911S 2.2 MFI starting problems

[Plavan]

I have a 2.2S motor with MFI and have some questions. This is my first MFI car and have no knowledge of MFI...only webers.
I have screwed (read: messed) with the screw that hits the microswitch to shut off fuel when throttle is released (I think that is what it does... again MFI rookie)
Sometimes when I start the car after running it it will crank over forever then finally one cylinder will fire and slowly start the other cylinders. Almost like the motor is flooded. It did not do this until after I messed with that adjustment screw to lower the idle a bit. I'm talking cranking the motor for almost a minute at times. Any suggestions?
Other times in the morning it will start right up (when not having been run)
1. I don't think it is vapor lock
2. it will also have irratic idle sometimes (fixed by blipping the throttle)
Any suggestions for this MFI rookie would be great. Any ideas on that screw adjustment?
Thanks,

[Plays with cars]

STOP!! Don't turn another screw until you've reviewed the articles at this site: http://www.pelicanparts.com/techarticles/911_MFI/TipMFI.htm. This is a comprehensive collection of MFI articles that will describe how to adjust your injection system properly.

The micro switch should be adjusted so that it clicks on and off just as the throttle is open/closed, but is not a control for idle speed. Adjusting idle speed is a combination of setting the butterfly stops on each injection stack, adjusting the linkage to match, then adjusting the air bleed screws on each stack. Not a simple procedure, and requires a synchronizing gauge like you've probably used on your Webers. But, definitely worth it when it's dialed in properly.

Hope the link helps.

[Plavan]

I hear what you are saying. Now when I read what I wrote, I used a poor choice of words to describe what I was adjusting it for. I adjusted it to click the micro switch when the throttle is released...not for idle. It was not always hitting the button upon throttle release and the throttle would jump up and down. I will read the article for some tips.... Thanks!

[HawgRyder]

I had almost the same problem with mine.
I found that the enrichment solenoid was coming on even though the engine was warm.
The power for that solenoid comes from the "start" position of the ignition switch...then goes through a temperature sensor before it gets to the solenoid.
The only time power is applied is when the starter is cranking.
I bypassed the whole system with mine until I can get the engine out (the temp sender is near the part line of the cases right next to the trans).
You need the enrichment solenoid to start when cold...but not when warm.
Bob

[jluetjen]

Bob;
One of the things that I've learned from reading all of these MFI posts is that our '69 cars are different then the '70's and later because we have temperature solenoids. The later cars do not.

What I've done with mine is wired it into a switch on the dash which I close when the weather is cold and the start circuit is powered up. It enrichens the motor just enough so that it lights right off. I then open the switch (which prevents the solenoid from being powered up) so that the engine will start with out flooding when warm.

[HawgRyder]

Yup...same here John....
Used the back window defrost switch...my back window's heat traces were open anyway...so I tossed the wiring going to them.
Bob