MFI: cleaned t-stat - runs worse
 

Hi all,
Last weekend I cleaned the gunk out of my MFI thermostat. When I reinstalled it, the car was difficult to start (the cold start solenoid is not connected) and even harder to keep running. When I gave it more gas, it would die. After a few minutes of restarting, it started to get better. It would finally idle good, but still sputtered and/or died out when I gave it some gas. Eventually, I let it idle for awhile and as it warmed up, it ran pretty well. I took it for a short drive around the block and it seemed ok, but still worse than it was before. I haven't had alot of time to look into it yet, in fact, I haven't tried to start it since then. I was just wondering if any of you MFI gurus had some words of advice for me before I start digging into it.

Thanks

That's because the thermostat is now finally working properly and leaning the mixture out all the way. Someone likely had adjusted the mixture in the past to compensate for the sluggish t-stat that was keeping it too rich.

Now that it's working properly, you need to richen the mixture. Turn the main rack one click counter-clockwise at a time until the car runs well at around 3000 rpm cruising in 2nd or 3rd gear and doesn't buck or lean surge.

Yep, just like Tyson said, but don't adjust more than a few clicks at a time and not when the engine is running. Also there's some good technical resources here regarding this topic and you may want to get a copy of the Check, Measure and Adjust Manual. Better yet, If you have someone who is familiar with the system and can adjust it using a dynometer to set the CO level, that would be optimal. To do it correctly the level needs to be checked under load.