hi all my misses bought a n reg polo few weeks ago from a side street dealer an has been having a couple of strange problems and has been back to the garage 2 or 3 times now

so heres the latest its got me stumped

run the car up to normal temp the leave idling until rad fan needs to kick in when it does the car starts to vibrate like its running rough but heres the strangest bit

she can take the key out of the car and it will stay running until the fan stops

any one any ideas on that dodgey wirirng, timing, ghosts in the engine

o well looks like noone else can work it out either

i know a big hammer or my second favorite a lighter

u mean the fan stays on?, I dont remember my MK4 but when I had a MK2 if the fan was running and you turned the engine off, it would keep going until it had finished. So if the MK4 is the same as the MK2 maybe thats a ok thing. I mean as least the fan is cooling the engine instead of cutting out midway and not cooling it properly.

But someone else on MK4s should be able to tell you a little more on that. Hopefully someone will along in a minute to confirm that lol.

Running rough on idle could be a number of things, but the first port of call for most people is to give the throttle body a clean, as cack gets stuck in it and causes it to stick hence the rough idle.

your message reads as tho the engine stays running? is that right or is it just the fan?

If the engine stays running you have a wiring fault between the ignition switched circuit and the fan circuit. The fan is directly connected to the battery so it can stay running after the engine is switched off until it cools down. If it connects to the switched live somewhere it will feed the rest of the car through the fan switch even when the key is out. Lumpy running with fan on may be related. Are there any accessories that have been added or maybe some non standard looking wiring? Could be something like an aftermarket alarm using the fan connection as its permanent live.

is it a diesel engine?? there is a possiblilty this could happen if there is a problem with the wiring on the injection pump

hi guys cheers for replyin

your message reads as tho the engine stays running? is that right or is it just the fan

yes the engine stays running without the key in ignition

Running rough on idle could be a number of things, but the first port of call for most people is to give the throttle body a clean, as cack gets stuck in it and causes it to stick hence the rough idle.

well il clean this out anyway as it wont do it any harm

If the engine stays running you have a wiring fault between the ignition switched circuit and the fan circuit. The fan is directly connected to the battery so it can stay running after the engine is switched off until it cools down. If it connects to the switched live somewhere it will feed the rest of the car through the fan switch even when the key is out. Lumpy running with fan on may be related.

ok thanks i will have a look into this,

Are there any accessories that have been added or maybe some non standard looking wiring? Could be something like an aftermarket alarm using the fan connection as its permanent live.

the stereo wiring and also an amp wiring look a bit suspect i wll rip it all out and see what happens

is it a diesel engine?? there is a possiblilty this could happen if there is a problem with the wiring on the injection pump[/i]

1.3 cl petrol