[urq] Re. Warm-up regulator questions

Mon Sep 8 09:36:38 PDT 2008

 I can count the number of times a WUR was bad on a CIS turbo on one hand in the last 15 years.? The basic pressure tests L-A did can eliminate it quickly.? Probst book has a good diagram of the different types of WUR if that's your target.? The very first test I do is ck that black/white tank vent valve for a ripped diaphram, then I look at the 3in elbow hose that routes to the underside of the intake for rips, then ck PCV hoses. New vacuum hoses is a must before you go too far into other diagnostics. ? L-A I presume this to be not an 02 sensor car?? I spent a lot of time on the WUphase of the WX, and found that the absolute best performing engines still have a goofy transition to closed loop.? With the lack of 02 circuit, the engine temp signal is critical to the WUphase in CIS.

HTH and my .02

Scott J

-----Original Message-----

From: Brandon Rogers <brogers at terrix.com>

To: 'Louis-Alain Richard' <laraa at sympatico.ca>; 'Ben Swann' <benswann at verizon.net>

Cc: urq at audifans.com; 'Quattro at Audifans. Com' <quattro at audifans.com>

Sent: Mon, 8 Sep 2008 10:41 am

Subject: Re: [urq] Re. Warm-up regulator questions

I would also do a pressure test - make 100% sure you don't have a vacuum

leak.  There are so many little vacuum lines....

Brandon

'84 ur 

-----Original Message-----

From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On Behalf

Of Louis-Alain Richard

Sent: Sunday, September 07, 2008 10:48 PM

To: 'Ben Swann'

Cc: urq at audifans.com; Quattro at Audifans. Com

Subject: [urq] Re. Warm-up regulator questions

Ben and all,

I followed the advices, and ran the fuel pressure tests today. Surprise,

Geraint showed its nose this morning, maybe posting to thousands of listers

has something to do with this ? :-)

Obviously, as many of you said, the WUR on the car is perfect, every

pressure are within specified range. 

- 6 bar system pressure

- 1.5 bar cold control pressure

- 3.6 bar warm control pressure

- 2.4 bar residual pressure after 10 minutes

I also opened the other WUR to check its innards, and they were quite nice,

not much crud in there. 

I also took the opportunity to check the 2 thermo-pneumatic valves (055 131

851C) I have in my parts stock. This is the small black plastic sensor with

2 vacuum nipples that is installed below cyl #5 and controls the

vacuum/boost going to the WUR. (Don't confuse it with the big brown

thermo-time switch that is installed at the back of the head that controls

the cold-start injector). Here Steve and Ben, you are wrong: this

thermo-pneumatic valve is normally open when cold, then shuts when the

engine is hot (around 100C). Now I'll replace the one on the engine now as I

don't know its condition. I doubt it will change anything for my warm-up

problem, though.

But the fact that no vacuum or boost reach the WUR when hot means that this

special and very expensive WUR is only different from a garden variety WUR

for the warm-up phase. And it means that the 2 different diameter ports on

it are there for what Steve B said, like an accelerator pump on a

carburetor. If boost rise suddenly, then one chamber will receive more

pressure before the other one, richening the mixture for a few seconds. 

That leaves me with an air problem, instead of a fuel problem... The

auxiliary air valve is still suspect. I will take a look at a new one to see

if the 3 I have here are dead, or they just need a bit of cleaning and

adjusting. More to come.

Louis-Alain

-----Message d'origine-----

De?: Ben Swann [mailto:benswann at verizon.net] 

The WUR is often one of those things that may or may not need attention and

you won't know until you open it up.? Running fuel pressure tests before

doing that may give a clue as to if it is operation correctly.

I have a few I rebuilt and they did operate in range after that, although

problems I had ended up being related to something else although I did find

some debris in both.? Usually there would be a tiny bit of crud that can be

carefully cleaned out.? I've had a few that required a little 1000 grit

paper to polish off a little rust area on the diaphragm. Disassemble and

reassemble with methodical care.

There are two ports on the UrQ WUR and they can likely be used differently

than the stock application to provide additional enrichment on boost, but I

found that to be unnecessary. I did think it strange how since the two port

counteracted each other that both wer tee'd into the same manifold pressure

port.? What I found in testing is one port I think the one that enleans is

about 3X the force of the one that enrichens, but forget and it may be the

other way around.? So, basically works per design OK when all is operating

normally.? The thermo-time switch/valve opens when warming up - AFAIRC and

puts the warmup circuit operating to enlean.

I'd have to check my notes I scribbled on the factory training printout I

made to see if what I said is backwards, but basically you can take them

apart carefully and see how they work when cleaning - just be methodical.?

If you find rust, things may be beyond a basic cleaning, but may still be

worthwhile to try.

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