Stalling When Clutch Is Pushed In

My engine rebuild is going great. Still have not pushed it to redline but indications thus far are positive. I've had it to 5k a few times and the boost was 7ish. Holding coolant solid. I'm gonna burn through one more tank of gas, change the oil and she'll be ready for some redline flogs. (weather permitting since cold tires are proving very slippery) Forget traction in second but even third is on the verge of holding on. Slight bump or dip in the road and third can get loose.

Anyway, on to my stalling problem. The wideband AF gauge is providing me info to ponder on the stalling problem. Here's what I have noticed and can duplicate it repeatedly. If I'm cruising and the AF is 14.5ish, I can push the clutch in and it doesnt stall. Likewise, if im accelerating moderately and the AF is 13.5ish, I can push the clutch in and it doesnt stall. Now, when I run up through third and let off the gas and let the car decelerate in third, or any gear for that matter, The AF goes richer on the order of 12ish. If I push the clutch in after a period of decelerating when the AF is 12, it stalls. Computer tries to catch it and will sometimes, but usually it will stall.

Not sure what to conclude from this but the AF has something to do with the stalling I suppose.

BTW, my WOT AF is 11.2-11.6 from 4k rpm and up

Everything is hooked up, no trouble codes. I might play with my fuel pressure and see if that affects it. I'm turned up above stock pressure right now. I needed to squeeze a little more out of my injectors at WOT. I know, my 30lb'ers are maxed. Maybe the band aid of higher FP is making it stall.

I'll lower the FP an see if it solves the stalling. But the WOT mixture is important too. What's the leanest you would tolerate at WOT 10psi?

a91what said:

I run 12 afr at 10psi and 24*timing.

No richer than 11.3 and no leaner than 12.4 or you have issues.

Click to expand...

Ok cool. I will drop the FP a few lbs and see if I can find a sweet spot that makes both ends happy

I fixed the stalling problem or so it stands thusfar. I sinned a little to do it. I turned up the throttle stop screw. Yep,first I unhooked the IAC, then turned up the stop until I was idling about 900. Plugged the IAC back in. Now I can slam the clutch down anytime and it doesn't stall. It also fixed other things. Previously, on cold start the idle would seek and it would stall unless you nursed it with the gas pedal. It would steady out on its own after a few minutes. But now it starts cold and idles steady right away. Also, my Vortec crank pulley has an under drive for the accessories. Because of this the charging was a tad low with the idle at 750-800. Now with the idle varies between 900-1000 and it charges good at that speed.

I've been driving it like this for three days and just checked the codes. 100% clean and clear of all trouble codes. I have previously enlarged the mounting holes in the TPS and adjusted the voltage .95. With the throttle stop cranked up a tad now the TPS voltage is 1.1. Again, dont ask me why but no issues and no trouble codes.

Still tweaking things. I dropped the fuel pressure a couple lbs. My WOT AF is now 11.8 on the top end rpms.