5th Injector and Thermo time switch

Hi,

I have a mk1 golf GTI campaign which has never been a great starter so I thought it about time to resolve the issue. I am not too good on car electrics and so my (very competent) local garage have been looking at it - so the questions have been passed to me.

The 5th injector and the thermo time switch show red and black for live and white and green for earth.

Does the 5th injector live connect to a live ignition supply or is connected into the main fuse board.

Can any one also confirm how the thermo time switch is electrically connected please.

Hopefully somebody will be able to assist as this problem is the last piece of the jigsaw!

Thanks

Nigel
 

The feed to the thermo switch is from the fuse board.

It's all in the Haynes manual… Tells you how to test the thermo time switch and all the wiring diagrams, how to test and how much fuel should come out of the 5th injector, testing the WUR etc……

Bit worrying why your garage is asking you information on wiring when it's should be available to them??

Are you sure they know what they are doing??  

I've just had my cold start valve fail and had to fit a replacement. It's very easy to test.
Engine needs to be fully cold for the 5th injector to work. It's fed from the starter circuit so the 5th injector gets a live feed only when the engine is cranking. The thermo timeswitch is fed off the same wire and is connected directly to earth. The green/white wire is the earth for the 5th injector and this is connected to the thermo timeswitch. 
When the engine is cold you turn the key and crank the engine. Thermo switch and 5th injector are energised and the injector sprays fuel in to help start the cold engine. At the same time the thermo timeswitch is being warmed by the 12v feeding it and after around 10 seconds (depending on temperature) it breaks the earth path to the 5th injector and stops it spraying.
If you have 12v on the 5th injector wires when cranking from cold then the wiring and thermo timeswitch are working so you need to remove the 5th injector to see if it's spraying fuel. 
Mine was the 5th injector failed and A replacement sorted it out.
I have to agree with mark, your competent garage really ought to be able to work this out.

And run away if they ask "where is the ODB2 socket so I can plug my laptop in to tell me what's wrong?"   

mark1gls said

And run away if they ask "where is the ODB2 socket so I can plug my laptop in to tell me what's wrong?"   

I reckon we could find a spare connector under the bonnet and show them that