Cutting off fuel flow to injectors (Re: No Fuel to injectors)

["content22207" <brobertson@xxxx>]

If I lean mixture screw far enough, pulled injector does indeed stop
spraying as Volvo people suggest. Of course engine is running (or
dying at that point), so effect could be reduced activation of sensor
plate. Moot point anyway -- as soon as I crack it back open have
minimum necessary fuel injection at selected idle speed (remember: I
hard select with bypass screws).

All this physics is making my head hurt. Read yesterday's post to
science buddy and he claims I'm still not 100% correct -- hose
restriction redirects energy, not adds to it. He claims PSI measures
energy exerted sideways. Velocity measures energy exerted front to
rear. Apparently energy taken away from sideways pressure is added to
frontwards velocity. And I thought these little silver cars WEREN'T
rocket science!

eMail me direct and I'll tell you what he said about below post
(disagrees in principle, but he says system in car too small to make
any measurable difference). Besides, haven't we digressed totally from
original problem? As I recall fellow had short time to get car running
and out of his garage. I like idea of pulling injector loose and
sticking hose in coke bottle to ensure fuel getting that far. My hard
lines are soldered to banjos so I forgot this was an option (that's
why I suggested buying an extra banjo. Sometimes forget I'm the
exception...). In fact, would you even need to remove hose from banjo?
Couldn't you stick entire end in bottle, banjo and all?

Bill Robertson
#5939

>--- In dmcnews@xxxxxxxxxxxxxxx, "David Teitelbaum" <jtrealty@xxxx> wrote:
> In a static situation in a pressurized system the pressure is equal in
> all parts of the system. Under flow conditions restrictions start to
> have importance. For the purposes of the fuel injection system in the
> Delorean you can assume that unless you have a kink in a hose or a
> plugged valve that the pressure you read is the pressure in that part
> of the fuel system. The size of the hose has no effect on the fuel
> pressure once the system has filled and pressurized. The fuel pump has
> EVERYTHING to do with the pressure in the system as well as the
> pressure regulating valves. You are correct that you need a certain
> minimum pressure before you get the injectors to open and start
> spraying. As long as fuel is getting to the injectors there is only 1
> reason they won't spray, not enough presssure. There can be 2 causes
> for not enough pressure, the pump can't make enough pressure and a
> pressure valve is letting the pressure out, back to the fuel tank.
> Messing with the mixture screw will not get the injectors to open at a
> lower pressure and you will just loose that critical adjustment. 
> Start in the gas tank and make sure the fuel pump isn't sucking in
> any air and the pick-up hose isn't kinked. The fuel system is
> hydraulic, not pnuematic so if there is air getting in it won't work.
> David Teitelbaum
> vin 10757 
> 
> 
> --- In dmcnews@xxxxxxxxxxxxxxx, "content22207" <brobertson@xxxx> wrote:
> > You didn't by chance replace the small diameter line from accumulator
> > to filter with something larger? That small diameter line is what
> > creates high fuel pressure, not the pump itself (is not 75 PSI from
> > the tank). Kind of like putting your finger over end of a garden hose.
> > 
> > See Message #32067. Sounds definitely as though you aren't "cracking"
> > the fuel injectors. Need minimum 50-51 PSI to start spraying. If
> > you're SURE everything from fuel distributor forward is factory spec,
> > may need to adjust fuel mixture screw. You may not have touched, but
> > are you sure no one else has? Note fuel mixture is set with car
> > running -- NO VACUUM LEAKS! If you've got an injector out, plug its
> > port in head -- 1/4" vacuum leak otherwise. Make sure line feeding
> > idle speed motor from under fuel distributor is tight -- 3/4" vacuum
> leak.
> > 
> >