Taken from this months edition of my fave mag, CAR MECHANICS:-
One of the most common problems affecting these engines is stalling.
most usually the owner will complain that the engine is cutting out approaching junctions, particularly when hot.
The solution is a number of modifications, all of which are geared to reducing the amount of oil contamination
affecting the engine and in particular, the idle control valve. the first is the fitting of a breather box.
this component(part no. 9201848) is designed essentially as a filter to remove the undesirable oil and carbon particles
which find their way up from the sump and into the rocker cover. from here of course they get sucked into the idle
control valve, where the fun really starts. The box costs around £10 and is simply fitted into the front breather
hose. after this you must check and possibly replace the idle control valve itself. An improved version was introduced by
vauxhall and is simply denoted py the prescence of an "x" at the end of the part number. the number is stamped on the end
of the component so you`ll need to remove it to have a look. if the x is not there then the component must be replaced,
so the owner of the car wont be pleased because new ones cost about £160! if you find that the modified one has been
fitted then your next suspicion should be that the components performance has been inhibited by contamination
within. youll need to remove it so it can be thouroughly cleaned, and its advised that you use very aggressive carb
cleaner if its going to have any effect. Next clean out the throttle body with carbourettor cleaer and a toothbrush,
frequently cleaning out with a clean cloth. take your time and do this right. The basic throttle plate setting should
be raised as well. ideally this should be done using the voltage output from the throttle position sensor as a guide,
but, if you havent got the equiptment or time to adopt this textbook approach a more immediate solution involves
opening up the base idle control and screwing by one complete turn( with engine off) this normally this brings idle
performance up usefully, but if this causes tickover to sit above 800 rpm youve overdone it. back it off half a
turn and it should be fine. another potential problem that can contribute to this fault is breather pipe blockage
there are a number of importat tubes running into the throttle body and inlet manifold and all are susceptible
to contamination. one in particular, which attaches to the back of the throttle body via a brass fitting suffers
badly. its often the fitting itself that gets clogged. blow all tubes clear with an airline having disconnected
both ends first. it also can help to remove rocker cover and remove all traces of crap, then flush engine and fit
a new filter and good oil. (by the way, shell at carmondean in livingston are doing mobil 1 for £10 for 4l! i cant
get it at double that trade!) The final action if all this fails is to take it to a dealer and have software update
. because the frequency of updates eans that older cars can be running software thats been supursceded many times
, consulting dealer is the only way to get this this checked and rectified, and its only £35.
the other common fault is intermittant power loss caused by either a duff camshaft or crankshaft sensor.
Well, good luck ecotec boyz and girlz!
information taken from november 2001 CAR MECHANICS magazine. that issue also has lots of other good vaux stuff in it , so go buy it if u found this helpful