Very High Idle when engine is cold

[Liamuk]

hi, like the title says, Ive had this problem on my golf for about 3 months now, and no amount of tinkering will fix it, ive even gone as far as replacing the carb, which seemed to cure it for about 2 weeks, then the problem came back, although not as bad.

What happens is that as soon as i start the engine and its cold it idle's at 3000rpm for maybe 5 minutes or so, making it differcult to drive, and making traffic lights a noisy and embarrasing situation!.

it has been worse, at 1 point , it seemed that the throttle would stick fully open randomly as i was driving, right up to 6000rpm, a few hard kicks to the accelerator would fix it, till it decided to stick again, and well, i had the carb replaced, which fixed it for a while... and now its doing this high revs when cold.

im just wondering if you guys have any ideas what could be causing this ?

also, ive been having this problems before this "petrol contamination" fiasco raised its head... although i do get the majority of my petrol from tesco.

oh also, i have a L Reg 93 1.4L Golf (Ryder so the log book claims!)

[EvilScotsman]

Take the throttle cable off and hold it vertically then squirt as much wd40 through it from one end as it will allow. Do this for a while and leave it to soak through. WHen its nice and loose, re-fit it and your problem should be gone

Or you could just fit a new one but they are dealer only would you believe!

[Liamuk]

the throttle cable it has on it at the moment is only a few months old, although it did only start doing this after the cable was replaced...... hmmm

i think im buying some wd40 today then!

hope this works

[EvilScotsman]

if its new then the routing may be the problem.

To tell if its the cable or the carb, disconnect the cable at the carb end and start the car (if it starts without throttle use) and rev it from the carb by hand - if it revs ok and drops immediately to idle then the cable is at fault, if it still sticks its the carb - maybe a dirty butterfly, broken return spring etc.

If it has SPI (single point injection) then it still looks like a traditional carb but is actually only a throttle body, and may have a throttle control solenoid which can be faulty and stick when revved. If it does you can work around it by warming the engine a bit from cold, then remove the plug from the TCS when running - keep it off till you get a new one - and it will not stick anymore (doing this when the engine is hot will make it lumpy when cold as it cant go to fast idle, doing when stone cold will result in high idle when hot)