'89 200TQ: control pressure regulator help needed

[quk@sievers.com (Phil Payne)]

In message <961217001547_1653350541@emout01.mail.aol.com> I6941tb@aol.com writes:

> In a message dated 96-12-16 19:06:14 EST, you write:
> 
>> The Control Pressure Regulator is a very low tech piece of equipment.  It 
>> consists of a pressure regulating diaphragm valve that has a heated
>> bimetallic strip which controls the outlet pressure.  On your 200Q you
>> should also have some vacuum (actually boost) lines connected to modulate
>> the control pressure as manifold goes above atmospheric.
 
> No, it does not have, although Bentley shows them.

The 1988 MB engine in the ur-quattro also has no vacuum or boost connections 
to the warmup regulator.  WOT enrichment is done by the computer.

> Fuel pressure (valve on the gage is open, gasoline flows through the gage):
> at +20C = 23psi (1.6 bar)
> at +50C = 51psi (3.4 bar)
> 
> System pressure (valve is closed):
> at +50C = 95psi (6.6bar)

Those are pretty good, especially the 3.4 bar, which is the important one.

> So, the control pressure regulator senses the temperature by it's own body (a
> bi-metal strip) and not with a separate dedicated temperature sensor? It

Two ways - its own internal bimetal strips (2 of them) and physical contact 
with the block.

>>  I had occasion to disassemble one of these and found that there is a slug 
>>  in the side of the casting that adjusts the bias on the bimetallic strip.
  
> I'd like to take it apart to see what's inside. Can I reuse the whatever
> gaskets I'll be taking apart or do I need to get them beforehand?

Yup.  It's sealed via a large O-ring recessed into a cutout.  It's basically a
rubber compression seal - you should have no trouble resealing it.  Martin
at BR Motorsport cautions that you should remove the valve from the block 
_before_ detaching the fuel lines - the Allen-head screws that fix it to the
block are overstressed by the torque on the fuel line bolts.  Don't forget 
"clean room" conditions - make sure any petrol you use for rinsing out has been 
filtered.
 
But before you start - have you set up the fuel injection properly from first 
principles, detaching and plugging the breathers, turning off electricals, 
etc.?   

--
 Phil Payne
 phil@sievers.com
 Committee Member, UK Audi [ur-]quattro Owners Club