[DML] Re: startup video

["content22207" <brobertson@xxxxxxxxxxxx>]

Point of order: I wasn't the one agitating for another website.

Odd fire PRV's are somewhat hobbled at idle to begin with. Layering
Lambda over them just makes the situation worse, as you admit("Even
then the motor WILL hunt"). 

US emissions restrictions are driven by gridlocked metropolitan areas
(well, basically only one: Los Angeles). On the open road they are
pretty much meaningless. Can't remember exactly what the idle MPG
equivalent is, but it's in the single digits. 

As the 1970's waned into the 1980's, manufacturers of engines for
domestic consumption were forced to make them jump through hoops they
were never designed for. Dourvin was no exception. You got some truly
Rube Goldberg-ish engineering. Of course performance and drivability
suffered accordingly. 

The good news is: all this engineering was merely grafted on.
Underneath, with the exception of lower compression ratios, the
original designs are still intact. It is incredibly easy to backdate
any turn of the decade engine, still in the bay. Even variable venturi
carbs can be replaced with traditional counterparts.

Remember that DeLoreans tend to be extremely low mileage cars. An
overwhelming number have less than 60-70K on the odometer, and 20-30K
is not uncommon. I'd wager that most owners produce more air pollution
from their lawn mowers and leaf blowers than a de-emissioned PRV would
ever produce.

Bill Robertson
#5939

>--- In dmcnews@xxxxxxxxxxxxxxx, "David Teitelbaum" <jtrealty@...> wrote:
>
> It isn't all that hard to get the motor to run right. All it takes it
> to have ALL of the systems working correctly! All of the cylinders
> have to be balanced within 5% of each other, all of the injectors must
> be clean and matched, NO AIR LEAKS, good ignition wires, and all
> adjustments made correctly. Even then the motor WILL hunt. The hunting
> will vary during the warm-up cycle from no hunting to some hunting.
> Once the motor is warmed up some hunting is normal. If parts don't
> work it is no reason to disconnect a whole system. If one part doesn't
> work it is easier to replace it then to try to monkey around it. After
> 25 years you can expect to have to replace some parts! I have worked
> on many cars that didn't idle right. It takes a lot of persistance and
> digging to undo all of the little things that have been done wrong by
> previous owners and their "mechanics". Once the motor is properly set
> up it will run well for a long time with no "adjustments", hot or
> cold. It should start quickly, settle done in less than a minute, and
> be drivable right away with no hesitation or stumble. Among the things
>  that HAVE to be right are:
> advance, vacuum and mechanical, and initial timing
> Lambda
> cylinder compression within 5%
> all spark plugs gapped as evenly as possible
> cold start valve
> warm-up regulator
> idle motor
> hidden vacuum leaks (idle motor tube "O" ring for instance)
> throttle stop and idle switch settings
> mixture screw and plug
> All of these systems are in the Workshop Manual. We don't need another
> website for them. You must be through and careful to get everything
> "just right". It can take removing the intake manifold to find the
> broken bolt, the missing or out-of-place gasket or "O" ring, etc. All
> of this takes a lot of time. Something most customers don't want to
> pay for if a mechanic or Delorean vendor has to fix it. That's why you
> see so many cars that don't run "right". If you can do it yourself you
> CAN make it "right".
> David Teitelbaum
> vin 10757
>  
> 
> 
> 
> --- In dmcnews@xxxxxxxxxxxxxxx, "content22207" <brobertson@> wrote:
> >
> > In theory, frequency valves don't fluctuate until water temp is up. In
> > practice, they seem to monkey with the lower chambers anyway. Numerous
> > times I've unplugged the frequency valve on a cold engine and had that
> > characteristic idle hunt smooth out. Don't know what fails between
> > theory and practice, but something obviously does.
> > 
> > Regarding CIS -- you're at the mercy of the idle speed motor & control
> > module. Mine stuck closed at a stoplight once. Had to ride the
> > accelerator pedal to crack the throttle plates until I could get home
> > and throw the stupid thing away. 'Twas then that I figured out what
> > the balance screws were for and how to set them.
> > 
> >
>




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