Cavalier engine sensors - chris madley
Please can someone out there help.
I have an Mreg Cavalier 2 liter Ecotec motor. Its fairly high mileage at 135000 but has a full service history. I have owned it for the last 35000 miles and it's now on its 3rd camshaft sensor and appears to be needing it's second crank sensor. Is there any reason why these should go so often.
Also while the car appears to run with a failed camshaft sensor am I correct in supposing that the crankshaft sensor failing will cause the engine to stop. In all other respects it has proven to be agood car.
Thanks in anticipation Chris Madley
Re: Cavalier engine sensors - Dave Y

This subject has been aired a number of times in the past so a search on past threads might help. Like you I had an M reg 2.0L Cavalier that went through several crank & camshaft sensors. It will run even though both are showing faults. No-one seems to know what the problem really is though the local Vauxhall dealer reckoned that as they age the wiring loom becomes sensitive to electrical spiking and the sensors give fault warnings. Their solution was to replace the wiring loom (£500) but warned that this doesn't always cure it. A lot of the time the engine management light will come on but the car will run normally. However things can get worse and they can start misfiring; mine used to be OK on starting but would then stall as I pulled across junctions. Sometimes they can be difficult or impossible to restart - I had to be recovered from near Lincoln once since I flattened the battery trying to restart.
Just a hunch but is your battery on its last legs? I noticed that after recharging the battery on mine it seemed much better & I wondered whether the whole electronic set-up is sensitive to a low battery output but this is a long shot.
Replacing these sensors costs a fortune and I eventually got rid of it.
Hope you get it sorted!
Re: Cavalier engine sensors - mike walker
I used to run, from new, an M reg Cavalier SRi with the same engine type, always Vauxhall serviced.
At about 90,000 miles I had the same kind of problems over about 4 months, EMS warning light on, and then new camshaft and crankshaft sensors fitted by a Vauxhall main dealer which soon stopped working.
Finally, when the dealer wanted to change a wiring loom for no obviously good reason, I sold the Cavalier and bought a Toyota.
A pity, because it was in many ways a nice car and had been reliable.
The technician staff at the dealer seemed to quickly arrive at the limits of their knowledge.
Sorry - its not much comfort!
Re: Cavalier engine sensors - chris madley
Thanks for the reply, unfortuneately I don't think the battery should be the problem as I replaced last year. Since original posting I have heard that Vauxhall modified the cam sensor but I would have thought the recent ones I have had fitted should have been new style, does anybody know how to recognise anew one. Thanks again Chris
Re: Cavalier engine sensors - Andrew Hamilton
Intrigued. 'Wiring loom sensitive to electrical spiking'. Suggests failing insulation or wires damaged by bending too tight at corners causing fatigue failure. These should be detectable by multimeter and flexing cable.
Re: Cavalier engine sensors - Andy P
Same problem. My '95 SRi 16V required a new crankshaft sensor. The dealer broke the first trying to fit it. When they did manage to fit it, it lasted less than a year before it failed again.

On top of that, I had endless problems with the EGR valve.

Finally, I'd had enough and replaced it with a Honda Accord. Now I know how awful the Cav really was....


Value my car