Cold Start Problems ?

[K9Torro]

Hello everyone,

Ok I have searched and read 87 pages of topics on cold start problems, and would like some thoughts on my situation.

1979 SC engine just rebuilt less than 100 miles ago.

Problem description:

Car starts great when warm or hot.

When cold the car attempts to start " hit's " but dies, this takes place for several minutes, pumping the throttle with key on seems then closing the throttle when turning over seems to make the car " hit " harder and stay running that extra second.

Once the car does start it sounds bogged down until it warms up then it is fine and runs like a top.

Temp outside is 40 degree's.

My Question:

Is it likely the cold start valve that is bad/going bad or

The WUR which is bad,

My reasoning:

In all the reading of the topics on this subject I thought that if the car started at all it was not the cold start valve, but on the other hand I thought that the WUR controlled fuel pressure all the time hot or cold and if this is correct how can it be bad, also once the car starts it seems to run ok so the WUR should be working right ?

Anyhow thoughts please,

Todd

[Paulporsche]

The WUR can go "bad" in different ways. Usually, it just goes out of spec and produces a cold control pressure that is just too high, which results in a mixture that is too lean. You can lower the cold cp by pushing in the plug @ the top of the unit. In your search, you probably saw how you can make this plug easily adjustable. You don't really have to do this because if you tap the plug in while checking the cold cp w/ a fuel pressure gauge, then you can stop when you achieve the desired reading.

[K9Torro]

Paul,

What is your thoughts on a rebuilt WUR I found one for $235 with exchange vs the cheapest new at $425

Todd

[Rex Walter]

K9Torro,

I have seen way too many failure conditions, and I am still not an expert at fixing them. My experience is that if the cold start injector is not working, the car will not fire at all - no stumbling, just cranking. The cold start injector only runs while the starter is engaged, so if it starts, that is working. Stumbling after it starts is usually a sign of being too rich or too lean - which can be a WUR or aux. air (AAV and/or AAR) depending on what system your car has. I had one that was not getting power to the WUR, it would fire and die, fire and die, fire and die - it was running too lean for being cold. Once it warmed up, then it was running too rich, which had the characteristics of dying at stop signs. The RPMs would just drop to zero and it would not continue running. If I would downshift while decelerating it was worse, and just throwing it into neutral and coasting to a stop it was better.

Hope this helps - Rex

[K9Torro]

Can you simply un-bolt and replace the WUR without any type of adjustments being made if I can find a replacement part ?

thanks

Todd