Wall stands at 10-under-par 134 and leads Stephen Gangluff and Kevin Pom Arleau by one shot at El Cid Golf & Country Club.
Gangluff and Pom Arleau both fired 6-under 66s to reach 9-under-par 135. First-round leader Brian Miller managed just a 1-under 71 to fall into a share for fourth place at minus-8 with Josh Habig (66) and Michael Walton (70).
Wall made his first cut in four starts this season -- a far cry from two years ago when he had a streak of making 19 straight cuts snapped.
For the second straight day, Wall had just one bogey in his round -- at the par-4 eighth. He carded six birdies in the round, three on the front nine and three on the back.
Unlike Wall, Gangluff has been making cuts this year -- he hasn't missed one in any of his five starts. He has a pair of top-five finished already.
'I'm looking forward to the weekend,' Gangluff said. 'I've been playing very well and putting myself into contention.'
Sharing seventh place at minus-7 were Tyler Erickson, Brian Flugstad, Wil Collins, Craig Taylor and Jon Turcott.