"I am not certain that what you are saying is true. On my 144 I converted it to K-Jet from SU's & I initally didn't bother to hook up power to the control pressure regulator(I didn't bother putting on the AAV either) & the car ran fine but guzzled thur a tank of juice in less than 150 miles! I quickly connected power to it. :)"

Paul,

I could well be mistaken, but based my comment on doing Pressure Tests from the Kjet service manual, where with pump relay jumpered, the CPR heater coil should bring Control pressure up to normal (warm running) value in about 2 minutes. And then reading the following from Bentley/Bosch FI manual:

"After a cold start, fuel mixture needs to be cut back in one or two minutes, but the engine block might take 10 minutes to warm up to the point where it affects the bimatal arm in the Control Pressure Regulator. To ensure that the mixture is not enriched for too long, an electric heating coil warms the arm when the ignition is turned on. Warm-up needs are different for each car model, so do not interchange regulators."

That seemed to imply to me that engine heat sort of "took over" (the CPR heating) after 10 minutes or so. In any case, I don't deny that the heaters aren't needed. Just that I assumed their effect would be "matched" by engine heat after a few minutes, and that the rich warm-up mix would be reduced when that happened.

Perhaps on your conversion to Kjet, you had to mount the CPR where it didn't get the expected heat from the block?

One thing I do know for sure is that mis-plugging the CPR heater connecter to the Frequency Valve will give you FULL-rich all the time. (BTDT)
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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.