1973 mercedes 450sl

Try disconnecting the connector going to the cold
start injector (next to the idle adjustment), and see if
that stops the smoking.

Steve
"450sl" wrote in message

> my car will run fine until its driven for about 30 minutes then it will
> miss very bad, it seems its getting too much fuel, because it will start
> to smoke black smoke, could this be the switch over valve, vacume advance
> or what. I welcome any suggestions.
>
 >> Stay informed about: 1973 mercedes 450sl 

450sl schrieb:
> my car will run fine until its driven for about 30 minutes then it will
> miss very bad, it seems its getting too much fuel, because it will start
> to smoke black smoke, could this be the switch over valve, vacume advance
> or what. I welcome any suggestions.
>

Sounds like a hole in the vacuum diaphragm inside the cold start
regulator. There is a possible direct connection between fuel pump hose
and intake.

--

Roland Franzius
 >> Stay informed about: 1973 mercedes 450sl 

does it matter that my 450 is electronic fuel injected instead of manual?
Does the start valve also have a vacume diaphram in it? How hard is it to
find and change? Thanks for your input.
 >> Stay informed about: 1973 mercedes 450sl 

450sl schrieb:
> does it matter that my 450 is electronic fuel injected instead of manual?
> Does the start valve also have a vacume diaphram in it? How hard is it to
> find and change? Thanks for your input.
>

The start valve should be sitting on top of the intake manifold. It
works for some seconds only at starting. Unplug its electric connection
and see the difference. Below 10C (40F) the motor will not start at all.

The cold start enrichment controller is an electric and engine heated
vacuum controlled valve working for some 10 minutes. It is sitting
somewhere at the side of the motor block to feel its temperature. It has
electric, vacuum and gas connections. (extrapolations from 110 jetronic
engine)

--

Roland Franzius
 >> Stay informed about: 1973 mercedes 450sl