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Re: '89 200TQ: control pressure regulator help needed
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
> lic strip which controls the outlet pressure. On your 200Q you should
> 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.
Steve, thank you very much for a quick response. I do have some additional
> If you have a Bentley it will include a copy of the graph showing control
> pressure given a cold engine and measured over ambient temperature.
> this graph shows an acceptable pressure range that increases with
It does it only from +20° to +70°C. Bentley does not go into negative
The trouble is, my car has problem keeping the warm-up idle at negative
I have checked the pressure in accordance to Bentley.
SOB meets the spec, although consistently on it's highest margine:
Fuel pressure (valve on the gage is open, gasoline flows through the gage):
at +20°C = 23psi (1.6 bar)
at +50°C = 51psi (3.4 bar)
System pressure (valve is closed):
at +50°C = 95psi (6.6bar)
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
seems to me that somebody posted a similar problem, that turned out to be a
poor connection between a temperature sensor and it's plug.
> 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.
> can adjust the mixture by varying the control pressure by playing with
> slug ... but be careful ... as you can imagine it is difficult to back the
> slug out once it is pounded in! You may end up needing to take apart the
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?