Ive got a stock 1986 LG4, CCC I recently rebuilt that is giving me two minor problems. First off, it has a dead spot during mild acceleration. Initially it takes off great, but when I get to about half a pedal, I feel a deadspot. Like acceleration stops for a second then picks back up. It does not happen during WOT or aggressive acceleration.

Next problem, not really a problem but, why do I have to hold the pedal down 1/4 of the way to restart it once it's warm? Shouldn't it start with just one pump of the gas pedal?

Everything else is perfect; idle mixture screws are at 4 turns out, the IAB is at 4 turns out from lightly seated, TPS is .48v and increases with throttle movement. Choke and idle settings are dead on, no VAC leaks. Cold idle is at 1200 RPM, warm idle is at 600RPM in gear, kick on Defrost or A/C and it steps up 200 more.

The dead spot is bothersome though. Any ideas?

 

Have you hooked a dwell meter to it since the rebuild? Your symptoms are typical of IAB adjustment being a bit off.

The choke may need adjustment as well.

 

I'll check the dwell again. The procedure is to check it while it's warm and idling in park correct?

The choke opens a little more than others have posted. When it's cold and immediately after first start, the choke opens about 1/4" (1/8"seems to be the norm) then gradually all the way open as it warms. IIRC it had a hard time starting when I set it to 1/8".

 

Check it warm and make sure the needles 'hovering' around 50% (of 30 degrees). As long as the needle is wavering you'll know it's in closed loop. Let me know what you find.

 

Well it seems to have two different readings. When I initially checked it tonight, it was moving back and forth between 34-38. I thought that was odd so I removed the lid to adjust but, by the time I got a screwdriver it settled to 26-30 with the lid off. I replaced the lid and it went back up to 34-38.

So, air cleaner lid on it reads: 34-38
air cleaner lid off it reads: 26-30

Also, my warm idle is set a little higher than I thought, closer to 700-725. It sems to run better and not stall out. Other than the mild dead spot, this motors purring! Thanks for any advice!

 

Try setting it around 30 degrees with the lid on. Doesn't seem far enough out to cause your problem, but maybe. If it doesn't make a diff, check for a vacuum leaks and make sure your base timing is set between 0 and 4 and is advancing correctly.

Shows how much restriction the stock air cleaner is...