Warmup Regulator Strange Issue Solved
 

After my 3.0 liter CIS SC sat all winter in the trailer, with - as usual - no special preparations on my part, it didn't want to start. Squirting some ether in got it to cough, and eventually to run. So I went off to a DE. Same drill much of the time getting it started. First session it ran rather rough. After that it got better (perhaps the STP injection cleaner dumped in the fuel tank helped, perhaps not, and it got some fresh fuel, although the old fuel, which I pumped out and then put back in the tank, looked fine). Was running rather lean from the looks of the tail pipe. Plugs, too.

Well, while I suspected the cold start injector, I'd checked that last fall. I did remember the control pressure being a bit high. Hmm, maybe I'll start there. I have a pushbutton switch on the dash which allows me to run the fuel pump without raising the air flow sensor plate, which ought pretty much to prevent fuel from coming out the injectors while all this is tested.

System pressure: 4.7 bar
Control pressure cold: 5 bar
Pump off, SP drops to 1.8 bar, so that part at least is OK.

Hmmm. Not sure how CP could possibly be higher than SP, but that's what I wrote down. Bottom line, there is a problem, and very high CP seems like it could inhibit starting.

So I took the WUR off to see what I could find. First I tried to blow carb cleaner through the WUR intake and outlet openings. Hmm - I can't get air to blow through. I don't know just how much 100 psi or so air from a standard rubber tipped air nozzle gets in, but 30 or 40 psi ought to be a minimum, and it wasn't moving.

So time to take the WUR apart. There seemed to be a bit of corrosion on what I call in the picture the roofing nail part, and in the hole in the diaphragm plate it fits into. I cleaned that up some, and put it back together. I could now blow through. Reinstalled.

http://forums.pelicanparts.com/uploa...1400908128.jpg

System pressure: 5.1 bar
Control pressure cold: 3.5 bar

CP should be less, but progress. So I took the WUR apart and put in a thin washer under the bimetallic spring.

System pressure: 5.1 bar
Control pressure cold: somewhere well <1
CP after pump stopped: 1.7 bar

What the heck?

Put in a thinner washer.

System pressure still 5.1
CP cold: 0.5
CP after pump stopped: ~2 bar.

So the puzzling issue is how could control pressure rise after the pump was turned off? The accumulator couldn't produce more pressure than the pump, the CSV holds no more than system pressure (and, in fact, system pressure is supposed to fall promptly to around 2 bar when the pump stops). Made no sense.

Consultation did not give me any ideas, so back in again. The roofing nail still seemed like it was or could stick, so I got down to it to really clean it, with a whetstone and little files and such. I didn't want to make it loose in its hole, although the hole in the diaphragm holder doesn't have to have any kind of sealing action. And maybe it needs some extra clearance to let air between the plate and the base of the diaphragm out as pressure forces the diaphragm down to increase the flow?

I also found some copper alloy springy door draft stop which was 0.0043" thick, and made a washer out of it to try to get the CP more into range. I didn't want to do the tapping the plug bit, as that seems a bit iffy, and a friend with actual Bosch training said you can only do that a couple of times before the plug gets loose.

SP: 5.1 bar
CP 1bar at 64 degrees F
Small drop in SP when pump stopped.

And it started right up as it should! Success. Yet to do is a more accurate setting of the CO after much moving back and forth of the setting screw without instrumentation.

So what caused this? The WUR is pretty much a sealed unit, but there appeared to be some rust around the heads of the pan head screws which hold the diaphragm plate in place (which seals the diaphragm). I suppose it is possible that water worked its way down the threads of these screws, because the threaded holes they screw into extend right up to the top of the WUR and daylight. So I put some silicone into the tops of those holes just in case.

Another thing I did was to switch from low grade pan head screws to Allen style cap screws. I was several times worried I would not be able to turn the cap screws as the bits had a tendency to gouge the slots, but that will no longer be an issue, though I hope never to have to take this apart again.

Knowing just what CPs you want is a bit of a crap shoot. The specs give a band with a fair tolerance. I'm never sure if ambient is what the WUR is (guess I could have used the IR gun on it), so most of the time I disconnected the heater. No sense worrying about warm temps until it would start properly with a reasonable cold pressure. To top it all off, this 1982 US 3.0 motor I bought in about 1989 may not have the right WUR! It is the Bosch 033 model. The Bosch troubleshooting manual I have says this is for a 2.7, and it should be an 089 or 090 depending n what reference you use. So I kind of fudged my target values.

