UK-POLOS.NET - THE VW Polo Forum

Hi, some top euro style polo's kickin around over here.

I dont own one ive got a Bmw E30. My kid sisters just got one tho and its not the best ever. It seems to be way over fueling, kicking out unburned fuel through the exhaust. its a 1.0l running the standard carb. Am i right in thinking that the electronic choke has broken (this happened on the bm)? does someone know a fix? its been stood in a garage for about a year and was fine before it went into storage.

Cheers guys
Si

Hi,

From what I can remember the Mk3 Polos don't have an automatic clutch exactly, they get information from temperature sensors and the ECU adjusts fuelling to match.

Does the problem get better as it warms up?

It could be the blue coolant temperature sensor, this is a common fault with Mk3s. If it's giving the wrong resistance it can cause all sorts of fuelling problems.

It's cheap and easy to replace too, look under the dizzy and there are two plugs, one blue and one black. Pull the blue one out, release the spring clip and the temp sensor pops out. On mine I didn't lose much coolant at all, though I did lose a bit.

These cost about £9 from German Swedish and French.

Nice BM by the way.

Cheers for the reply mate.

If I leave it runnin for a while it will run right for about a second when its warmed up but then sounds as if the choke kicks in again.

What should the resistance over the sensor be?
I'll get hold of a new temp sensor and keep my fingers crossed.

Looks like a nice clean polo you got there mate. top stuff!

Um, off hand I don't know. I'm sure it's been posted here somewhere though.

Someone will know anyway... but I'll have a look in a mo.

right ive just changed the temp sensor and its a bit better now. only thing is now its as if the jet i blocked in the carb but its not because ive recently cleaned them. it will rev pretty nicely until the pedal is at a certain position. if i floor it it will rev fine.

any ideas guys?

Cheers
Si

I know this is true of GTs, as hardhitter was doing this to my car yesterday.

Try running it till it's warm, then with it idling open the bonnet and disconnect the blue sensor.

Listen to see if the revs raise, if this happens then it's telling you that all the sensors are working. If not, or if the revs drop then either there's a faulty sensor or you're carrying an error log in the ECU.

To clear this you need to unplug either the ECU or the battery overnight. Run it till it's warm and disconnect the blue sensor again. If it's still not doing it, then you've got a faulty sensor somewhere. If the revs raise then your sensors work and maybe it'll be repaired.

If this all works properly, then your problem is elsewhere, though where exactly I don't know!

Hope this helps!

What reg is it? You keep saying the word "carb" but if its a mk3 like mine and alex's (krupa) then it will have fuel injection. The older round headlight polos all have carbs is it one of them?

Edited to say, well if ur in the mk3 secion then the car is probably a mk3! Anyway, If changing the blue temp sensor hasnt cured it then it may well be the lamba probe (the blue temp sensor should read about 200-300 ohms at 90C by the way) The only way to test the function of the lambda is to tap the signal wire from it and connect the tap to a voltmeter.