Uneven Injector Output ***Split from PPR Shim Source ***

[Ron]

Thinking about both pressures @ 70 psi
It doesn't make sense with the previous... But just in case, are you 100% sure the return line from your WUR is connected to the FD as with orange below (ie not swapped with small FV line at FD)?
routing.jpg

[MikeWard]

Hey Mike,

I checked out that link and the kit appears to service (or be a cross between?) the old and new PPRs. Too many o-rings for early style and missing one for late, maybe...
(Or maybe I'm missing something ;-)

You'll see what I mean in the pic:

Attachment 59972

That's interesting. I can't say I have ever see the type shown on the left in that picture, and I've shimmed a fair few PPR's over the years, they have always been the type shown on the right. What manual is that diagram from?

The kit is intended for hot start issues, it's not intended to be a PPR rebuild kit which I would assume is the reason that it doesn't come with the third o-ring you identify in the diagram.

EDIT: You do NOT remove the WUR/CPR electrical plug when using the chart at D:02:01 (posted above). ...this applies to D or non-D WUR/CPRs.

I would disagree with the manual in that respect. I was taught to always disconnect it along with the vac pipes, and use a laser thermometer to monitor the casing/pressure and reference against the graph as it warms up naturally.

[bytes311]

Thinking about both pressures @ 70 psi
It doesn't make sense with the previous... But just in case, are you 100% sure the return line from your WUR is connected to the FD as with orange below (ie not swapped with small FV line at FD)?
routing.jpg

That line in particular appears to be connected correctly according to the diagram.
connection.jpg

[Ron]

Dang...That end was chopped off in the other pic and the pressure would act just like what it is doing now.
If you do try dumping the WUR return into a container while the pressures are both high and ~equal and a lot of fuel doesn't come out of the return line, look for foreign material at the WUR ports and inside the PPR. The passage in the FD for the WUR return is very small...just right to allow a piece of an o-ring to push up against the PPR and restrict the fuel flow.
Sounds like trash has came loose and/or the WUR just took a dive...

[bytes311]

Dang...That end was chopped off in the other pic and the pressure would act just like what it is doing now.
If you do try dumping the WUR return into a container while the pressures are both high and ~equal and a lot of fuel doesn't come out of the return line, look for foreign material at the WUR ports and inside the PPR. The passage in the FD for the WUR return is very small...just right to allow a piece of an o-ring to push up against the PPR and restrict the fuel flow.
Sounds like trash has came loose and/or the WUR just took a dive...

Behind the large banjo bolt on the WUR is what appears to be a brass screen/filter. It doesn't look dirty, and I'm able to blow compressed air through it and out the other port. Can this screen be removed to determine whether there is something restricting flow on the inside of it?

[MikeWard]

Behind the large banjo bolt on the WUR is what appears to be a brass screen/filter. It doesn't look dirty, and I'm able to blow compressed air through it and out the other port. Can this screen be removed to determine whether there is something restricting flow on the inside of it?

The CPR should have a fine mesh filter.
CPR_Filter.jpg

Unfortunately (and particularly on American rebuilt units) it is typical to see the original filter swapped out for a sintered style brass filter. I can't say if that restricts/impedes flow, we are fortunate in the UK that we have the legendary Ken Mills Injection who can overhaul CPR and fuel distributors to oem factory spec (as sold via DeLoreanGo). One for the connoisseurs where only the best will do.

There is a high probability of destroying the filter if you try to remove it.

[Ron]

Behind the large banjo bolt on the WUR is what appears to be a brass screen/filter. It doesn't look dirty, and I'm able to blow compressed air through it and out the other port. Can this screen be removed to determine whether there is something restricting flow on the inside of it?

If that screen is blocked, it would act exactly like it is now (pressures always equal). But that is the inlet port -- Trash collects on the external side of the screen... Fuel goes through the screen and a valve then back to the FD port that dumps into the tank. Passing the test in my last post would eliminate the entire assembly WRT blockage.

[Ron]

I finally found an ancient backup CD I misplaced. Below is a pic from a temp directory where I kept things I was working on.

FuelSys_TEMP.jpg
(I can't remember where I got this, who to credit, or how much I butchered it ;-)

[Ron]

That's interesting. I can't say I have ever see the type shown on the left in that picture, and I've shimmed a fair few PPR's over the years, they have always been the type shown on the right. What manual is that diagram from?

The kit is intended for hot start issues, it's not intended to be a PPR rebuild kit which I would assume is the reason that it doesn't come with the third o-ring you identify in the diagram.

Couldn't find where that came from...I'll look more later.
Meanwhile check this out:
"In order to fully seal off the control-pressure circuit with absolute certainty when the engine has been switched off, and at the same time to maintain the pressure in the fuel circuit, the return line of the warm-up regulator is fitted with a check valve. This (push-up) valve is attached to the primary-pressure regulator and is held open during operation by the pressure-regulator plunger. When the engine is switched off and the plunger of the primary-pressure regulator returns to its zero position, the check valve is closed by a spring (Figure 17)."

F2.jpg
(Bosch, "Gasoline Fuel-Injection, System K-Jetronic, Technical Instruction", Pg. 20-21.)

The 3rd o-ring is for the check (push-up) valve and it is all about rest pressure, no?

I would disagree with the manual in that respect. I was taught to always disconnect it along with the vac pipes, and use a laser thermometer to monitor the casing/pressure and reference against the graph as it warms up naturally.

I guess it wouldn't really mater if all you were going to do was check the pressures (as is the case here). But I always left it connected because I've never seen a manual call for its removal (not that that means one doesn't lol), and it would definitely have an effect on the info contained in the following charts for example (because time is involved).

F27.jpg
(...,Pg 27)

[Ron]

Another manual answers both questions:

PlugItIn2.jpg

Probable Causes2.jpg

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I found 4 different types of WUR/CPRs (sorry about poor image):
4PPRs.jpg
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Couldn't find the source for the pic with 2 PPR designs.
FWIW, one says early v/s late happened "about 1980".