Re: [DML] Fuel pressure at the injectors?

["deloreanfl" <ericp@xxxx>]

Hi Walt,

Well "minimal" plate deflection is just that - a slight deflection of 
the pressure plate (hoping to mimic a light throttle increase). What 
happens is a few injectors vibrate and spray, a few do not, one 
dribbles. Pressing the plate further, they all spray just fine.

The Fuel Distributor is in nearly immaculate shape. The Piston is 
clean, smoothly machined and tighly but accurately glides up and down 
through it's motion. 

Again, what the car does:it idles fairly smooth, heavy accelleration 
is quick and smooth, decelleration is steady and smooth. But light, 
part-throttle acceleration and cruising is choppy - the engine bucks, 
and studders. Exhaust smells extremely rich, and backfires once in a 
while on light throttle or cruising. (Never under heavy acceleration.)

I'll probably use your soaking advice as a last resort, because it 
appears so clean and the fact that when I do depress the pressure 
plate moderately to heavily - I get 6, nice, equal sprays - of equal 
volume. (This leads me to believe the system is not clogged). As for 
shimms, it didn't have them ever. However, you may be right on the O-
ring. It may be out of shape and need to be replaced.

John Hervey's suggestion of swapping around the injectors (one's that 
work in positions that didn't work) is so logical - I missed that 
very obvious course! (DUoah!) I'll do that this evening and see what 
it yeilds. That will at least be a sure-fire check of bad injectors.

Thanks all.

Eric
Dunedin, FL
VIN# 5557
ericp@xxxx



--- In dmcnews@xxxx, "Walter Coe" <Whalt@xxxx> wrote:
> > I cannot figure out why, with minimal air-plate
> > deflection, not all of the injectors fire...but deflecting the 
plate
> > further they all fire equally.
> >
> > Bad Injectors? Faulty Fuel Dist.?
> 
> Eric,
> Since no one else has suggesting anything yet, I'll try to take a 
stab at
> it. With no deflection of the air sensor plate, there should be no 
fuel
> flowing from the injectors. So when you say minimal then 
define "minimal"
> and also explain what kind of symptoms you are having with the way 
the
> engine is running. I have heard that shims are used under the 
plunger of
> the fuel distributor for adjustment. If you had shims in there 
before &
> left them out, then perhaps there is now some slack between the air 
sensor
> plate and the response of the fuel distributor. Since you had the
> distributor off, maybe moving the gasket (or is it an O-ring?) 
underneath
> changed the height of the distributor which could have a similar 
effect.
> 
> Another possibility is that you could have gunk in the 
distributor. Maybe
> you should remove the plunger and soak the whole thing in Berrymans 
B12.
> I've never tried anything like this, so maybe someone else can give 
some
> better advice. I do know that fuel distributors are made with a 
high degree
> of precision. If the plunger doesn't fit exactly right and slide 
freely
> then you will have problems. If when playing with the distributor 
you
> managed to drop or scratch the plunger then you really have a 
problem.
> 
> Walt Tampa, FL