https://www.thirdgen.org/techbb2/sho...hreadid=206488 Is the first thread for reference.

Thanks to everyone for helping me out there.

So now I'm not pinging, the only thing wrong with the engine is that is still stalls at lights. I can't idle in drive w/o stalling after a short period of time(20-40 seconds).

WOT is perfect, I can romp the gas and get to 100MPH w/o any problems at all now that my ignition problems are gone. She's pulling nice and strong, I was actually feeling very good when I hit it today and felt how it accelerated, the engine is making power from off idle to 5000RPM pulling all the way. My only known mechanical problem is that my valvetrain is making a slight "clacky clack" I don't believe that is my problem for stalling, simply a lash issue.

I'm getting worried because I'm quickly running out of reasons why it keeps stalling. First I thought that maybe when the pinging/ignition problems were fixed it would get rid of the stalling. It extended the idle by an extra 10-15 seconds, but did not get rid of the stalling, only helped a little.

I was running 605 Autolite plugs, I switched to AC Delco R42LTS plugs last night as the 42-44 heat range were what everyone running milded built vortec 350s told me works. I was HOPING that since I just asked pep boys for stock L31 truck plugs that those autolites were stock heat range and that my plugs were getting heat soaked at idle. Not the case, the 42s did nothing for my idle. As far as I know, those Autolite 605s I was running are the hotter version. So changing to colder plugs did nothing to response, idle quality, or power. (edit: i gapped them to .040 as compared to the .035 of the autolites)

Every single one of those autolites came out looking PERFECT. No signs of physical wear, only slightly brownish. They only had 300 miles on them, but still that shows they were not getting beat. They were not white, honestly, I could not have hoped for a better looking plug. Which annoys me, because I still have no idea why it just stalls in drive when idling.

Whats left? I have bright blue spark, new plugs, good ignition. Everything to do with the top end is brand new. It will idle normally ( I wont' say smoothly, the XE268H cam has a nice lope to it, not too much, but just enough) after about 10-15 seconds I will lose the consistent idle and it will get rougher. The engine will shake then continue. The idle will continue to get rougher and rougher and the RPM will slowly get lower and lower. Reving and holding the brake doesn't work, it gets boggy and stumbles. Putting it in neutral and revin allows me to prevent stalling, but as soon as I let off the gas to put it back in drive it just stalls. I restart the car, put it back in gear and drive away. I've stalled in the middle of intersections like that at least 30 times the past 2 weeks.

I just makes no sense, nobody I know can understand what it could be. We dont even know what to look for at this point, because other then the idle stalling, it runs PERFECTS. It has great response, good power throughout the RPM range (no dead spots), no pinging.

I'm open to ANY ideas that dont' require the engine to be pulled out and taken apart. My only thoughts are that SOMEHOW I'm having fuel delivery problems but I shouldn't. The stock inline pump is always running and delivering fuel into my mallory 3 port regulator. We've adjusted the floats with the car in park and idling before, and trust me, the fuel pump is doing its job.

The odd part is that if you start the car up and just leave it in park, you can sit there with the engine idling for 5 minutes as you work under the hood. Yet if you put it in gear, drive around, then sit in neutral or drive it will stall. 2 nights ago I sat with the car idling in park in front of my house as I tuned the ignition for 3+ minutes. I then DROVE 1 mile to an empty parking lot (it was midnight) put her in park, and sat for another 5 minutes tuning the ignition more. Driving it around, parking, tuning the ignition timing. After doing that 3-4 times, I drove home, sat in drive at a dead stop in front of my house, guess what, 35 seconds she stalls. Why on earth will it idle all day long in park, but if I come to a light, and throw it in neutral, it will still start to stall on its own. It makes no sense.

Thanks,

Dave

edit: i have 10.7:1 CR sealed power .125 domed pistons, but compression should be a pinging/ignition problem, it shouldn't affect my idle quality right?

 

So....

Did you ever just sit there and let it stall; then take a look inside the carb to see if there was fuel?

 

The sight glasses would show if I was running out correct? The front two are my primaries...so if I was running that bowl would be empty?

 

I let it stall and checked the front sight glass, took it out, no fuel leaked when I took the sight glass out. And I stuck something in there and it seemed pretty dry. There was a little fuel on the bottom but none visible. So I'm running out of fuel?

How? WOT/part throttle its perfect, no fuel problems. Why at idle would my pump just stop delivering? Everyone I know said dropping the fuel can is a major PITA....

Should I adjust my float for the primaries? It just doesn't make sense. The fuel pump runs, I can hear it. How do I know my floats are good? Should I turn the screw in or out to raise the fuel level? Do it while it's running?

Should I be able to see the fuel line in the sight glass, how high in the sigh glass should it be?

It has to be a fuel delivery problem, cause everything else is perfect. My buddy drove it today and got on it, I'm getting agreement this thing is pulling like a 13 second car. I thought it felt good when I hit it from 45 to 100 yesterday, my buddy drove it today and said it felt real strong, 13 second strong. theres no way it can be anything but a fuel problem the way it drives/pulls, but why only at idle? i would think WOT would be my problem.

 

im not too keen on automatics, but could it be something with the transmission, i mean, if the car will idle all day in neutral, but won't idle for more than a minute in drive, maybe there is something wrong with the tranny or the torque converter....

just a thought.

also invest in a fuel pressure gauge.

then put it in drive, and have a buddy out side the car looking at the fuel pressure gauge as the car stalls. if the fuel pressure drops right before it stalls, theres your problem

 

So I have to split my fuel line to my carb? We've unplugged the carb and put a fuel gauge into the line that normally goes into the carb and it reads 7-8PSI....reading the fuel pressure to the carb as it's running....more plumbing.

I'm def starting to think it's a fuel problem, just not understand why since it's an electric pump that should always be running. I could understand if I was having fuel problems at WOT, or under load, but idle should have the lowest fuel demand right?

 

Well if your fuel bowl is dry, that means that the pump stops pumping when the engine is idling. That probably means that it's running on the oil pressure switch, not the relay; and the oil pressure drops too low to keep the pump energized.

Try putting a light in your dash or somewhere like that where you can see it; tie it to the fuel pump supply. Obviously it should be on 100% of the time when the engine is running normally. My bet is that you'll see it go out when you sit idling.

 

How does that work? Basically when we wired my fuel pump up, we just used a voltmeter and kept on putting the key into the "ready" position, when we found a 12v power source that came alive when the key went into the ready position we tied it into it. So your saying I need to find a different power source? So if I wire my pump into a diff source it should fix it? Still don't understand why it will idle all day long in park.

 

Because the oil pressure is higher.

Get a service manual that includes the schematic of the car's wiring, so you can make an intelligent decision as to where to wire the fuel pump to. From your description, it could be wired to almost anything.