Faulty Cold Start Valve

Had an issue where the car would not start when cold if the thermotime switch was connected to the CSV.

When disconnected it would start - hot or cold

When connected it would struggle to start when cold. Solution - TTS was changed and all seemed OK.

So, car now starts if cold i.e. left overnight. However, if you drive the car and then park it up for say 1 hr and then come back, really struggles to start. Disconnect the TTS from the CSV and the issue goes away. Car starts on the button when cold or when warm.

Reading through posts this sounds like a leaking CSV - if so what is the best way to test this? If I disconnect the CSV from the housing - is the priming of the pump when you turn on ignition sufficient or should I run the pump on by bridging the fule pump relay?

Any tips appreciated!

theres a test for the csv and the tts in the haynes

need a test bulb

that should help you figure things out

Hi bytor, I'm experiencing the exact same problem and was wondering if infact my 'new' TTS was at fault, so it's with some interest I read your possible diagnosis of a leaking CSV. Did you get to the bottom of the problem?

Did you ever get to the bottom of this issue? I have a similar problem on my mk1. When the engine is cold it is difficult to start from cold. Once warm it starts and idles fine.

the csv should never fire when engine warm, if it does your thermotime switch is faulty. however it depends just how warm the engien actually is! take the 5th injector off and crank it, see if its firing or leaking. check the wiring too, make sure the green/white wire is not earthed anywhere and you have it on the correct pin of the TTS. also make sure its actually a TTS you have in there! I went to diagnose a starting fault on a cabrio and after faffing with it all day, I notieced it actually had a mk2 digifant ecu temp sensor, rather than a TTS. swapped over, and all was well.

another possible cause is leaky fuel injectors, overnight the fuel evaporates away but when warm its still in there leaving csv on floods engine, disconnecting it solves problem.