Re: '89 200TQ CPR BW

[human <human@nh.ultranet.com>]

-- [ From: human * EMC.Ver #2.5.02 ] --

>>>The car starts fine in any weather, but in the temperatures below  -5°C I
have to keep the foot on the gas pedal until it warms up or the engine
stalls.

How does the control pressure regulator knows the temperature? Does it have
a temperature sensor built into it? Can it be tested? Can it be disassembled
? Once I am at it I would like to increase the system fuel pressure, 'coz my
car runs lean and pings under high boost. Ned told me at the Glen this
summer that I can drive something in with a drift and a hammer. Has anyone
done it? What would be the reference point? Should I screw up here, can it
bre reversed?

Also does control pressure regulator take a temperature reading off one of
the numerous temperature sensors, that my car has? If so, where is it
located? Can it be tested?<<<

Phew!  If yours is like the older cars I drive, it's a small cast block on
the driver's side of the block, about dead center.  Temperature sensing is
by proximity to the block, ie conductivity.  What it does is use gasoline as
a hydraulic fluid to control the pressure at the dist. block.  usually has
two fuel lines, an electrical connector and two vacuum lines.  I believe the
output pressure is supposed to be about 50 psi when cold - even just not
running cold, and drops to about 10 or 15 psi or something when warm. 
Remember this is not the operating pressure - it's just a signal being sent
back to control what goes to the fuel injectors.  To test this you insert
fuel system pressure gauge in the lines and start reading from cold start. 
I've had them go on me - no idle at all with cold engine - even above
freezing.  

You definitely sound like you have an overall mixture problem, eh?  I don't
think the CPR is the culprit, though.  When it's bad it's pretty extreme. 
Check your fuel filter?  Vacuum lines (propane!  it's the right way)?
mixture via duty cycle?  I had a cold (<50 deg F) start problem last winter
until this fall where the car would start and idle fine but would starve
when I took off (I have to pull right onto a highway 100 feet from my door)
at as low as 2500 RPMs.  Replacing almost all the fabric covered vacuum
lines with new, and one of the "breather hose" manifold vacuum lines reduced
this problem *a lot* and so I figured that the CPR might have been getting a
poor source of engine info there.  I never really got to the bottom of it
though.  It wasn't as bad as I remembered after doing this, but then I
drowned the damn thing.  End of control group!

I know this is only 1/2 knowledgable, but maybe it will help a bit.

I have been told about the "make it richer" mod.  There is a "pin" on the
outer face of the CPR which looks like a production flashing which can be
pushed in to richen the mixture.  It's very subtle I gather, you should use
a nut & bolt so it only moves a tiny bit.  the real way to do it, I've heard
, is to take the CPR apart and shim some internal gizmo - doing the same
thing but under more control.  Since I have two CPR's and Erie said he had
monkeyed with the one I'm running right now, when I get an OXS on this thing
I'll be doing some experimenting.

Will report if I ever learn anything about it!
--
Huw Powell

HUMAN Speakers

http://www.thebook.com/human-speakers