baff 10 Posted March 25, 2019 Hi guys! I'v been dealing with some idle issues and all the signs led to a vacuum leak. It all comes down now to the PCV valve now. I searched all over and found nothing related to the 2.0 16v 9A PCV valve. There are apparently two types of PCV's blue and black. One that is closed with no voltage(blue) and the other one opened (black BOSH). All this information is related to VR6 so I don't know how much it applies to the 9A . Searching for what I think should fit my car 050 133 517 I found both black and blue. This leaves me wondering, wich is the right one... Quote Share this post Link to post Share on other sites
vw rule 19 Posted March 26, 2019 Hello there, the 16v Corrado's I don't think we have anything like this on the valve cover, the only thing the 16v Corrado's have I believe are two solenoid purge valves, that are normally behind the air filter box, but just in front of the strut. They're ment to open and recirculate the fuel vapor deposits from the fuel canister. Plus one of these valves I think helps with idling. Part number for one of them I think is 026133517 I've sent you a WhatsApp photo of the two solenoid valves from my Corrado, one is (grey) = solenoid valve 1. The other valve is (black) = solenoid valve 2 Also sent you info regarding testing the solenoid valve 1 as that is the main sensor that opens once the engine is up to running temp according to the manual I have. Si Quote Share this post Link to post Share on other sites
baff 10 Posted March 26, 2019 Thanks vw rule! Always on the case with great information! This is what I managed to find out: "All models with gasoline engines are equipped with some form of fuel vapor control device. The evaporative emission control system prevents the escape of raw fuel vapors (unburned hydrocarbons, or HC) into the atmosphere. A carbon (charcoal) canister is used to store fuel tank vapors that accumulate when the engine is not running. On most models, a control valve is used to prevent these vapors from entering the intake manifold when the engine is not running. When the engine is running, these vapors are carried to the intake manifold by allowing fresh air into the bottom of the canister. On vehicles with CIS-E fuel injection, the carbon canister is isolated from the intake manifold by a solenoid valve and a frequency valve. The solenoid valve is ON or open whenever the engine is running. The frequency valve is cycled open and closed by the Motronic control unit to control flow rate depending on coolant temperature and engine speed/load conditions. The canister is usually located in one of the front inner fenders." [ATTACH=CONFIG]96593[/ATTACH] Does this mean that the frequency valve is responsible for idling? Quote Share this post Link to post Share on other sites
vw rule 19 Posted March 27, 2019 Yes I believe the (grey) solenoid valve 1 AKA the frequency valve does help with idling, so if the (black) solenoid valve 2 is permanently open once the engine is running, the (grey) solenoid valve 1 will open slightly once the engine is up to running temp or close to that, I think if the (grey) solenoid valve 1 was fully open at idle, the engine would possibly stall or may run rough. The coolant temp switch will communicate with the ECU and the fuel Governor to determine how much fuel to supply through the cold start injector, plus how long to run the cold start programme for, as this will vary from winter to summer. The frequency valve (grey) should be slightly open at idle or may open and close to maintain correct idle speed along side the idle control valve. These solenoid valves normally last for years, they can go wrong but it is rare. You can test the (grey) solenoid valve 1 AKA the frequency valve, by taking off the vacuum hose to the above valve from the fuel vapor canister, you should feel / hear suction as the engine is idling, if not then it could possibly be faulty or the signal from ECU could be absent ? How is your Corrado idling currently, is it surging or running rough or stalling. Si Quote Share this post Link to post Share on other sites
baff 10 Posted March 27, 2019 (edited) I had a look on my car and the valves are as follows: Black : 05313350 the on/off valve Grey : 026133517 frequency valve My idle is oscillating and with correct distributor timing it sits at 1100-1200rpm. I had to modify the distributor position to min. for the car to idle at 900-1000rpm. I had the spark plugs replaced, leads, rotor,distributor cap, temp sensor replaced, 3 idle valves boght (2 used and 1 new - aftermarket. None of them make buzzing noise. Checked for current and it's ok. I am just so tired of buying them. From what I understand i'ts not mandatory for a idle valve to buzz ). I cleaned the throttle body and will replace vacuum hoses and injector o'rings. The vacuum hoses don't seem to be leaking but I will replace them with silicon ones. Used some carb spray on the injector o'rings and the engine changed note but not that drastically that will compensate for 400-500rpm. I will test the frequency valve accordingly to your instructions and see if it works & check the harness for voltage. Is my understanding correct that the frequency valve should make a ticking noise? The on/off valve the testing should be pretty straight forward I guess... With the engine on I should be able to blow thru the valve form the canister side. Thanks once more for you're help! Edited March 27, 2019 by baff Quote Share this post Link to post Share on other sites
