Cold Start prblem - Where do I look first
 

For quite some time now my 81SC has had a problem at start up. It starts quickly, but it idles very rough and wants to stall if I try to drive it. This clears up once it's warm. Outside of that in runs great.

So where to start, Warm up regulator, cold start valve, Thermo-time switch? Any advice would be very appreciated.

I need to get to the bottom of this. It's very embarrassing to sit in this car while everyone in the lot turns around to see what hunk of crap is tripping over itself so badly. Most are very amused to see it's a 911.


Thanks in advance

Jeff C

warmup regulator. it's making the engine run too lean thru it's warmup period. either replace it, or try the adjustment procedure. there's lots of threads you can search for the procedure, which amounts to tapping the recessed pin on top of the unit, down a few thousandths. too much though, and it will run too rich and surge thru warmup. there's another procedure to pull it back up. before you get started, make sure the warm CO adjustment is rich enough. 3-3.5% hot and leave the oxy sensor unplugged forever. except for emiss test.

My mechanic did exactly that about a month ago. It was fine for about two weeks and now it's crap again. This will be the forth time in a year that this regulator would need to be adjusted. Is it simply time to replace or is constant adjustment normal?

Thanks

Jeff C

81 SC

Anyone ...Anyone ....Bueller

Sounds like a bad WUR. Does your mechanic hook up a CIS pressure tester, or does he just whack on the WUR?

One note: If you tap too far on the WUR, you can pull the plug back out using John Walkers method (tapping a hole, etc), or you can open up the WUR and tap the plug back out from the inside.

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Bill Krause
'79 911SC Euro
MY PELICAN GALLERY