2.0 16v 1994

[jaselp]

can anyone help with my cold running problem. My car has a really bad flat spot when cold and will only rev if i give it full throttle. It feels as if it has stalled and only goes when i give it full throttle but it seems to surge.

[Crasher]

That car has some limited diagnostics so a fault code read is a good idea and I would recommend you change the coolant temperature sender. If your engine is an ABK, this is on the head water outlet between plugs three and four, is blue and held in with a metal clip. ONLY REMOVE this sensor on a cold engine and release the coolant tank cap first. The sensor for the ABK is VAG part number 025 906 041 A and these cost about £15 from Audi dealers. Buy a new O ring as well, part number N 903 168 02 which is about £1.

[jaselp]

my engine is a "ace"

[evokid]

Try cleaning the ICV valve too? Maybe dirt build up. This i believe is cylindrical unit with hose and plug on it , on top of cylinder block somewhere. Think the ACE's have these?
I had a similar thing which turned out to be spark plug leads breaking down when cold!!!

[jaselp]

i've fitted new plug leads, makes no difference.but i will try icv

[scotty33]

Hi

On the ACE the ECU coolant Temp sender is next to the distributor on the rear of the head. If this is failed in such a way that the ECU 'sees' a warm engine you will not be getting any cold enrichment.

[jaselp]

is their a way of testing this?

[Crasher]

As I said, a fault code read is a start for checking what is wrong with your car and you may get fault code

“00522 Coolant temperature sender -G62”

“Open circuit/short to positive”

or

“Open circuit/short to earth”

The coolant temperature sender for an ACE engine is white and brass, it is VAG part number 026 906 161. There is a live data output in Measuring Blocks 000 Zone 1 which is pretty meaningless as the reading goes from 56 to 39 corresponding to a temperate of + 85 ... 100 ° C or you can measure the resistance of the sensor whilst monitoring the engines temperature using a separate gauge and compare this to the graph or rig up a water heating system and temperature readout and measure the sensors resistance and compare it against the graph. If like me you would lose the will to live doing this, you can just fit a new sensor for about £25 and see if it cures it.