b85 Mondial Cab roughoverly rich idle when cold

The car starts fine, but immediately settles down to a lumpy idle --barely running. This continues for approx 5 minutes. Then the engine speed picks up to about 1200 rpm, and it runs fine. A few minutes after that it settles down to a idle speed of about 1000 rpm. It then drives fine---runs up strong, but I can smell a rich mixture --even when fully warm. I pulled the CAT Converter this past weekend, as the P.O. told me he had hogged it out for better performance, and I now have to get the vehicle smogged to complete my registration process. I have a shop fabricating a replacement Cat using a spun SS center-on-center Metallic substrate 3" Magnaflow unit. It is supposed to flow about 590-600 CFM. But before installing it I need to get to the bottom of this overly rich cold-idle problem.I have already purchased a new cold start injector, thermo-time switch, and O2 sensor. Having read some of the previous posts on this subject, I'm hoping I find that the source of the problem is either the switch or a leaking injector.

Any other thoughts or shared experiences are most welcome. I'm chomping at the bit to use the car this summer here in Northern California.

Best regards,

Geoman

[rscapri2600]

My 85 has a similar problem, however it runs fine once it warms up. I've been meaning to figure out what the problem is, assume it is probably the thermo time switch and hope to look and test it when the weather warms up.

Joe Craven - in NorCal too.

[boeing]

Had the same prob on mine and it end up being the cold start valve. Hopefully it will nail your prob.

regards
Steve