|
thanks Dynamic Dave...yes it is the Ecotec...any additional info on valve cleaning welcome
|
Hi, what is happening is that the gunge in the valve is holding the revs above normal idle. The throttle is shut and the ECU sees that from the throttle position switch (TPS).On these (Simtec 56) and most management systems when you are driving and lift off to decelerate the ECU sees a closed signal from the TPS but notes that the engine speed is above 1300(ish) rpm so assumes deceleration and closes the injectors off. When the engine speed reaches the 1300rpm threshold it reinstates the injectors to 'catch the engine to idle. Your ISCV is holding the revs on or near this threshold, so, at 1700 it shuts the injectors, engine decelerates, dips below 1300 then the injectors go on and immediately the revs start to rise until about 1700 then the injectors go off again etc etc. Finally the ISCV frees itself and because the motor is fully retracted cannot wind the sticky valve open again fast enough to catch it.
Primary cause for all this gunge is lack of regular oil changes plus the small breather pipe between cam box and inlet manifold gets blocked and its too much of a fag for most people to clean as you have to move the throttle body off the manifold (makes it a doddle to clean), remove the banjo union from the manifold and clean it with a 1.5mm drill then fit a new pipe. Wash out the valve and the 'business end' of the motor and spray some WD40 into the end of the motor.
--
Simplicate and add lightness!!
|
|
|
|
I *might* have a link to a website with some cleaning instructions.
snipurl.com/mdxl
and
snipurl.com/mqya
and
snipurl.com/mqyd
|
|
Thanks Dave, fully understand what's needed now...Will do this once bought carb cleaner and gasket, and report back on success
|
|
|
|