So that's my saga.

Lesson for others: if you measure wrong control pressure values, don't be afraid to disassemble the upper part of the WUR. The gasket holding the middle to the lower section seemed pretty well stuck on, and there isn't anything I absolutely had to get to which is accessed from that lower chamber, so I didn't pry those two apart. Both chambers hold a vacuum just fine, using the tongue stuck to the pipe after sucking test.

Oh - maybe next time I will figure out how to use large type in text boxes in pictures.

Great info, thanks for sharing.

Interesting observation........
 

Walt,

That's a very good observation you've noticed and many are not even aware of this occurence. The slight pressure build up on the control fuel pressure after you shut off the PF is caused none other than the FA (fuel accumulator). What you are actually reading is the residual fuel pressure (1 - 2 bar) after the FP is shut off and that's normal condition. Since you have a very low control fuel pressure it would build up but in a case where your control fuel pressure is greater than 2 bar, it would fall down. BTW, the WUR-033 is a vacuum assisted type WUR used in '76-'77 CIS while your '82 (USA model) would need a non-vacuum assisted WUR-090.

Did you inspect the micro-mesh screen filter before you disassembled the WUR? Aside from the bi-metallic deflection setting, another cause for a high cold control fuel pressure reading is a clogged micro-mesh screen filter. So what you actually done was cleaned or removed some of the blockage deposited on the screen (filter) resulting to a lower cold control fuel reading.

Instead of disassembling the whole WUR like you did, you could try cleaning the micro screen with a strong solvent like MEK (methyl ethyl ketone). Use only in a well ventilated work area. CAUTION: MEK is a toxic solvent and care should be exercised when using such solvent.

Thanks for sharing your work.

Tony

Tony - what I recall is that the screen I could see was on the outlet side when looking down into the top with both fittings removed. I squirted plenty of brake cleaner (maybe not as strong as MEK, although I've got some of that, sitting unused, in my cabinet) in both sides, and used air pressure on both, to no effect until I took it apart and could apply air pressure from the inside, so to speak.

Is that where the micro mesh screen is?

Micro screen/mesh location.........
 

Walt,

Take a closer look at your WUR. The micro screen/mesh is located at the inlet or intake port of the WUR. This is the fuel line fitting connected from the FD. The other fitting (outlet) without the screen/mesh is for the return line. The main objective of this very fine screen is to filter the fuel going in and prevent clogging the orifice inside the WUR. The very fine screen does a good job of keeping the diaphragm valve orifice free of particles or dirt. But the screen gets clogged and eventually would need some maintenance to keep the fuel flow.

Tony

Mine had troubles too. I pulled it apart and found it to be clean and couldn't see anything out of the ordinary. Not that I knew what to look for, but no rust or dirt. So I gave it a clean anyway and put it back together. Problems gone and haven't thought about it for the last five years until now.

Tony

Screen: The fitting on my car which screws into the WUR, and on whose upper side the line from the fuel distributor attaches, has no screen in it. You can see right through it.

WUR type. I agree that the 033 is not what any book, manual, Jim Williams website, or other reference available to me lists as the final digits of the Bosch part number for this WUR. But it is what came to me with the engine, and there was nothing else about this engine, which I bought from a guy in Seattle and had shipped, sight unseen, to me, to indicate it had suffered some kind of catastrophe which would warrant slapping a six year older WUR on.

The engine has a vacuum line attached to the upper WUR chamber inlet port. The line has some kind of short adapter on the end, which gives that end of the line a larger ID than the main run of the line. This allows it to be held on with a little hose clamp.

Thinking hard (sometimes dangerous) about all this, I believe that once the bimetal strip is fully heated up, it no longer has any effect on control pressure. So as the engine warms, control pressure rises because the bimetal strip moves upward, reducing the downward pressure on the cup on top of the coil springs below it. At a certain point, the bimetal spring no longer touches the cup, and thus has no influence on the short rod which presses upward, via an intermediate piece, on the diaphragm.

