Cold Start Issue - WUR, AAR, Cold Start Valve

[Ryan_Cunningham]

I’ve been having cold start issues that have seem to continue to degrade on my 1981 SC.

The car typically will not start when I turn the key without feathering the throttle a bit. If I hold the throttle at 900 RPM for 2.5 minutes I can remove my foot from the peddle and the car will idle at 500 RPM until warm when it idles at 900 after a few minutes of driving. If I try to drive the car prior to those 2.5 minutes then the car stumbles and dies, or at best the RPMs will fall the 100-200 and then recover.

Reviewing the threads here and my service manual it looks like the culprit could be the WUR, Aux Air Regulator, and least likely, the Cold Start Valve.

Any idea which one to start with?

https://youtube.com/shorts/jaCSbTL3Oq0?feature=share

[Funracer]

AAR easiest to check. Pull off the rubber hose after its been sitting overnight. Use a mirror and flashlight to look inside the hole. There is a plate inside that should be about 1/3 of the way open when cold. Looks like partial moon. If its fully closed when cold the car will be hard to start. The plug on top of the AAR carries current that heats the AAR after start. As it warms up (maybe 10 minutes) the plate should close fully.

Check that first and report back.

[Ryan_Cunningham]

Funracer, thank you.

It looks partially open from my perspective.

[boyt911sc]

Ryan,

What are your fuel pressures (CCP, WCP, SP, and residual)? Without knowing your cold control fuel pressure reading, diagnosing your problem would be very difficult. And you would be doing a lot of guess-work troubleshooting. Secondly, I bet my money that you have unmetered air going into your system. Lastly, you don’t need to touch the gas pedal to START fuel injection system. That’s for carburetor motor. Have the gear in NEUTRAL with the handbrake engaged and reach for the ignition switch through the open driver side window. I don’t even get in and sit inside the car.

Tony

[Ryan_Cunningham]

Tony,

I’m aware I shouldn’t have to touch the peddle to start a properly functioning car, but mine is not working as designed.

I’ll get a gauge and check the numbers and report back once I have the numbers.

Any recommendations on a good gauge to purchase?

[boyt911sc]

Look for S&G Tool Model #33800. Moderately priced and very reliable.

Tony

[Ryan_Cunningham]

Purchased. Thank you.