MARTINSVILLE, Va. – After ending Busch Pole Qualifying on Saturday as the highest-placed Chevrolet driver, William Byron’s quest for a Martinsville Speedway grandfather clock hit a speed bump during technical inspection Sunday morning.

Byron’s No. 24 Axalta Camaro ZL1 failed pre-race mechanical measurements and, as such, his sixth-place time of 19.481 seconds (97.202 mph) has been disallowed. He’ll start from the tail in the STP 500.

The Charlotte, N.C., native struggled from the word “go” during practice, losing a tire less than two minutes into the opening round on Saturday and smacking the wall with the right side of his machine.

Luckily for Byron, the damage was light enough that his team could make repairs, and the second-year Monster Energy NASCAR Cup Series driver was able to return for final practice, where he ended the 50-minute session 23rd overall. Prior to his issue in first practice, Byron was third-quick in that round.

“It sucks when you show up your third time here and you can’t make laps,” noted Byron. “You don’t expect (the tire) to blow off of turn two. It was good to just get that out of the way and get it out of my mind.”

Byron also noted that he had no prior warning before the car went into the wall.

“Here (at Martinsville), the air pressure is so low. The pressures are building and you feel like you are on flat tires to begin with, so there is nothing out of the ordinary to feel that way,” said Byron. “It was just confusing when the third lap came around. It did the same thing and then it took off. When it cut, it just took off towards the wall.

“All I can say is that (it) was unfortunate.”

Byron’s team thrashed to repair the car, something the driver noted is critical at a track like Martinsville.

“With the way the Martinsville cars are with the center of gravity and the weight in these cars, you want to keep your primary,” he explained. “It was really important that we fixed it, but it wasn’t that bad. We had to replace the splitter, the pan, and some of the right front suspension was a little bent.

“(It was) no big deal. No chassis damage.”

Prior to Sunday morning’s inspection failure, Byron had a smile on his face and believed he and his team had a shot to contend for a top-five finish.

“I am kind of optimistic, but we have had a rough day,” Byron said Saturday night. “These two-day shows are tough … and we started out with a flat right front and hit the wall. Then in second practice we were way behind because we didn’t have enough practice time. The guys made a lot of great changes to get it right going into qualifying.

“We were really struggling over the bumps over both ends really, and getting on the concrete, but we will see what happens. It should be fun.”

Now, Byron’s quest for victory may still be fun, but his road to the front will be a lot longer than it was.

D.J. Kennington’s No. 77 Chevrolet for Spire Motorsports and Jeb Burton’s No. 52 Chevrolet for Rick Ware Racing also failed pre-race inspection on Sunday morning. Kennington’s issue was at the Optical Scanning Station, while Burton’s issue was chassis-related.

Byron, Kennington and Burton will start 34th, 35th and 36th, respectively, after losing their qualifying times.

All other cars passed on their first time through tech Sunday morning and retain their grid positions for the STP 500, including polesitter Joey Logano, who won his fifth-career pole at the Virginia half-mile during time trials on Saturday afternoon.

Sunday’s race is scheduled for a 2 p.m. start time, with live coverage on FOX Sports 1, the Motor Racing Network and SiriusXM NASCAR Radio, channel 90.