ISV question ???

[bulk66]

How can i tell if my ISV is faulty on my 8v gti can i put a meter on it and tell that way and when the car is running if i unplug the valve should there be a big change in the way the car runs because i tryed this and there was no change. When the cars warm the revs go up to 1500 rpm but if i give it a couple of revs they go down to 900rpm then if i rev it again they will go up to 1500 again

[raferackstraw]

if i unplug mine on the valver the engine dies straight away. what your describing can be an isv issue. take it off and clean it out with carb cleaner until the liquid coming out is clear, then allow it to dry and give it a squirt of wd40. refit and run engine, it can take a while after cleaning for the engine to settle to a steady idle again

[bulk66]

Cheers mate i did give it a quick blast with some carb cleaner at the week end but i didnt leave it to dry and i didnt put any WD in either so ill give it another try. My mpg pretty poor aswell only got about 50miles out of £20 last week would a fooked lambda sensor affect idle speed in any way???

[raferackstraw]

dont know about digis mate but im sure fubar lambda puts ecu in to safe mode so it runs rich danny p is the man to ask

[theclash]

you wont have a lamba but you will have a blue temp sensor this sends info to ecu worth changing if you are having running problems about 15 quidd from vw dealers (dont get pattern part),also check for air leaks if your idle is erratic check all vac hoses in engine bay for splits/perishing you can buy a meter length from gsf for a couple of pound and cut it to suit,check rubber bung on rocker cover also worth changing as they can split where it sits inside the rocker,check wiring to throttle switches as this can snap and finally check your throttle cable isnt to tight, all these can cause your idle to fluctuate. as for your isv turn ignition to the on position and feel the isv it should buzz.

[danny_p]

sounds like temp sensor is duff to me.

worth checking for air leacks as well.

ISV should ahve an average current draw of 420mA when working correctly on an up to temp engine ( some dmms don't like being asked to measure pwm signals tho some are fine )

[bulk66]

Over the past few days when i get to work temp light has flased even though water temp ok...... Do you have a part number and where is the sensor....

cheers chaps....

[raferackstraw]

if light on dash is flashing check coolant level sensor on expansion tank, if you bridge the pins on the cable the light on dash should go out, which would mean a duff sensor, if light still flashing after bridging then trace and check wiring

[bulk66]

Right ive sorted the hunting revs i took the idle adjuster screw out all the way and gave it a blast of carb cleaner in the hole as per the guide and it sorted it. Ill still get a temp sensor and fuel filter for the old gal coz im in a good mood now