UK Car Repair: Stalling when braking, astra cdx, camshaft sensor

Question
Make: Vauxhall
Model: Astra CDX
Reg: V
Engine: 1.8
Fuel: Petrol
Valves: 16
Miles: 50,000

Hi Bill,

My Astra keeps stalling as I slow down and/or come to a stop at a junction or similar as I put the clutch down and brake.

Very occasionally, I can avoid it: As I put the clutch right to the floor in order to bring the car out of gear or change down a gear as I slow, I can see the dashboard lights come on, indicating a stall. I can bring the clutch back up quickly which brings it out of the stall, however, most times it just stalls anyway.

I've tried several types of fuel injection cleaning fluids, with very limited success: It does seem to improve it a little (20%), but then it goes back to its old ways.

I also took it to a garage. They said, after using the diagnostic tool, that it wasn't the fuel injectors that were the problem, it was showing an error with the camshaft sensor. £200 later, I drove the car out of the garage and stalled at the first junction. They said that, ideally, it is recommended that you change the crankshaft sensor at the same time, and this would probably fix the problem. However, this would have meant another £200. I cut my losses and left. The change of the camshaft did make some difference, about 70% better. But, again, it eventually started stalling more and more regularly. Might this suggest a more underlying problem?

It seems that as the clutch goes down, it doesn't let enough fuel through to keep the engine running over in idle. When I start the engine normally, it starts fine, and its idle revs seems fine. The problem only comes about when revs drop suddenly. It's as if its too much of a shock and it cuts out altogether. After a stall, if I try and restart the engine straight away  it often starts, then the revs die again, and it cuts out again.

Of course, the biggest problem that arises from this problem, aside from the fact I'm constantly restarting the engine every time I stop, is the situation when I'm slowing towards a roundabout or junction, I see all is clear, and then begin to accelerate again to pull away. However, the engine has cut and I coast out onto the roundabout or into the road with no power. This has almost caused a couple of incidents, so I generally stop in these instances.

Any ideas would be much appreciated?

Best Regards, John Cliss


Answer
Hi John
I can tell you precisly how to fix this very common problem.
I cant believe a garage couldnt do this.It basically depends on which engine type you have if its a X18XE1 or X18XE, should be stamped on the engine block at the front on a flat buy the head gasket joint.If X18XE1 them remove the air intake pipe and clean with an aerosol carb cleaner all around the flap area inside with a toothe brush the edge of the flap too.
The problem stems from the throttle body area and its lack of breathing or idle air control.If engine X18XE then follow below.
What you need to do is first buy a New Idle Air Control Valve (IAC valve) and gasket.They are about 130 quid but cleaning them rarely works for long.
Also buy (all from a Vaux dealer as they will now what you mean) an oil seperater and clips to go with it also a new breather pipe for the front of the engine out of the cam cover, curved over to a long metal pipe into the crank case.

The procedure is
remove the air intake pipe,remove IAC valve.
If you look in the throttle body you will see all the black deposits, open the throttle flap and with a carb cleaner aerosol and a toothe brush clean it all like mad... get it spotless in there (dont worry about deep inside ,just the flap area).....dont forget the edge of the flap.
Fit new IAC valve.
The oil seperator you have bought needs to be fitted in the new pipe.... cut the pipe so the curved part is missing and the remaining straight bits connect it to the engine breather.
Start the engine when you done this.... it will start but run poorly for a second cos of the carb cleaner.
It should be fine after the above is done but sometimes you need to reset the "base idle"
To do this I'd suggest go to the dealer as it causes the engine management light to come on and if not done correctly can cause surging and all manner of problems.
Hope this has been some help.....dont hessitate to send me another message if you get stuck or dont understand my rather rushed description.
Regards.