Thermotime switch

Hi,

Have an ongoing problem with the tick-over on my 1.6 Gti
Far too fast.

I think that there may be a problem with the thermotime switch.

Have checked the voltage to the cold start valve when the engine is
cranking.
Am told it should show a voltage for about 3 to 8 seconds

Mine is still showing full voltage after 30 seconds.

Bearing in mind a new thermotime switch is a bit over £110 iOS there any way
of bench testing mine before I splash out.

Thanks
 

Hi,
Your idle problem could be the stop on the throttle body, they do get fiddled with. It's on the top and has an adjustment screw with a lock nut, back it off, put a thin piece of paper in the gap and do up the screw until the paper just grabs, remove the paper and tighten the screw a further half turn, the half is from memory but I'm fairly sure it's right.
The cold start valve you can probably get away with disconnecting, if it's on all the time it would slow the idle if anything by making the mixture over rich, I wouldn't fork out £100 for one.

Unplug the connection to the thermo time switch and start the car, if you get the same problem it's not the switch, with this warmer weather I don't think the thermo switch would be firing the 5th injector?

Many thanks
Have adjusted that but problem still exists

Removed the connection to the thermotime switch as suggested and the engine fired up ok

If I restrict the air flow from the auxiliary air valve the engine speed dopes drop noticeably

I think that the problem may be with the 'plumbing'

The engine is a 1.6 prefix EG and according to the engine number manufactured in 1979.

The auxiliary air valve and cold start valve seem to have been connected with somer sort off home-made jury rigged set-up.
I have taken it off

I have attached two photographs

Photograph 2 shows the rubber outlet from the auxiliary air valve (cut off) and the connection to the manifold.

Am I correct in thinking that these two should be connected?

Photograph 1 shows a connection from the manifold and which was connected to the inlet by the cold start valve (photo 1) by way off a home made 'T' piece.

If I am correct that the two parts in photo one connect where does this lot go?

Any help very much appreciated.



 

The 5th injector is normally active on a cold engine, activated via pressure through the Fuel Distributor & WUR... check your connections from the starter motor, powers 5th Injector... check all the connections TTS/5th Inj etc...

'The thermo-time switch limits the injection time of the cold start valve dependent on the engine temperature. The switch is fitted on a location where the engine temperature can be measured correctly.

When the engine is cold the thermo-time switch is closed and therefore the cold start valve injects additional fuel. But when the motor is already warm when starting it the switch is opened - no additional fuel is injected.

In addition to that the maximum injection time is limited. Otherwise the fuel mixture would enrich too much and the engine would be flooded' 

Hi

Thank you for that
Very much appreciated.

Cheers

Photo 2 they should be connected.

Not sure on air hose plumbing as your car as different to mine, try googleing images of mk1 golf engine bays?

This is a 1.8 but I would have thought they are the same.

Brilliant
Thanks

Will fit as per your photo.

Again

Many thanks. A great help.