16v revs won't drop!

[jocarl11]

Hi, when I rev my 16v from hot or cold the revs either won't drop at all or very slowly decrease to normal idle speed! I have cleaned the isv and even replaced it but it's worse if anything, also when I disconnect the isv and disconnect the isv breather from the main intake hose and blank it off the problem goes away? Any help will be great as I've spent ages on this! Thanks.

[tony_ack]

First check the CO and idle are set correctly as per the guide in the maintenance section.

If that doesn't solve it, my money would be on the ISV controller or wiring, which sits behind the centre console.

[bodga]

clean the three temp sensor connectors on the R/H side of the head, 2 of them send temp readings to that ECU behind the centre console.

i had a similar problem:


http://www.golfgtiforum.co.uk/index.php?topic=160322.msg1478476#msg1478476

[jocarl11]

I have already set up base idle and co and the temp sensors are all ok, also the micro switch is working fine. I have heard the isv controller also controls the overrun? So this should maybe be my next test!

[rubjonny]

check the top throttle linkage arm is moving freely. i had same issue and it was down to that arm, was gummed up so not always returning enough to click the switch. remove top 13mm nut and it comes off, cleanit up grease then refit. take care when putting it back on, really easy to get spring caught in the plastic washers.

also had problem on my cabby, on that one it was down to a stiff throttle cable. took it off and sprayed a bit o silicone spray lube down it, sorted.