Discussion Starter · #3 ·
hi thanks for the reply, yes bought a ebay jobbie but have also tried a gm one off a mates car (running) and my old one. same results car will rev over 4000 no problem im stumped ?
 

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Rev over 4k when driving or when stationary?

Hmm, very confusing indeed. I have heard of some success of 'leaning' the sensor over to get the round part a bit closer to the cam wheel. There are countless issues with Vectra 2.0 Ecos getting cam sensor issues with rarely any reports back when/ if the cars are fixed. When my MK4 showed the cam sensor fault I parked the car up, ordered cam sensor from a dealer and swapped it the next day and it's been fine for the last 20k, hence the reason I asked about sensor quality.
Have you tried leaving the battery for a couple of days? Also might be worth trying to run it for a few days. Ecotecs require something like "25 good starts" to self-clear stored fault codes.
Does it always show the light when running?
 

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Discussion Starter · #5 ·
hi cheers for the reply
ive been reading another thread about the crankshaft may be loose or cambelt jumped
hes saying the camshaft sensor and the crankshaft sensor saying two different things hence confusing the ecu??
I don't know if im allowed to put links to another forum or not
but it could be do with timing or crankshaft being loose??
sorry if I sound a bit thick about this but im no mechanic
the car wont start when sensor is plugged in it starts but backfires and pops
unplug the sensor the car runs fines after say 10 miles the emg light comes on
new ecu new camshaft sensor
like ive said before unplug the sensor car runs perfect well over 6000 rpms
pulls and boosts fine just the light
just to add ive tried starting it without the sensor then plugging in while running it cuts out
do I spend any more money or get rid? I love this car
 

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Discussion Starter · #7 ·
right bit of a update checked crankshaft pully and it was wobbling like made bolt was not even tight, tried to remove it but to no luck but im putting it down to this, rusty as anything so we are going to get it off on sunday and ill update further, thanks for the advice
 

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Have you checked the wiring? You can damage the wire easy because of how fiddly it is to unplug. Had a similar issue with a mates car, wasn't obvious as it was under the rubber sleeve but one of the wires had snapped at the plug
 

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By the sounds of it do up that crankshaft pulley bolt. If this is the large torx bolt then you'll need to get a new one because they are usually stretch bolts. See Haynes book.
But the question is why has it comes loose? Its a bastard doing the thing up - vibrations alone won't make that bolt come loose.
When was the last time the cam belt was done?
 

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Discussion Starter · #11 ·
hi cheers for the reply
we tightened it up and it was still wobbling( whilst running)
we couldn't get it off so we are going to get some pry bars on it tomorrow
its rusty as hell so think its going to be a nightmare to get off
timing belt waterpump done about 15000 miles ago
but I don't know what caused it to come loose? I mean finger tight loose?
 

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The bottom pulley wheel usually has a rubber ring in it, this is to dampen any vibrations. The rubber on my 21yr old Calibra pulley wheel had started to go. Nothing was loose but over time I noticed that the TDC mark was slowly moving :) . Your Zafira is brand new compared to mine so its unusual for a 'new' pulley wheel to go wrong. I couldn't buy a new one for my car, no more stock - its too old. Pattern part was £200! So I bought a solid ally one instead for £60. You should have better luck with your Zafira as its not that old.

To do the main bottom pulley bolt up you need to lock the crank up so its doesn't move. I fabricated a bar that I could bolt onto the bottom pulley using the smaller outer bolts so it would stop the crank from spinning (ie it spun round and hit the ground), then I could do the large centre bolt up with a long breaker bar.
 

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Discussion Starter · #16 ·
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heres the problem after hundreds of pounds spent a £3 part pisstake
does anybody know the size or where I can get a replacement cheers
 

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[/URL][/IMG]

heres the problem after hundreds of pounds spent a £3 part pisstake
does anybody know the size or where I can get a replacement cheers
Hi buddy, please can you help, I also have tge exact same problem, that u had about tge camshaft sensor, when its plugged in the car battles to start and backfire, as soon as tge cam sensor is disconnected, the car drives perfect except the management light stays on.
Please help
 
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