re. I think I found the problem, now what? (WAS: New member with bad problem)

[Ben Swann]

[Today I got the fitting for the new fuel pump and it now fits very well.

I followed the instructions which many suggested.

Removed an injector from the car and put it into a bottle.
Put the car in the "On" position.
Turned on fuel pump manually.
Tried to move the sensor plate up and down.

The plate which moved freely and easily before got VERY stiff. It would
come
up about 2 mm without a problem but then got too stiff for me to lift with
my fingers. At that point I saw the injector activate. The spray pattern
was
like in those STP TV commercials, "this is what a dirty injector looks
like". Ether way, there was fuel coming out of it so that's all I care
about
at this point. Since I have the air box lose right now I put my hand under
the plate to see just how stiff it is. With some pressure I was able to
lift
it. The flow went up a little bit but as the plate got higher (almost to
the
top of its travel) the flow stopped completely. I lowered the plate down
(there was still considerable force pushing it down) and the flow did not
resume. This explains the problems I have been having 100%. The engine
idling more or less ok but once I pushed the gas it would die even if I
would let go soon after. Does it also explain why my pump fired?

Ether way I turned off the car (put the key in the "off" position, the car
was never "running") and tuned off the pump. After waiting about a minute
or
so I felt the sensor plate again. It was a bit softer than before but still
very stiff. I decided to experiment and began to remove the thing on the
front of the fuel distributor (it is referred to by many names, I think its
a pressure controller of some sort) that is held in by 2 flat-head screws
and has a 2-wire harness going to it.

**** Differential Pressure Regulator - again, it is crucial to injector
spray and will effect fuel pressure.
You cleaned the outside, maybe it is time to clean the inside or replace.
 There are one or two brass set screws that can be removed for disassembly
and cleaning - just be careful, clean and methodical, noting haw it comes
apart.  I've sometimes had to do cleaning twice as first time did not work
properly. Leave injectors out unil you see good spray without plate binding
and through full range of plate lift/travel.  If spray is not perfctly
conical, injectors are marginal, but engine should run.  I usually remove
each injector from its line and spray in carb cleaner, then blast it
through with compressed air nozzle(need rubber nozzle for this).  If they
won't give a nice pattern after this, then replace them.   Replace injector
O-rings at this point if you didn't already *****

Fuel came spraying out like never before! The plate became free moving
again... I screwed the gray thing back
on and tried to start the car. It sputtered a few times but did not want to
go...

*** Try remove and clean again.  Also with diff press reg off run fuel pump
for a second to flush out any debris that might be lodged.  BE CAREFUL as
fuel will go everywhere.  This is not any standard practice, but has worked
for me on at least two of these systems. ****
Ok, Huw, others who know this system. Tell me what to do. I will do it. I
*THINK* the problem is with that gray 2-bolt part not controling the
pressure right. There is a 2 wire connection going to it. How do I test it?
What is my problem?

*** RIght, procedure is in BENTLEY,  I'll leave this one for Huw to advise
futher, but per Bently:

DIfferential Pressure Regulator resistance approx: 17.5 - 21.5 ohm

With 15K ohm resistor inserted in thermo-sender connector -> current at
diff pressure reg should be 60-80ma.

A quick test would be to see if you are/are not getting voltage at the
connector and check resistance of regulator.  My bet is it is more likely
to need cleaning than to have actually gone bad, but I have several used
but good on hand if you need one.  ***

Thanks,

Tyson]

Hope that helps..Ben