Sticking Valves

Before letting the dealer rip and removing the cylinder head, give us more information- what is the mileage on the car, how is it driven, and what viscosity of oil does it have in it. Did this problem come on suddenly or get worse over time. Is the car better when hot or cold. If the car stalls, is it difficult to restart? Bear in mind you must use the correct oil (10w-40) and a car habitually driven slowly at low rpms is much more likely to suffer than one thats caned.

Typically if you have sticking valves then the car would start normally from cold and run fine for perhaps 1 to 2 miles, but then stall at a junction, and generally run poorly at low rpms. It would not be keen to restart and the engine would spin over faster than normal due to low compression. You may be able to check the compressions semi accurately if you are ready to whip out a plug when it starts to misbehave and screw in the c/tester.

Dont forget a high map reading could be nothing more than a) split pipe- loss of vacuum at the sensor b) faulty map sensor, c) damaged wiring, d) stuck open EGR valve (very common on the ecotec engine) When the ECU receives a high map reading it increases fueling- so your symptoms may just be that of a very rich mixture- you should be able to tell this by smelling the tailpipe.

Hope this helps initially.

Tim..

Try a large dose of Redex is the fuel and into the air intake -- be warned lots of white smoke

This isnt likely to do the cat much good.

Tim..

Thanks for your reply

The car has 76,000 miles on it and is used practically everyday the problem did come on suddenly. The problem tends to be there whether the car is hot or cold but the engine never stalls at all nor does it feel like it is going to.

Last april a new EGR valve was installed along with a new cam belt fitted) because it kept cutting out and the engine mangement light kept coming on and was hard to restart once it cut out so had the codes read at the main dealer and it was the EGR valve proved to be the fault.

A couple months ago of this year the engine mangement light started coming on again and i notice black deposits from the exhaust been left on the ground along with a weird smell coming from the exhaust this time the main dealer diagnosed a faulty o2 sensor which was replaced and things were fine until now. I have looked at the oil we are using and it is made by a company called 'Carlube' and is there gold 15w-40 motor oil and i do notice that smell again comimg from the exhaust without any management warning lights coming on

I hope this helps, and once more thanks again.

du.

The message from " Tim \(Remove NOSPAM." contains these words:

Just make sure it's indoors then.

I'm errr-ing to a faulty EGR valve again- if you have the ability- remove it, fashion a steel blanking plate and sandwich it back on the valve. Try the car again.

Tim..

if it is sticky valves (sound more like a fueling problem to me though) have you tried giving it an Italian tune-up?

Thanks again for all replies,

As i don't know enough about cars (thinking of learning though) do you mean getting someone to take the EGR valve out and putting a steel plate on it and putting it back on with the plate attached to it, and if so what should happen once that is done would that prove a faulty EGR valve and if so in what way. Sorry if the questions sounds silly.

Thanks again.

Yes, yes and yes.

Tim..