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240 Befuddled . . . .

Kjet can be like that. When things go wrong it seems to become very needy. Parts either need cleaning or replacement. A control pressure that high is basically system pressure as you say. So your engine is running too lean all the time. Once you get that blocked cpr sorted out it makes a huge difference in how well your kjet runs.
 
I have had the CPR apart since the last post and did not find anything of significance but upon reassembly I am still getting system pressure.

edited-image_23.png


One strange thing is a little quarter inch piece of what I thought was an O ring was in the CPR input screen. It had a hole and therefore tubing so it had to have been inside something else. Didn't seem like fuel distributor O rings. I have been there also some time ago.

The one thing I have not done is dig out the filter screens on the input. Air blows through just fine so one might think that fuel would pass the other way. The screens are 4 or 5 layers and appear to be held in place by a tiny retaining washer. I suspect that digging out the fine screen mesh may significantly damage it but that may be the next step.

I will try to get it apart again tomorrow and see if there is some bockage there.

It cranks and responds to throttle but 70 psi control pressure is, indeed, going to lean out the air/fuel mixture.

While looking through the youtube videos this afternoon I came across a modification to make the CPR adjustable. Not something that Bosch thought appropriate to leave in the hands of the unwashed but with the right test equipment would permit fine tuning the air/fuel ratio.
 
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Took a few days off for a walk-about across the Bourbon Trail. Picked up some souvenirs. Long time on my bucket list.

Took the CPR apart again and the screens are the only next step. The control pressure is reading the 70psi of the fuel distributor regulator which everyone seems to say is a sure sign of blocked screens. Since the original fuel issue was rust everywhere it seems appropriate to have a go at it even though failure here could be terminal for any potential rebuild.

Everything I see on Youtube says you just pick them out, clean and straightened and reinstall. Any first hand experience?
 
Took a few days off for a walk-about across the Bourbon Trail. Picked up some souvenirs. Long time on my bucket list.

Took the CPR apart again and the screens are the only next step. The control pressure is reading the 70psi of the fuel distributor regulator which everyone seems to say is a sure sign of blocked screens. Since the original fuel issue was rust everywhere it seems appropriate to have a go at it even though failure here could be terminal for any potential rebuild.

Everything I see on Youtube says you just pick them out, clean and straightened and reinstall. Any first hand experience?

I have got to clean screens in the past. Takes surprisingly little ick to raise control pressure.
 
The day when I had my first 240 turbo repaired by replacing the plugged control regulator was a great day. It ran so much better in all conditions and it had a big chunk of power back.
 
Dear Diary,

I may have killed my WUR today.

With the unit disassembled on the bench I was able to force brake cleaner through the screens both ways. It leaked slowly inlet to regulator nozzle and I was able to squirt brake cleaner through from the nozzle side out with some force.

That had to mean that the thing was clean enough to pass gas but no such luck. Upon reinstalling the gauge was reading the 70psi system pressure. Took it off for the fourth time.

After debating with my self over some of my souvenir bourbon from the trip I got the pick out and dug out the screens. No saving them as they were firmly clamped into place. After carefully cleaning out all the trash that I could see, blowing with air gun and brake cleaner put it back together and back on.

Started right up with 22psi control pressure. I didn't wait until it went through the warm up routine. That would seem to be a clear indication that clogged screens was the issue.

Now I have to wonder if there is enough trash left in the system to foul up the regulation shortly. Failure symptom is running lean but it does run.

I am going to explore obtaining a bench rebuilt and tested WRU but initial searches put that as unlikely or expensive. A review of the rebuild kits determined that the only thing in the $50 kits of any value is the regulation disk. None supplied the nozzle or the filter screens.

Anyway, I think it will regulate through warmup and run now.

Gotta dig the footings for my Scout Camp restrooms tomorrow. Not latrines, real flush restrooms with showers.

Later.
 
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Wheeler Dealers did a redo of a old MB that had injection problems. Mike we to a place in LA that had everything he needed on the shelf.
 
Found a company in Texas that rebuilds the WUR for under $200. Bosch does not appear to sell the critical parts outside their internal rebuild services. Wonder what the situation is with replacing the screens.

DeLorean Auto Parts - https://www.deloreanautoparts.com/warm-up-regulators.html

Guess I will spend time verifying the operation of my modified WUR and have these guys as a back up. Perhaps a call to discuss the situation is appropriate.
 
Have you thought about ordering NOS from the new Delorean Motor Company? They bought all of the NOS parts stock and plan to build new ones soon.
Pretty sure that they aren't coming with K-Jet PRV's though.
Steve
 
You can also try 928 Classics. They are a Porche group but rebuild and bench test the WUR.
 
The only useful parts in one of the many 'kits' I have seen is the diaphragm and perhaps the 'O' ring around the nozzle. The rest is BS.

I will be going down to the garage shortly to run the car through the warm up cycle to see if I have it professionally rebuilt or not.
 
Technical update

Starting from cold (65 F) my lab quality $5 fuel pressure gauge reads 22psi quickly warmed up electrically to 48psi. After the heater kicked out pressure drifted down to 43psi where it remained.

Here is the pressure graft for the 0 438 140 066 WUR.

Warmup-066-specs.jpg


Those readings are sorta/kinda within the grey bar on the graph.

I think that that confirms that the failure was due to a clogged filter on the WUR input.

While the K-jet fuel system may be a step up from a carburetor system it is not at all as precise as modern O2 sensor feedback fuel management. The WUR handles the low temp/choke rich environment for starting and the O2 sensor and frequency valve manages the air/fuel ratio at operating temperature.

Awaiting discussion with WUR rebuilder.

Thanks for the comments along the way.
 
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The only useful parts in one of the many 'kits' I have seen is the diaphragm and perhaps the 'O' ring around the nozzle. The rest is BS.

I will be going down to the garage shortly to run the car through the warm up cycle to see if I have it professionally rebuilt or not.

Check that site carefully. They also have really detailed step by step rebuild manuals with pictures. I am sure if the parts does not come in a kit, they can get it for you.
 
Have you thought about ordering NOS from the new Delorean Motor Company? Steve

Indeed! They have them in stock, or at least they list a WUR but do not describe it as the 066 version so I will have to contact them to verify. They also do not list it as rebuilt which at about $250 shipped it must be. Their core deposit return is very restrictive. If you do not return EXACTLY the unit purchased you don't get the $250 deposit back.
 
Bosch CIS rebuild sources

Well, that was a very nice conversation with John Hervey of DeLorean Auto Parts.

He said that if the control pressure matches the graft specifications and mine does that he wouldn't recommend rebuilding the unit. On the now missing filter screen he advises that he removes them and replaces with a porous bronze filter that just drops into the connector.

One is en-route!

Anyone with Bosch CIS fuel distributor, WUR or frequency valve issues should keep his contact information.

What a beautiful day! And I got the restroom footings completed.
 
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No one should ever create a spreadsheet accounting for restoration expenses.

My version of the sage counsel above -- no good ever comes from adding up everything you have in the car. Plausible deniability.

As expected Tom -- you get to the bottom of things. Mechanically and philosophically.
 
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