k-jet cahsing rainbows - next question - auxiliary air valve

Hi all,

So, to get you up to date- dodgy, lumpy start up and doesn't run smoothly until warm.

Checked fuel pressure ( while 'warm' ((WUR still connected))) -fine
Checked fuel injector spray pattern and made sure not leaking.
Changed Cold start valve.
Cleaned out WUR with air line. Still not entirely sure WUR is functioning properly as fuel pressure was not tested while WUR unplugged, hence cold pressure not checked.
Removed and tested auxiliary air valve.

Does anyone know if this is supposed to be an airtight seal when closed (warm). Mine isn't, though pinched pipe after valve while running and revs didn't alter.

Guessing lift pump is ok, as back system fuel pressure is ok.

Going to change fuel filter tomorrow as can't fill tank fully ( seal gone on lift pump maybe ) so often been dragging in the dregs.

Any advice would be greatly appreciated as this has got me foxed.

Sorry, that should be 'I changed Thermotime switch'. I haven't changed the cold start valve but have checked voltage feed and have checked the running time on it.

Heeeelp!

Have you measured mixture on a gas analyser cold & hot? This would point the finger towards a faulty WUR. Or it might just be that you can tweak it so it runs sweetly no matter what the temperature/warmup phase of the engine.

How would I test the mixture when cold? Disconnect the WUR so the car thinks it's still cold?

dubbycabbydoo said

How would I test the mixture when cold? Disconnect the WUR so the car thinks it's still cold?

The same way you'd test it when warm….but when the engine is cold…..

The WUR cannot be bypassed or disconnected because it forms an integral part of the fuel system. If you disconnect the electrical connection, it still warms up due to convection from the engine, just takes a different time to do it - but this doesn't actually prove anything anyway, just alters how it warms up. Cold is still cold and hot is still hot.

I have to give it throttle when it's cold, or it won't run. Won't that make a difference to the reading?

Just raise the idle a little bit so you don't need to do that.

PS. I tested the mixture on an analyser when it was warm and everything was fine.
I will get it tested when cold and then re-post.

Thanks for your input.