2000 5.3 Won't Start

cws3rd · December 19, 2020

Hey All,

Have 2000 Tahoe with 5.3 and 225,000 miles. She runs VERY well, is super reliable and idles at 550 smoothly. Noticed trouble when starting before she completely stopped starting a couple of days ago. Had to turn over several times before it would start, and now nothing happens when I turn it over. Acts like it wants to start and almost does, before stuttering off. Acts exactly how a bad fuel pump would before I goes out completely.

I replaced fuel pump last year and the gauge currently shows 58 psi when I turn the key and then 55 psi when trying to start, so this cannot be a fuel problem, right?

I also have already replaced both the crankshaft position sensor AND the coolant temp sensor. Still, no starty. HELP, don't know where to go from here, thanks and Merry Christmas.

Brian715 · December 19, 2020

Is the security light on by chance? Maybe your passlock is not working properly. Only need three things to start. Comptessed Air, fuel, and spark. You are missing at least one. Fuel pressure doesn't automatically mean the injectors are firing. I would start with a cheap inline spark tester. If it has spark, I would move on to a noid light to check for injector pulse. If that passes check compression.

CamGTP · December 19, 2020

If it runs with some brake cleaner down the intake, then it's a fuel problem.

A live data scan tool would be helpful to see what certain sensors are reading. Like the MAF sensor and MAP sensor. A bad MAF can be bypassed by just unplugging it and trying to start it. The MAP sensor needs to read about 100kpa with the key on engine off. It will read less if you live in higher elevations.