So with a warm WUR (the books say it only takes a couple of minutes, which seems about right from my testing warming it up with a separate battery while watching the CP gauge). From this I conclude that heat has no further role in the A/F mixture.

Am I correct that after things are heated up, adjustment of the cold control pressure, by moving the bimetal spring, has no effect on the A/F ratio of a running motor?

And that the only other contribution of the WUR/AKA CPR comes from the diaphragm stuff under the base of the coil springs? Which moves up (CP higher) when the upper chamber pressure is lower (as in deceleration), and down (richer) when it is not (as in WOT)?

These lower parts seem to move freely. I haven't been inclined to take any of that apart.

So what does it matter if I have a WUR stamped for an earlier system, when it has all the parts and connections I see in my service manual and parts diagrams for the '82 frequency valve system?

Put another way, are the inlet and outlet holes in the WUR over the diaphragm any different in these various WUR models? Are things spaced differently? Or is the thin steel diaphragm piece the same, and the circular protrusion under one of the ports, against which the diaphragm presses with more or less force to alter the control pressure, all the same? This has me puzzled, but since the car ran just fine, and on the race track didn't seem to lack power other SCs had, I am not motivated to get a used WUR with the right numbers but of unknown provenance unless I understand why that should matter.

Leaving aside the question of what WUR I should/should not use, and assuming all the other parts are working properly (and, in my case, the frequency valve operating in WOT mode, which I think is also where it operates when there is no A/F sensor signal (which is the case - I've got headers and haven't plugged a sensor), and ignoring the various air bleed gizmos, the A/F is thus controlled throughout the range of operation by the plunger/slit adjustment (the 5mm hex down under that little hole which adjusts the relationship of the air measuring disk and the lever arm which moves the control slit piece up and down)?

Put another way, the WUR ought not to have anything to do with a high speed lean or miss?

I'm going through all the various air lines and attachments to see if somehow they are introducing a bunch of air which skips the measuring plate. I don't think there is a problem here, but who knows. The auxiliary air slide, once I wrestled it off, closes when I hook it up to a battery, so it is still OK, just as it was in '98 after I rebuilt the motor and tested all this stuff conveniently with the engine on a stand.

The earlier cars used a WUR with vacuum connections for acceleration enrichment. The '82 did not have this; vacuum enrichment was handled by an electronic box that controlled the frequency valve. For this to work, you need a functioning O2 sensor.

Also, the cold control pressure was much higher on the later cars and the warm-up phase was shorter.

Effects? Just guessing, really but I'd say that driveability will be worse when cold or partially warmed up and the mixture will be a little off under 1/3 throttle when warm.

JR

Missing CIS component........
 

Walt,

Since your '82 engine is a USA model, it would not have a decel valve like those in the RoW or Euro engines unless someone added one. WUR-033 is a vacuum type assisted WUR and would need a decel valve to function correctly during a cold start. Where is the vacuum hose connected in the throttle body? Below or above the butterfly valve? Keep us posted. Thanks.

Tony

Correction (edit): Instead of decel valve as shown above it was meant to be the thermo valve.

Tony - the vacuum (type) hose from the top air port on the WUR goes to the top of the throttle body, way above the butterfly. And it is not long enough to connect to the lower WUR port, which sticks out the left side.

So maybe all that does is allow filtered air at ambient pressure (or a hair below - venturi effect or slight drop due to twists and curves and raising the sensor plate?) into the upper WUR compartment?

JR - everything I have ever read says that under WOT the frequency valve has no effect, or that it drops to a kind of neutral mode. Among other things, there are microswitches for idle, and also for WOT. I think those are what communicate with the minibrain so it can tell the frequency relay what to tell the frequency valve to do for idle mode or WOT mode. Which it can do with or without a signal from the O2 sensor. The car ran just fine with no O2 sensor for years (if you discount emissions). It's not on the street any more, so I don't feel guilty about track emissions.

The external fuel control components on my engine, other than the microswitches, are 1) the WUR, 2) the Aux Air Slide or Aux Air Regulator, and 3) the Auxiliary Air valve (a small pie plate with two large air hoses on one side, and a vacuum line on the other. Both the AAR and the AAV get their air from a connection on the back of the rubber boot.

