Car stalling AGAIN, Updates- none of them good. Options

[rjames]

Drove around for 30 minutes in 80+ degree weather. All arterial roads, so several stop lights, etc. No problems until I was almost home. Car stalled when I stopped at a light. RPMs just dropped to zero. Was able to start it again with a little difficulty and had to keep my foot on the gas to keep it from stalling out again. Power seemed ok though the rest of the way home (I think). It stalled once again at a stop light a couple of blocks from home and then again when I pulled in the driveway. I let it sit for 30 seconds, started it again and it idled just fine. Rock solid at 1000 RPMs. Pulled it into the garage where it sits now.

Prior to today the car has been running and idling perfectly since I went through the FI parts last year, which included installing a 123 distributor, new CHT sensor, a newly rebuilt mps (calibrated for correct afr on my engine), new vacuum hoses, NOS throttle body, rebuilt injectors, new fuel pump, valve adjustment and timing.

I haven’t checked the AFR since last year, not sure why it would change though.
It’s a ‘75 so the fuel pump is in the front, so I can rule out vapor lock I think.

Anyone have ideas as to why it would be stalling?

[rjames]

Just wanted to dust the cobwebs off of this thread with an update. I installed a new Bowlsby injection harness (work of art!), and so far...so good. I'm probably jinxing things just by posting this. I hate intermittent issues, and given how intermittent this issue was, I won't be confident that the car won't stall on me again for some time.

Two questions remain:

1) If I leave the air temp sensor plugged in (sensor on the plenum), when cold the car runs fine, but when it warms up, the idle hunts like crazy. If I unplug it the idle is steady both when cold and when it's warmed up.

2) I can't get the idle lower than 1100 rpms. This seems to be an issue others have after installing the 123 distributor and happens whether I configure the distributor it for retard or advance. I don't have a vacuum leak, but I did notice something on both my original throttle body and the NOS one I found last year: When the idle screw is all the way in, a fair amount of air is still being pulled from the top of the butterfly. If the adjuster is all the way in, shouldn't it completely (or nearly completely) block any air from getting in?
(borrowed pic)

[BeatNavy]

Just wanted to dust the cobwebs off of this thread with an update. I installed a new Bowlsby injection harness (work of art!), and so far...so good. I'm probably jinxing things just by posting this. I hate intermittent issues, and given how intermittent this issue was, I won't be confident that the car won't stall on me again for some time.

Two questions remain:

1) If I leave the air temp sensor plugged in (sensor on the plenum), when cold the car runs fine, but when it warms up, the idle hunts like crazy. If I unplug it the idle is steady both when cold and when it's warmed up.

2) I can't get the idle lower than 1100 rpms. This seems to be an issue others have after installing the 123 distributor and happens whether I configure the distributor it for retard or advance. I don't have a vacuum leak, but I did notice something on both my original throttle body and the NOS one I found last year: When the idle screw is all the way in, a fair amount of air is still being pulled from the top of the butterfly. If the adjuster is all the way in, shouldn't it completely (or nearly completely) block any air from getting in?
(borrowed pic)

So I'll give you two (IMG:style_emoticons/default/piratenanner.gif) (IMG:style_emoticons/default/piratenanner.gif) and one (IMG:style_emoticons/default/sad.gif) as a partial victory, pending additional info. Hopefully the wiring harness was the ticket. It would make sense. Intermittent issues could easily be caused by a sketchy wiring harness. Fingers crossed.

In terms of your questions: 1) you are lean at idle. Unplugging the air temp sensor is going to somewhat richen your mixture, and the hunting idle was because it was lean.

2) I think that's normal. I'll go see if I can find one of my TB's and compare, but there are several versions of them, so I may not be able to answer that definitively. Yes, with my 2056, D-Jet, 123 Dizzy, using curve "B" I couldn't get the idle below 1100. I kind of got used to it.

Rock on (IMG:style_emoticons/default/aktion035.gif)