Warm Up Regulator Question

[fireant911]

Symptoms: The car cold starts perfectly. Attempting a hot start after the car has been setting a few minutes the idle goes to ~ 2,000 rpms. After driving for just a couple of minutes the idle comes back to a rock steady 950 rpms. This high hot start idle happened for the first time a week ago and continues now after every hot start. I have read several other folks posts who were apparently experiencing similiar problems and the finger was pointing at a malfunctioning Warm Up Regulator.

My question is this indicative of a faultly Warm Up Regulator that should be replaced or simply a WUR that is out of adjustment and requires the pin be knocked in to correct the fuel pressures? The overall operation of the WUR seems to be quite basic with only two components that can cause problems on the unit - the heating element and foreign material in the metering chamber. New WUR are quite expensive ($355.85) and rebuilt units (with warranty) can be purchased for $179.95 with an exchange. What are the CIS professional's opinions regarding this situation?

[Paulporsche]

Usually a high cold startup idle means that your WUR and AAR/AAV are working right . The AAR should not come into play in a hot start situation, so maybe there is something wrong there.

If you knock the plug on the WUR I think you will lower the control pressure. This usually enables the idle speed to come up to the higher speed as demanded by the AAR, and will only make your symptom worse.

Have you checked your warm control pressure? Have you looked for vacuum leaks? Have you tried disconnecting and plugging the decel valve and line?

Does the engine feel unduly rich or lean? Does it rev to redline freely, or too freely? I am thinking your mixture is off. You may be too lean. Try richening it up 1/8 turn and see what happens.

Can you turn your distributor rotor easily, and does it snap back when you let go? Is the dist itself fixed, and not rotating?

By the way, I'm not a pro...just a guy w/ one of these cars.

You can also try lowering your idle speed and see what happens under the varying conditions.

If you don't have pressure gauges, try the mixture setting first.

Let us know what you do and what works.

[yelcab1]

It is your WUR that is not regulating at cold-warm temp. You really should get a CIS test gauge to verify that and then you can decide to adjust the WUR yourself.