The fuel distributor (the Porsche manual calls it the mixture control unit) is Bosch part number
0 438 100 077.

One of the frustrating things with the factory manual is that the pictures tend to be taken of the first generation of anything. So the fuel distributor pictures don't show the cap screws over the differential valve adjuster screws! But all the SC FDs have these, and I think the 2.7s do also, so the pictures are perhaps from the one of a kind 73.5T?

Tony - after perusing my references (Probst, Porsche/Bosch from the 2.7 era, and the factory workshop manual) and going to Jim Williams' on line CIS primer, I now understand a few more things:

The WUR does not have vacuum control attached to the tubular port on its top - the vacuum hose is just a source of filtered clean air to put the upper chamber at atmospheric pressure. The Bosch number is still wrong for the '82 motor.

Removed the Auxiliary Air Regulator (AKA Aux Air Slide) - the thing with the heater connection. It was working just fine as a quick test connecting it to a battery to heat things up showed. No issues there.

I also removed two rather similar dashpot-like pie tins from the right side to the rear of the AAR.

The first seems to be called a lot of things, and misidentified as well, but it is the Decal Valve. It has a vacuum hose on one side, and two different sized tubes to hold hoses on the other. Both of these hoses, as well as the AAR, get air from a fitting on the boot bridging the two halves of the intake stuff. It's other side joins the output tube of the AAR, and plugs into the housing to which the cold start valve is connected. Thus it, like the AAR, can be used to add extra air to the combustion mix, bypassing the throttle.

I see that its function is to slow the drop in RPMs when you yank your foot off the throttle, and it also can prevent the engine from dying when you do this due to excess richness from the very high vacuum. I vacuum tested it, and it works - enough vacuum and it opens internally and allows air to flow.

The third, and rearmost, gizmo on this engine looks a lot like the Decel Valve, except that instead of a vacuum line on its backside, it just has a hole allowing the rear of its diaphragm to be at ambient pressure. However, the name the various authorities give it, including Porsche, is Auxiliary Air Valve. Reading various posts on the subject I see this described by DIYers like me with variety of names, some just wrong because they are Porsche or Bosch's names for other components. Often the AAR is called the AAV, too.

I almost missed it, but fishing around with my hand back there, after a partial engine drop to gain a bit of room, revealed it. I had forgotten about it. Since this is plumbed in parallel with the AAR, I wondered what it does. It is described as being a means to add some air when starting a hot engine, because the extra air function of the AAR is gone for a hot motor - it is closed off.

So how to test it? Sitting in my hand, I can blow or suck through it in either direction. But it seems to have a whitish valve down inside. Williams notes that a vacuum of 506" should close this. However, I could not easily attach my vacuum (a Mityvac) to either port to see. And I don't know if a running engine will always produce at least this much vacuum even at WOT, where manifold air pressure is at its lowest.

Since I started all this chasing a high RPM lean condition (not due to cracked hoses), I decided that the best thing to do was to block one of its lines, which I did.
'
If I shouldn't have done this (I can always just use the accelerator pedal if I want more air on hot start - in fact, my car has the hand throttle since it started life as a '77), not too hard to undo. In order to reattach the AAR and the Decel Valve I had to do my best pretzel act to get the fasteners into their holes and tightened. But somewhere along the way the bracket for the AAV got lost, so it just hangs on its stiff hoses, including the lines which are steel. Doesn't seem to have caused distress for any parts.

So how would one test the AAV? Is it supposed to be open at ambient? Etc.

Also still unanswered is the effect that having the wrong WUR is going to have? As long as I get its cold pressures within bounds, and adjust the fuel distributor plunger to get the A/F ratio I want with a warm engine, and I keep the frequency valve system working (but without an O2 sensor), ought I not to be able to make this motor used for racing, DE, and the odd Autox work fine?

the large round "disk" that looks like another decel valve (DV) is the aux air valve(AAV). its function is to add air when starting, like putting your foot on the gas. once started, it jas no fucntion. this should not be called an AAR as the AAR

the device with the power plug going to it is the aix air regulator (AAR). it is for cold start and cold running only. it keeps the RPM's up after it is started. after about 5 minutes, it does nothing.

i noticed 2 things when i saw your pics. the fuel in and out are wrong. fuel goes into the side port and goes out the center. i saw tony talked about too. that screen needs to be clean

the other was you have an older WUR which you realize.

one other thing, the 77 FD does not have the adjusting screws on the FD.

the lower diaphragm is pulled up all the time except when you go WOT and perhaps a quick drop when you pressure the gas. kind of like an acceleration pump on a carb.

putting the washer in there is not the way to fix it. take it back out, make sure you have power to the WUR and check cold and warm pressures again.
the last i read they were very low

now to your car.
are you running an O2 sensor?
you have a freq valve?

