When should the ISV buzz?

[davidhawkins_78]

Morning peps,

Silly question ... today driving to work my Golf decided to have a funny 30 seconds coughing and spluttering right across the rev range.

I pulled over and stopped turned her off and check under the bonnet to see if anything was amiss - all looked ok, so I started her again and the revs were way to low and the isv seemed not to be buzzing.

I checked the connections on the coolant sensor and ISV itself - no change, no buzzing

I left the ISV unplugged just in case and drove fine - but after arriving at work I had another peak only to find the plug had landed on the exhaust manifold and melted an ickle bit grrrrrrr.?

After some jiggling with a Stanley blade the plug now fits - but the ISV doesn't buzz with the ignition on - I can't really tell with the engine running either.

Should it buzz with just the ignition on?? Also, disconnecting the coolant sensor whilst the engine is running doesn't drop the revs, so I'm still suspicious, but the engine was warm.

I've checked all the connections fuses etc so I'm suspecting a faulty ISV ... any help / comments would be gr8.

[Blue MK2]

yaeh with ignition on

[Overseer]

yeah it should buzz with the ignition on.

i had a suspected ISV prob last week (luckily for me it turned out its not gone..) 'performance driven' (vw specialists) had some kit to clean the ISV out. he also said something about giving it 12v to test it.  he said a lot of gunk came out of mine. (but he also said that he flushed something else, i think the hose that plugs into it)

i know if you take the whole ISV off you can try to squirt some carb cleaner through it.

hope this helps.  and hope its not the ISV.. not cheap..  :'(

[davidhawkins_78]

It has been a while since I cleaned it, so worth another look at that I guess.

I'll be dam suprised if it's just packed up though - grrrr.

Mine due this is the first thing to go wrong in the close to 2 years I had her, so i shouldn't really complain!

I suppose I should really stick a voltmeter across the ISV plug to check it's getting a feed before trying to find a replacement. Anyone know the voltage it should be getting - I'm assuming from Overseer's comment it's not a straight 12 volts !

[benjam_in]

mine hasnt worked for over a year! lol

[Blue MK2]

if you need a replacement, ive got one for you so your alrite

[davidhawkins_78]

Cheers blue you're a star !! 

If I do need it what do you want for it ??

[Gambit]

sounds more like the coolant sensor is at fault. ISV's dont usually fail

are you able to switch the blue & black coolant sensors around to see if the ISV buzzes with the ignition on?

i do something similar on 16v's to test the ISV but dont know if u can swap them on 8v's

[davidhawkins_78]

Yeah I must say a straight failure is pretty weird ...

Well I've give the ISV a clean and get the ammeter on the coolant sensor see what we find.

As for swapping the plugs over I'm not sure. That black plug on my car has never wanted to budge either !!!

I'm guessing the black plug puts out a straight voltage and not a variable one???

[Gambit]

i assumed one was for the dash & the other for the ecu

are the senders actual different colours or just the cap's?

senders are a lot cheaper to replace than an ISV