Differential Pressure Regulator Checking (WAS: New member with bad problem)

[Tigran Varosyan]

Ok sounds good. My tester is not the 2 leg kind. Those were nearly twice as
much... I can make that out of mine though. I happen to have a valve and a
large T connection. Will have to buy threaded fitting from a store or
something.

Ether way, I will buy a tester and do the ohms test. Never done that before,
not even sure how to test for ohms but I will learn. How do I test the
harness going to the DPR? Maybe the ECU or something is not sending the
right signal to my DPR...

Thanks,

Tyson



-----Original Message-----
From: R Mangas [mailto:porter_dog at hotmail.com]
Sent: Tuesday, November 26, 2002 6:44 PM
To: tigran at tigran.com; quattro at audifans.com
Subject: Differential Pressure Regulator Checking (WAS: New member with
bad problem)





  The resistance of the pressure regulator should be between 17.5 and 21.5
ohms according to the bently manual.  The procedure for checking the various
fuel pressures is pretty involved, and even the basic tests require a
two-legged pressure tester with a valve like the one in the picture.

   You check system pressure hooking the non-valved hose to the test port
(an unused port in the center of the fuel distributor) and and the valved
hose to the supply line to the cold start valve.

   You've got a two-legged tester with a valve, right?

   Disconnect the dpr and open the valve and jump the fuel pump relay.

   System pressure must be between 75-82 psi.  If below check pump delivery
specs, if above disconnect the return line and recheck.  If ok your return
line is plugged, if not 'replace fuel pressure regulator.'

Robert



>From: "Tigran Varosyan" <tigran at tigran.com>
>To: <quattro at audifans.com>
>Subject: I think I found the problem, now what? (WAS: New member with bad
>problem)
>Date: Tue, 26 Nov 2002 13:43:37 -0800
>
>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. 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...
>
>
>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?
>
>Thanks,
>
>Tyson


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