Actually, on an 033 WUR, the vacuum nipple on the top is connected to a source of vacuum below the throttle valve. The nipple on the side is connected above the throttle.

JR

Vacuum enrichment set-up...........
 

Walt,

JR has given you the right information. With your current set-up, you are not utilizing the 'leaning' characteristics of WUR-033. So what is your WCP (warm control pressure) with the current configuration?

I corrected my previous post. If you are not using the OXS/lambda and like to run your engine as a RoW/Euro engine, you need a thermo valve not a decel valve I inadvertently mentioned in my other post. There are several PP members that went this route and uitlized this configuration (WUR-089 plus thermo valve). PM me if you want their names. Keep us posted. Thanks.

Tony

CIS troubleshooting.......
 

Walt,

If you are still skeptical to what I was suggesting, take a look at these WUR's.

http://forums.pelicanparts.com/uploa...1405348650.jpg

I've been working and calibrating these WUR's for PP members. I don't think you have solved your WUR problem because your understanding about its operation is flawed. But your initiative and determination is quite commendable.

Tony

he really does not need the thermo time valve(TTV). i ran my car for years without one.
if he is up north and drives it inthe winter it will help with cold starts and popping or backfiring when cold. just make sure you have a pop off valve. i think the TTV was another bandaide bosch added to fix lean running when cold.

how the 033 WUR is used depends on his setup.

if he has the FV he needs to check fuse 18.

Thanks to all who have weighed in on this and thought about it with me.

First off, here is the top of my WUR.

http://forums.pelicanparts.com/uploa...1405399276.jpg

I don't know what the two other numbers which are not right after the Bosch part number mean, but it sure looks like the final Bosch suffix is 033 here. I don't dispute that 033 is not what is shown as being the right WUR for an '81-83. Absent a better understanding of how the critical part of the WUR - the spring loaded diaphragm valve - differs from one model (other than the very early ones) to another, I am obstinate enough to keep with it, as it has worked just fine in the past. If I had access to Bosch part numbers for all the little components, I might see that the dual springs inside the WUR which set hot running CP were different from model to model. Or the little rod was longer or shorter. Or something other than what the diaphragm, which seems to act only on the thinner inner spring, does.

Every part of this US CIS, with the exception of the WUR, appears to be just what came on a US CIS in '81-83.

http://forums.pelicanparts.com/uploa...1405399475.jpg

I am hampered a bit because the SC little white spec book I have is for '78-'81 (and the Factory manual stops there also), but I think that nothing changed from '81 through '83, so I should be all right.

So I do have the frequency valve, and the stuff which goes with it (other than a hooked up O2 sensor). My researches tell me that when you go to WOT, the switch on the right (passenger side ) of the throttle switches from grounding a terminal in the minibrain (oxs control unit) to grounding a terminal in the control unit acceleration enrichment - or vice versa, but in any case this tells the mini-brain you are at WOT, and that the frequency valve should go to 65% and stay there. Actually, this change seems to happen at maybe half throttle. And there is another micro switch on the left side of the throttle which is closed at idle, and opens when the throttle comes just off of idle.

This stuff works independently of the oxygen sensor. So it seems what you lose by not having that sensor working is part throttle efficiency. Not a big concern for a track car. I had it hooked up when I ran the car on the street. If I could unscrew the plug in the O2 sensor bung I had welded onto my race headers in the collector, I might put one back in. Because, assuming my understanding of how all this works, while the 02 sensor won't help max performance, neither will it hinder it. The switches (and perhaps the two temperature switches?) plus whatever default is set in the minibrain seem to do just fine telling the frequency valve what to do.

