Too rich to start; where am I going wrong?

[Adam Gravois]

This is a continuation of my coolant temperature sensor replacement adventure. In a nutshell: I had a very weak cold start that appeared when the ambient temp was above 65F. I replaced the CTS, a bunch of hoses and connectors that broke in the process, and the famous ECU/CTS ground terminal (which was fairly oxidized). Now I can't get ignition.

Please, help me figure out where I am going wrong (probably something I'm not even aware of), or tell me if it's time to swallow my pride and get to the shop.

1. I removed the AFM, reset its idle bypass to 0.5 turn above closed. AFM is newish. Took cover off the AFM to have access to tuning wheel. Put AFM back in car where I could turn the wheel.
2. I pulled the cold start valve, since I had replaced its terminal, to verify it still worked. Not only did it squirt fuel, but the engine started right up! Putting a finger over the hole caused a stall. OK, I guess the mix is too rich.
3. First I tried opening the idle bypass more and more but could not get ignition with or without CSV in place. Then I reset the idle bypass to 0.5 turn above close and took a research break.
4. OK, apparently you need to turn the toothed wheel in the AFM clockwise to lean out the mix. Let's try that.
   As the wheel turned tighter and tighter, I still got ignition with the CSV out, no ignition with it in. Finally, as the spring looked almost as tight as it would go, I could get ignition with a smaller vacuum hose removed. Getting there?
5. Then, SPROING. I tightened too far, the AFM spring unwound violently, setting itself completely slack. I panicked, took a breath, then retightened it a little, and was able to get ignition with the CSV out. Time for another research break.
6. I thought, hmm. Maybe I should try to adjust the idle bypass and the sprocket together? Open the idle bypass one turn and tighten the sprocket 10 teeth. Put CSV in. Nada. Same adjustment again, nada. Try removing the CSV: ignition.
7. Well, I figure, maybe I'll let it idle a while and see what happens. As it warms, the revs start to drop. I put my finger over the hole and the idle stabilizes at around 600. That's good, right? I reattach the CSV and observe.
8. Since the revs are low, and I know it was last tuned ten months ago (by pros, not me) with the cruddy ECU/CTS connection, and they intentionally tuned it a little rich for driveability, I figure: Maybe I should tweak the throttle bypass first? The idle is low, after all. So I let it out a few turns, and the revs climb to about 900, where it used to live when it was happy.
9. Now I'm feeling confident. I bust out the VOM and begin the procedure for tuning the AFM. Maybe if I can get that dialed, the start problem will fix itself? The O2 sensor (about a year & 5000 miles old) gives a steady reading of 935mV. OK, I tighten the sprocket 10 teeth. No change. I give it another 10, wait, and another. It drops slowly to 925mV. Hm. Wait to see if it keeps dropping: nope. We're still a long way out from 650mV, but I give it another tightening. And another. I bet you know how this story ends.
10. SPROING.

Ok, so, time for another research break. Clearly, I need to adjust something before the AFM. Is there another rich/lean adjustment I should look at? Is there a procedure for tuning the throttle bypass/idle speed? Like I said, it was running dandy except for the weak cold start before I got involved. :\

[Lenny D.]

I will respectfully suggest that since you live in Austin, bring your car (however you must) to Terry Sayther (look him up, he knows these cars and has a good reputation). You have altered way too much especially as a novice to try to begin at square one. It will be money well spent.

[Adam Gravois]

Yeah... sigh... It definitely has that 'way over my head' feeling. I've just enjoyed so much that feeling of mastery that comes with doing my own repairs...

I've brought the car to Terry's before. They do good work.

[Adam Gravois]

So yep, I definitely needed professional help.

Here's the missing piece of the puzzle: right at the start of this process I munged the timing. Moved the distributor--I had no idea that was an adjustment! Wasn't 'til later, after much reading ("what is this 'timing' that everyone keeps talking about?") that I realized what I had done. D'oh!

After getting the timing back to 22deg I could get the car started normally, but I couldn't get it running well. Off to Terry's we go. Believe it or not, popping the spring on the AFM isn't so good for it. Don't overtighten. A new used AFM and a tuneup later, my car is back on the road. Let's just call it a $400 learning experience.