I run an auto repair shop in the desert southwest-new mexico. Over the last 2-3 summers on very hot days usually @105F problems with chevy and gmc 1/2 ton pick-ups 5.3L with gdi. 2017 & 2018 models 40K to 60K miles. Towed in or dropped of with complaint of cutting out and stalling on this day only. Previously no problems at all. By the time vehicles get towed in, or sit for an hour--then start & run fine. Codes are for low fuel rail pressure-usually both banks, and low pressure on low side system. Classic signs of vapor lock we used to see back in the day on carb vehicles or EFI with clogged filter or weak pumps with bad ck valve.
I had that problem today with my 2002 Holden VY SS Commodore which is Australian built & is fitted with the Chevy LS1 engine making it the first Holden to be fitted with a returnless fuel system. I came home from work which finishes @ 12 PM on a Friday & got home at a bit after 1 pm after I did my weekly shopping, it was a hot 35-40°C day & my car is parked outside & was in the hot sun. I drove into town which is about a 10 km (6 mile) drive to grab myself a pizza at about 6 pm & the sun was still up,the weather was still hot. Half way to town,the car hiccupped & lost power,I dreaded it was a fuel pressure issue, well,the check engine thing popped up on the dash. My point is that I drove the car home & it performed flawlessly & had more power,the fuel trims checked at good levels as well,I put it down to the fuel rail being hot & boiling the fuel. I did have them max out to 25% on a couple of occasions,it was because the fuel pressure was 40-50 PSI when it nominally should've been 58 PSI so the ECU was trying to compensate for a bad injector spray pattern by increasing the injector pulse width as far as it could. The cause was a bad fuel pressure regulator.
I have a Toyota GAIA that could not start after timing reset, look at fuel pressure PID reading 0, I don't know way to get the fuel pressure come up for a month now, please what is the way out thanks
Vapor locks on a 1951 Ford 239 cubic inch Flathead engine air bubble trapped in fuel line, fuel line diameter too small, put on bigger diameter fuel line, problem solved, or a rubber fuel line, also the fuel line was bent at a really steep radius going to the carburetor and the bubble got trapped in the bend which didn't help matters any,, bigger diameter fuel line or rubber fuel line, problem solved.
