Re: [DML] Hose routing wisdom, please!

["Walter" <Whalt@xxxx>]

Les,

You are right on target about the operation of the thermal vacuum valve.

While you are in there, make sure that the other half of the thermal vacuum
valve is sending a vacuum signal to the distributor advance after the engine
is warmed up.

When you hook the lines back up where they belong, I suggest making sure you
have vacuum where you should. Since the system has been tampered with,
maybe the vacuum advance has been disconnected as well. I have found that
vacuum lines that are left open can suck up enough debris to clog them.
Just connect a vacuum gauge and see what you get. I think a healthy
DeLorean should draw 18mmHg at idle.

I think it is rather odd that the control pressure regulator has a redundant
mechanism for disabling fuel enrichment after warm-up. I would like to know
which system shuts off enrichment first: Is it the thermal vacuum valve or
is it the control pressure regulator's internal heater? It seems that the
Volvo engineers wanted to make real sure that the enrichment didn't last any
longer than absolutely necessary.

Les -- I have timed how long it takes my thermal vacuum valve to warm up
enough to switch. From a totally cold engine in 80 degree weather, it took
about 2 minutes. Since this part of the system was bypassed on your car, I
suppose that it is of little consequence since the control pressure
regulator's internal heater would eventually turn the enrichment off
possibly even before the thermal vacuum valve would get around to it.

Are there any experts out there who know the answer to this?

Walt Tampa, FL