Hard starting 5.3

2001 c1500 2wd 5.3 at. Starts OK when cold, and starts right up if you re start within a few minutes. otherwise it takes 3 or 4 short cranks to get it going. If you just keep the starter running it never tries to start. I've changed the fuel filter and pressure regulator, no help.52K miles. Any Ideas? Thanks, Brad

2001 c1500 2wd 5.3 at. Starts OK when cold, and starts right up if you re start within a few minutes. otherwise it takes 3 or 4 short cranks to get it going. If you just keep the starter running it never tries to start. I've changed the fuel filter and pressure regulator, no help.52K miles. Any Ideas? Thanks, Brad


Hay bud,check the battery,and the starter wires.
Also theres a good chance the ignition systom may be at fault,check the plugs,wires and coils.,.....Hope this helps.

Brad, my 2000 4 wd with a 5.3 does the same thing, I also changed fuel filter. Have not changed pressure reg yet, was hoping to find an answer in this forum. Mine started acting up at about 75000 mi.
Jack

Fuel pressure may have something to do with your problem. A weak pump may not deliver enough pressure to get you started the first time.
Also, check the throttle body...a coked up throttle body will cause a hard start/low idle/stalling problem with that model engine. Clean the throttle bore with some cleaner and an old tooth brush, then wipe clean.

Just changed wires, (it was time) did not solve warm start problem. I looked at my throttle body 2 weeks ago when installing spacer plate. It looked fine. Now that we've narrowed it down to possible fuel pressure reg or weak fuel pump, whats the best way to diagnose that.
Thanks,
Jack

My '01 Silverado 5.3L began being hard to start about 3 weeks ago with about 55,000 miles on it. I was able to isolate the problem down to losing pressure on the fuel rail after shutdown. I talked to the guys at 2 dealerships and they said 98% of the time it is the fuel pressure regulator being bad and letting the fuel back to the pump. I changed the $90 regulator and it didn't fix the problem. When I talked to the dealership guys again, they acted like they didn't know where to go next and, of course, I would need to bring it in and pay them to troubleshoot it. Meanwhile, I just turn the switch on and off 2-3 times for 4-5 seconds before starting and it starts OK.

I've heard that it may be a faulty check valve in the fuel pump that costs $400 and an additional $150 in labor to change. Do you guys have any experience with this or know a way that I can check it out further myself?

Thanks,
BREW

You will need to install a fuel pressure guage and watch the fuel pressure. When you shut the engine off, the fuel pressure should not drop.
Any noticeable drop in the first 5-10 minutes indicates a problem.

The fuel pressure definitely drops off within 10 minutes. What I want to know is how to confirm it is the fuel pump before going to the expense of changing it to.

Thanks,
BREW

You will have to block off the pressure and return lines to verify if the pump is the problem....luckly for me, GM has a special tool to block off fuel lines to diagnos this problem.
Look at the fuel lines under your truck, I think there is a rubber section of line between the frame and where the lines go up the back of the engine. You can clamp of the lines there to prevent the fuel from bleeding back to the pump.
Dont clamp the lines so tight you smash them, just enough to close them off.

Well my "check engine light" came on today. Since my last post I trailered acouple of bikes from IN to AL and back. Fuel mileage and performance seemed ok but not stellar. I was going to replace the fuel pressure reg before I left but deceided not to. The error code for the ck engine lite indicated a misfire. Apparently I had fuel leaking from my pressure reg into my vaccum lines causeing a rich mixture. On the way to the shop I could feel the misfire at idle. Now the the pressure reg has been replaced it idles much smoother and seems to start good. My question is : Should I be concerned with changing spark plugs due to rich condition? The plugs are original with 79000 on them. I heard their good for 100,000.
Thanks,
Jack

P.S. GM Merlin if I knew where your soon to be shop was, I would have stopped in.