I should have checked the interior light fuse last year, when the engine first started acting up, and I would have found the short in the (disconnected because roll cage left no room for interior lights) interior light system, which left the FV system not working. I had noticed the clock stopped working, but put that down to old age, wrongly as it turns out. All this stuff is on fuse 18.

I stand corrected on where the fuel comes into the WUR when looking at it from the bottom. I've had the thing off and apart so often that I could look at my own photos and visualize where things were right side up. And that inlet side is where I see a screen (or a piece of metal pierced with small round holes, which would act like a screen) down in the WUR itself.

As to setting the cold CP, I don't see why shims under the bimetallic arm would not do the same thing as knocking the plug in from the outside. They certainly decreased the CP, and the thicker the shim, the more the decrease (although I could never make a graph correlating shim thickness to CP change). And in the end, I went back to no shim today - I used my IR heat gun to get WUR temperature (electrical connection disconnected), and the 1981 graph in my spec book, and decided that I was only a little rich. Which I don't think is going to harm cold starting.

I think the cause of all this trouble might just have been bad gas, or some crud which got in the tank. I blew gray tinged gas out of the fuel filter when I backflushed it. I've flushed the injectors backward and forward with brake cleaner and then fuel injector cleaner (didn't notice a color tinge there). I've run fuel injector cleaner from the fuel filter through everything (injectors into bottles). My last flush was with BG44K, which seems to be good stuff and NAPA had it behind the counter instead of out there with the many other similar products. And all my fussing with shimming the WUR was time wasted, though I got pretty efficient at pulling it off and apart.

But it forced me to go back through stuff I had read a while ago, and check everything out.

So the mystery is why the 033. The vacuum type line to it has a sort of reducer so the fatter outlet on the WUR can connect with the thinner rubber line. It is hose clamped on, and in my Factory manual I see a picture of what must be the earlier generation (most of the pictures are anyway) which had what the Euro SC circuit diagram calls the temperature valve (for its heater inside?), and you guys are saying is the thermo valve (a vacuum switch) which those engines and some earlier US ones used.

I've got one more thing to check out. At the very end of the fuel pressure regulator assembly, inside the fuel distributor, is a little O ring. I am told that this can go bad, leading to baffling alterations in engine running. I am waiting arrival of a new O ring from a mechanic friend before I pull that assembly out. I had that out just to look at long ago when I rebuilt the motor, so am confident I can deal with it and not drop it on the concrete or have it fly apart. I'm going to have to use my borescope to look into the hole in the FD when the regulator is out, as I have a suspicion that this O ring does not reside on the regulator mechanism, but sits down in this hole and will have to be fished out.

Then it is off to Dynopro to get the AF ratio to some reasonable and known value, to see if it will run smoothly up to 6,500 RPM when fully warm, and to get a dyno chart. I have one from the same motor from 1997 or 8, but I have a much better exhaust than the 1974 now.

And, if crud from somewhere in the fuel delivery system messed things up back at the engine, I may have to drain the fuel, clean the tank (just because it was clean as could be back in 2001 or whenever I had the tank out and open doesn't mean something bad has gotten in there. Actually, early this year I pumped the tank dry with the fuel pump so I could take it out and do some welding in the front compartment. I didn't see any sediment in the bottom of the fuel jug, so I poured it all back in when I was done. That's a fingers crossed thing at this point. I wasn't methodical enough to start up front, and work back when troubleshooting, and system pressure was fine.

Tony, do you have a picture of the top, side, and bottom of what the proper US Lambda WUR for 1982 looks like? I forgot to take a picture of the bottom of my 033, but I know what it looks like.

