01 V8 LS starting problem

[sgt_in_usaf]

I've joined the ranks of LS owners with a problem

I've been having starting issues for a while. Until recently, it had frequent problems starting. Unless it had been recently running (within a couple of hours), it usually would take several seconds of cranking before it would actually start. Sometimes (usually when I had 1/4 or less of fuel), it would start up no problem. Tried changing the fuel filter, no luck. Took it to Goodyear last week and they said the fuel pressure showed 13psi, so they changed out the pump and it showed 35psi. It started right up when I went to take it home, but now if it sits for more than a few minutes, it takes several seconds to start. Any ideas what could be causing this? I've read that it's possible that it could be the coil packs, but I'm used to GM vehicles without coil packs and know nothing about them and I know it's kind of a pain in the rear to get to them so I thought I'd ask before tearing it apart.

Thanks for any suggestions.

 

[LS4me]

Could be a leaky injector.

 

[sgt_in_usaf]

What's the best way to check that? Is it something really complicated? I have very little experience working on the engine (I stick to oil/coolant changes and the brakes mostly), but do have access to a full shop with all the tools and materials I would need to do just about anything with a car.

 

[LS4me]

What's the best way to check that? Is it something really complicated? I have very little experience working on the engine (I stick to oil/coolant changes and the brakes mostly), but do have access to a full shop with all the tools and materials I would need to do just about anything with a car.

I believe it's something a shop must do. They have to do an injector leak-down test.

 

[joegr]

Check the fuel pressure again. Maybe it was the pressure sensor, and not the pump that caused the low pressure reading. (Fuel pressure on the LS is electronically regulated, if the sensor is wrong, then the pressure will be wrong.)
Another thing to check on gen I is the Idle Air Bypass Valve. It could be gunked up and sticking.

 

[tireman]

IAC valve

I agree with Joegr, check your IAC first. Its so easy, just two bolts. Look inside for carbon buildup, use carb cleaner to clean it out good, the IAC will go bad over time and you will need a new one. It will cause you all kinds of trouble until you fix it.