Non-starting 16V

**Crasher** · 08-03-2013,12:44 AM

Yes it is the Cold Start Valve. It is also used for acceleration snap enrichment. If a car tends to flood with the CSV connected, disconnecting it can affect driving performance. The valve is triggered during cold start by a feed from the starter motor solenoid during cranking only and the duration controlled by a Thermo Time Switch in the side of the cylinder head. On the starter solenoid there is a black wire, disconnecting this will prevent the CSV's starting enrichment function and not affect its acceleration function.

**macmillions** · 08-03-2013,09:46 PM

Great success!

Thanks Crasher, you are a legend. Having left the plugs out overnight and had cranked the engine with the fuel pump relay disconnected to dry the cylinders, I reconnected it all this evening, but disconnected the 5th injector, went to start and BAM! Fires up instantly. Runs perfectly.

I've not taken it out for a drive yet, but you say the driving will be affected? I'm guessing this has confirmed it is this 5th injector at fault? Can these be obtained at VW still, if this is the case?

What would we do without your font of knowledge on this forum?

**macmillions** · 08-03-2013,10:30 PM

Oops, just re-read your post Crasher, is it more likely that the thermotime switch has packed in, as opposed to the CSV?

**Crasher** · 09-03-2013,12:52 AM

The CSV is a slave device, it just does what it is told and that is open or close. If it was permanently open the engine would behave terribly and it opens only when the starter motor is operating or when the vacuum capsule on the air box gives it a momentary trigger so I think it is just a case of the usual over rich starting of a KR. This is controlled by another device which is electrically and engine heated and VW call it the "warm up valve", I know it as the "Control Pressure Regulator". When these fail they have too low a pressure across them when cold and this reduces the height of the metering head plunger and makes the mixture too rich. Combined with the extra fuel from the cold start injector this can easily wet the plugs, especially when the injectors are getting old and no longer have a full fine mist spray, more a series of pencil lines of fuel. To test the CPR requires specialised fuel pressure testing equipment that is connected between the metering head centre fitting and the CPR replacing the hose and the gauge needs a shut off tap in line. This gauge allows the control pressure and the main system pressure to be measured and then it is possible to diagnose the problem IF the mixture being too rich is the issue. New CPR’s are no longer available directly from a VW dealer but they can be obtained exchange from Bosch under the part number F 026 TX2 095 and they can be bought from VW Classic Spares in Germany for around €519 under VW part number 035 133 403 G.

**macmillions** · 09-03-2013,03:19 PM

Thanks Crasher.

What would you suggest I do in the meantime to prevent this from happening in the future? Should I leave the CSV disconnected? I'm thinking that as the car has been sat for so long, the fuel lines are probably crudded up therefore blocking the injectors. So I'm thinking a bottle of Redex to help clear them, along with a long run, then getting the injectors replaced/overhauled before committing to a new CPR?

**Crasher** · 09-03-2013,04:05 PM

The injectors cannot be overhauled, only replaced and they are easy to do as long as the plastic air tubes do not shatter which they often do.

I can't imagine Redex helping, maybe a very powerful injector cleaner such as a full bottle of Red Line SI1 may help but most cures in a bottle are little more than snake oil.

To reduce flooding and still maintain the CSV acceleration enrichment function, disconnect the (two crimped together in one connector) black wires to the starter solenoid at its 15 terminal directly behind the radiator fan. Leaving the two wires together in the terminal (tape it up to prevent shorts) maintains the CSV's connection with the F93 diaphragm (on a bracket on the air box) and F60 idling switch (on the front of the throttle body), which feeds power from fuse 18 (ignition live line 15) when the engine requires an enrichment boost.

On the subject of the switch you can see on the side of the throttle body, make sure this is pressed closed when the throttle is at rest, it turns on the idle stabilising function.

**macmillions** · 08-04-2013,09:24 PM

Quick question,

Is the warm up regulator as fitted to the 8v GTI KJet the same as the one fitted to the 16v?
The same question applies to the thermo time switch.

Thanks!

**Crasher** · 08-04-2013,11:02 PM

The KR Control Pressure Regulator is specific to the KR engine except for a few odd ball Audi 80's and 100's we did not get in the UK.

**macmillions** · 09-04-2013,07:43 PM

Thanks for that!
Only asking as I have seen someone breaking a K-Jet 8v and I was after the control pressure regulator, but if not, then I wont! Is that the same for the thermotime switch too?

**Crasher** · 09-04-2013,11:49 PM

Bugger, forgot the TTS.

These went obsolete from VAG the middle of last year and were around 390 at the time under part number 043 906 163 A and they fit a huge variety of K-Jet engined VAG cars from the mid 70's to the mid 90's.

Mind you, they never seem to go wrong, I can't remember ever replacing one but I think you would really struggle to buy a new one at the moment.