RE: [DML] The great vapor lock controversy -- AGAIN.
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [DML] The great vapor lock controversy -- AGAIN.

Bill said 

> "High pressure liquid pushing from the rear and

> vacuum sucking from the front side should be 

> more than adequate to clear the lines."


Until you have a sharp hydraulic pulse of 45 psi or more, the injectors
won't open, so the injectors aren't going to be any help in clearing the
lines - until the "vaporized barrier" is re-compressed. When the engine
finally does start running, it is often running on only the cylinders that
the vapor barrier was cleared from first - which explains why initial rough
engine operation is also reported as a related symptom. Eventually the vapor
barrier clears from all of the lines and the engine runs smoothly.





From: dmcnews@xxxxxxxxxxxxxxx [mailto:dmcnews@xxxxxxxxxxxxxxx] On Behalf Of
Sent: Thursday, April 17, 2008 12:04 PM
To: dmcnews@xxxxxxxxxxxxxxx
Subject: [DML] The great vapor lock controversy -- AGAIN.


Like you, I thought the reset time for the RPM relay was so short that
it did not trigger the pump while cranking. Elvis Nocita corrected me
on that. 

The timer chip closes the circuit for about .5 seconds. Every time the
distributor rotates, it resets the timer. Let's assume that cranking
speed is 350 RPM. That means the distributor rotates 175 RPM, or
nearly 3 times per second. That's more than enough time to reset the
RPM relay's timer chip for continuous pump activation while cranking.

The fuel system should be receiving 75 PSI or so while cranking.

I don't deny that K-Jet owners have fuel delivery problems, but
whatever is wrong, it isn't vapor lock.

BTW: "Vapor lock" refers to a suction pump's inability to pull fuel
from a remote gas tank. Tank mounted pusher pumps eliminated that
problem. Feel free to look it up.

Remember that K-Jet is a continuous loop system. Whatever vapor is in
the lines should easily be routed back to the tank. Or out the
injectors ahead of the fuel. Even if K-Jet wasn't a continuous system,
don't forget that there's vacuum on the other side of the injectors.
High pressure liquid pushing from the rear and vacuum sucking from the
front side should be more than adequate to clear the lines.

Consider this: My low pressure fuel pump has no check valve. I have no
accumulator. Pull my filter loose and you're lucky to get a drop of
gas out of the lines (not the filter itself, but the lines in & out).
While idle, my fuel lines are chock full of vapors. Yet my little 4-6
PSI pump has no problem pushing them out of the way. If I can clear
the lines at 4-6 PSI, why can't K-Jet owners do so at 75 PSI? And I
don't even have the benefit of a continuous loop system (carburetion
is one way with a float & needle valve to cut of supply into the carb)).

You all are free to call your cars "vapor locked" if you want, but I
think the problems lie elsewhere.

Bill Robertson

>--- In dmcnews@yahoogroups <> .com, "Gary
Hull" <Specialty@...> wrote:
> Bill,
> If your household plumbing was full of air (or steam) how long would
it take
> for you to get a solid stream of high-pressure liquid out of the
faucet if
> you could only turn the electric water well pump on for three to five
> seconds at a time?
> Gary


[Non-text portions of this message have been removed]


To address comments privately to the moderating team, please address:

For more info on the list, tech articles, cars for sale see

To search the archives or view files, log in at! Groups Links

<*> To visit your group on the web, go to:

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    (Yahoo! ID required)

<*> To change settings via email:

<*> To unsubscribe from this group, send an email to:

<*> Your use of Yahoo! Groups is subject to:

Home Back to the Home of PROJECT VIXEN

Copyright 2006  All rights reserved.

Opinions expressed in posts reflect the views of their respective authors.
DMCForum Mailing List Archive  DMCNews Mailing List Archive  DMC-UK Mailing List Archive