And if you, or any of the other guys who know a lot more than I do about the ins and outs of the CIS, see flaws in my logic, so to speak (other than being too stubborn just to buy a used WUR with the proper numbers on it), I'm all ears (well, eyes).

the parts in your pic from left to right are the AAR, decel valve and AAV.

are you sure your CIS is an 83?
the chart i have for an 81 shows it had a vacuum operated WUR. (like the 033).

where to begin?
i am not sure of this but with the O2 not connected, the FV defaults to around 65%. so if it is already at 65%, will it change to go richer when needed? i dont think so, but tony may know.

to the WUR.
the 033 is designed to operate at around 2.8bar. then the vacuum holds the diaphragm up raising the control pressure (CP) up to around 3.6bar. so to make the WUR work with your car either the diaphragm is shimmed so it is up (thats what i would do), or the main body has to be pushed down to raise the CP up to spec. this would mess up the cold CP thus the pin for the bimetal spring would have to be pushed in. (or a washer put under it as you did).
your WUR looks good but what stands out is on the right. that brown epoxy is covering the pin that would be pushed in (like putting the washer under the spring) to lower the cold CP. but the epoxy is still intact. if the pin was messed with, the epoxy would be gone.
BTW, your other 3 parts look good too. not all corroded.

maybe the WUR was connected so the vacuum enrichment was working and somehow it got put on the wrong port on the TB.

here is what i would do:
check my warm and cold pressures.
then i would put a dwell meter on the FV and check its frequency at idle then i would jumper the switch to make it think it is WOT and see if the frequency changes.

if the frequency does not change for WOT, i would configure the 033 to operate like it is designed so it richens the mixture at WOT, especially if this a track car.

the other option is to get the O2 sensor working.

here is a link for some CIS help. it also has part numbers you can check.

911 CIS Primer - Index

Some random observations...

Last time you mentioned how your single vacuum hose was hooked up, it sounds like you had it hooked up wrong.

The 033 wasn't used in the US after 1977. It was replaced by the 045 in 1978, the 072 in 1980 and the 090 in 1981. In 1981, they began using the enrichment controller and FV to enrich the fuel mixture for acceleration during warm up, instead of the vacuum.

Without a functioning O2 sensor, with an engine temp under 15C, the duty cycle should be 65% and you should get acceleration enrichment when passing throttle angles of 1 and 15 degrees. Between 15C and 35C, you'll be at 50% under 35 degrees throttle angle and 65% over 35 degrees, with the same acceleration enrichment as before. Above 35C, you'll have the same duty cycles as between 15C and 35C, with no acceleration enrichment.

JR

The engine serial number indicates it is a US 1983 model.

Good point about checking to see if/how FV changes with changes in the microswitches. The idle one is easy, push it up by hand. I'll have to look to see how to jumper the throttle switch.

Per the factory manual, the oxygen control unit gets a signal from one temperature switch, which is closed until 15C (56F). A second switch, which is open hen cold and connects to the control unit acceleration enrichment unit, closes at 35C/88F. One of these is in the right chain housing cover plate. I haven't looked for the other yet, but it must be in the breather cover?

Jim Williams' Primer was one of the first places I looked. However, in his chart showing part numbers for the many components, he uses the Porsche numbers for the WURs. The Bosch parts just have Bosch part numbers on them.

I'm pretty sure I got the engine with the line which looks like a vacuum line attached where it is - up at the top of the throttle body, so no vacuum. I'll check, but I don't think there are any ports down below the butterfly or in the plastic plenum which are plugged and thus don't have lines running to the distributor (two of those) or somewhere else.

If I understand the vacuum system, it works on the inner spring. High vacuum in the upper chamber allows the atmosphere in the lower to push the diaphragm up, and the inner spring pushes up just that much more on the diaphragm, raising the CP. Under the almost negligible vacuum of WOT, this inner spring contributes less, lowering the CP. Without a vacuum connection, it always looks like WOT, and the spring gives its minimum contribution.

I've seen pictures of WURs where a guy made a hole in the round steel cover on the bottom of the WUR. Inside that hole was a large hex for an Allen. I assume that an assembly inside there is threaded so that the inner spring's perch can be moved up or down or otherwise can be adjusted. I didn't want to get into that. That spring could be shimmed if more pressure from it was needed, but that wouldn't help if less CP was desired. I'm banking on the ability of the FV to do that, and of the mixture control screw to do its job, and thus to adjust out any inherent difference in CP between different models of WUR.

When I have used the dwell meter in the past, it has shown expected values as I recall. Though perhaps what I mostly remember is that it was working more than what it showed. I'll have to check my notes from back then.

The dyno and its A/F recording system should tell me if all this stuff is working OK, despite the fact that there is a diaphragm system which is getting no vacuum.