I hooked up the thermo valve to the electrical connections that plug into it, bypassed the fuel pump relay, and hooked up 10inHG of vacuum to center port of thermo valve. After 16 seconds with key at on position the thermo valve popped and released the vacuum. Thermo valve is good. Moving on to smoke test and gas anaylzer.


Lou

So I finally got around to purchasing and installing an AEM Air Fuel Ratio Gauge. From what I could tell my mixture was lean since it was registering higher than the gauge max of 18. With a warm car I brought the ratio to 13.5 at idle. This morning I went out in hopes that my cold start issue would be gone but to my disappointment I still had that initial issue. (rise to 2000rpm, then after 2 seconds a drop to 800 RPMs, and then the climb back up to 2000 before settling in low at 800rpms after two minutes). After driving the car to warm it up the idle will settle at 950. My question is on WOT the gauge is rising indicating the engine is leaning out at wide open throttle when it should be getting richer. Why would this happen?

Take this with a grain of knowledge salt as my experience is limited to 4 years ownership: I am not sure the 2000/800/2000/950 is materially far from normal. Mine basically does the same pattern but at 1700/800/1700/950. I think that initial rpm drop is simply the fact that the air supplied by the AAR takes several seconds to have its desired affect as the fuel dumped by the CSV burns off. If you want your rpm high point to be slightly lower I believe you can adjust your AAR so that the air opening isn't quite as big at cold start (lots of threads on that process). I think Tony has stated that the normal initial rpm drop should not go below warm idle of 950 so you are very close to "normal". Overall my thought is simply the electrical/heat influenced helpers/regulators (TTV/AAR/WUR) all had designed coordination by the Porsche engineers. Since it's not modern EFI, these components all work but the exact timing across all ambient temperatures at cold start isn't always perfect/consistent. It also seems varies further as the components age.

Maybe a bit more on the WOT afr issue would help. Is it dropping to 12.5 and then rising to 15 while at WOT? or going from 12.5 to 12.8/13.0? If it's not dropping from your 13.5 idle to something lower, then the vacuum assist isn't working so look there. If it is dropping and only rising slightly, not sure it's an issue at all. If it's climbing to 15 at wot, you got an issue.

Like your AFR gauge placement. I find my a bit tough to see down there but overall I like it being out of the way but still usable when I am curious.