hunting idle when cold - Page 4

Phil Payne · 06-12-10, 05:22 PM

Quote:

Originally Posted by Gouldy

what doe the sensor on the back of the head do ?? the one with the brown plug on it??

Cold start valve thermoswitch.

Quote:

Originally Posted by Gouldy

.. as the earth doesnt look great on that one

There isn't an earth on it - it's earthed through the head. One circuit grounds the cold start valve, the other operates a heater inside the thermoswitch.

Gouldy · 06-12-10, 06:40 PM

well one of the wires is being earthed out on the thermo switch for sure, it looks a bodge job too, where should the 3 wires go to from the thermo switch phil???

Gouldy · 08-12-10, 06:03 PM

right phil

as you can see its the plug on the back of the engine (Brown plug)

the wire colours are

Red/Black
Black
Green/White

the Black one has been run to earth, and very badly if i say so myself, as you can see by the pics the others seem to be as they should but im unsure what to do with the black one, any ideas mate??

You can see how the black wire (which then turns to green) is earthed out on the bulkhead

the bodged wire and the other two which seem to be in good condition

am hoping this is the problem as i seem to be getting nowhere with the car lately

are you guys running KV able to see where your wires run to ?

Gouldy · 08-12-10, 10:11 PM

just figured it out, the black wire needs to go on the Starter motor, when its cranking it will work,

i put the black wire on the battery and the cold start injector is working fine

the ISV is still not working though guys, so i still need some help on this

Gouldy · 09-12-10, 01:19 PM

right, i have just stripped the dash apart to try and fix the heater and locate where the ISV wires go ,

the heater problem is one of the flaps is stuck

the ISV wires, i am still none the wiser??? any ideas

i also found two plugs which arent connected to anything, HELP!!

first one

and it goes into this

2nd one

what is this??? does it control the ISV?

uh oh....

and another mod for the day ......

pimpdriver · 09-12-10, 01:46 PM

Where did you get the sticker from?

Gouldy · 09-12-10, 01:52 PM

ebay

Martc · 09-12-10, 02:02 PM

[quote=Gouldy;182034]right, i have just stripped the dash apart to try and fix the heater and locate where the ISV wires go ,

the heater problem is one of the flaps is stuck

the ISV wires, i am still none the wiser??? any ideas

i also found two plugs which arent connected to anything, HELP!!

first one

There are lots of random connectors in an Audi wiring loom that can be there for accessories that your car does not have.

what is this??? does it control the ISV?

Its known as a TCI unit, it controls the electronic ignition.

Gouldy · 09-12-10, 02:47 PM

ok mark, thanks for that, do you know where the wires from the ISV go ? really struggling now

spaarky · 09-12-10, 08:04 PM

good luck with it m8 - are you convinced it's the ISV ? I only ask 'cos I had similar symptoms but for a variety of reasons, so you really need to be sure that you should be getting current to the ISV when you're testing it - my first thought from your initial post was an airleak somewhere; in my case I looked everywhere before realising it was a hole in the brake servo - replaced that & suddenly I had a cracking engine & brakes too. Have you run it in the dark to see if anything is earthing like plug caps etc ? I also had problems (like many people) with the fuel pump relay - invisible dry joints/solder cracks mean you can get dodgy fuel pressure until the engine is warm, so shitty idle. once warm, the relay board expands & the joints get proper contact so the problem then goes away. also, be sure that the electric senders for the CSV & ISV are working fine - not sure specifically how to check these on your motor, but if the sender is knackered, no amount of new wire will fix the leccy feed problem

09-12-10, 01:46 PM	#36
pimpdriver Devon Pastie Muncher Classic Audi Club Member Join Date: Jul 2007 Location: Calne Wiltshire Posts: 7,530	Where did you get the sticker from? __________________ Winter tyres now! Driving the B2 80CL as a daily and LOVING it!!!!

09-12-10, 02:02 PM	#38
Martc Black Coupe Collector Classic Audi Club Member Join Date: Feb 2008 Location: Towcestershiresheer Posts: 2,934	[quote=Gouldy;182034]right, i have just stripped the dash apart to try and fix the heater and locate where the ISV wires go , the heater problem is one of the flaps is stuck the ISV wires, i am still none the wiser??? any ideas i also found two plugs which arent connected to anything, HELP!! first one There are lots of random connectors in an Audi wiring loom that can be there for accessories that your car does not have. what is this??? does it control the ISV? Its known as a TCI unit, it controls the electronic ignition. __________________ 95 UrS6 87 Coupe Quattro

06-12-10, 06:40 PM	#32
Gouldy Senior Member Join Date: Feb 2010 Location: W.Somerset Posts: 1,083	well one of the wires is being earthed out on the thermo switch for sure, it looks a bodge job too, where should the 3 wires go to from the thermo switch phil???

08-12-10, 06:03 PM	#33
Gouldy Senior Member Join Date: Feb 2010 Location: W.Somerset Posts: 1,083	right phil as you can see its the plug on the back of the engine (Brown plug) the wire colours are Red/Black Black Green/White the Black one has been run to earth, and very badly if i say so myself, as you can see by the pics the others seem to be as they should but im unsure what to do with the black one, any ideas mate?? You can see how the black wire (which then turns to green) is earthed out on the bulkhead the bodged wire and the other two which seem to be in good condition am hoping this is the problem as i seem to be getting nowhere with the car lately are you guys running KV able to see where your wires run to ?

08-12-10, 10:11 PM	#34
Gouldy Senior Member Join Date: Feb 2010 Location: W.Somerset Posts: 1,083	just figured it out, the black wire needs to go on the Starter motor, when its cranking it will work, i put the black wire on the battery and the cold start injector is working fine the ISV is still not working though guys, so i still need some help on this

09-12-10, 01:19 PM	#35
Gouldy Senior Member Join Date: Feb 2010 Location: W.Somerset Posts: 1,083	right, i have just stripped the dash apart to try and fix the heater and locate where the ISV wires go , the heater problem is one of the flaps is stuck the ISV wires, i am still none the wiser??? any ideas i also found two plugs which arent connected to anything, HELP!! first one and it goes into this 2nd one what is this??? does it control the ISV? uh oh.... and another mod for the day ......

09-12-10, 01:52 PM	#37
Gouldy Senior Member Join Date: Feb 2010 Location: W.Somerset Posts: 1,083	ebay

09-12-10, 02:47 PM	#39
Gouldy Senior Member Join Date: Feb 2010 Location: W.Somerset Posts: 1,083	ok mark, thanks for that, do you know where the wires from the ISV go ? really struggling now

09-12-10, 08:04 PM	#40
spaarky Grown up member Join Date: Oct 2008 Posts: 124	good luck with it m8 - are you convinced it's the ISV ? I only ask 'cos I had similar symptoms but for a variety of reasons, so you really need to be sure that you should be getting current to the ISV when you're testing it - my first thought from your initial post was an airleak somewhere; in my case I looked everywhere before realising it was a hole in the brake servo - replaced that & suddenly I had a cracking engine & brakes too. Have you run it in the dark to see if anything is earthing like plug caps etc ? I also had problems (like many people) with the fuel pump relay - invisible dry joints/solder cracks mean you can get dodgy fuel pressure until the engine is warm, so shitty idle. once warm, the relay board expands & the joints get proper contact so the problem then goes away. also, be sure that the electric senders for the CSV & ISV are working fine - not sure specifically how to check these on your motor, but if the sender is knackered, no amount of new wire will fix the leccy feed problem