Intermittent starting and not starting

[Dan h]

I have a 98 k1500 Silverado with the 5.7L. I have changed the fuel pump, fuel filter, and fuel relay and still get intermittent times when it doesn’t want to start. It cranks like it wants to start but won’t. What else could be causing this

 

[Pinger]

I have this too on my 1999 C2500. PassLock is suspected. Not sure if it was introduced by 1998. Others more knowledgeable will advise.

 

[someotherguy]

98 is first year for Passlock but don't assume it's a Passlock issue. Passlock will allow the engine to start but then immediately shut it down.

Typical cause for a small block Vortec to intermittently not want to start would be marginal fuel pressure. Time to get the gauge on it and see what it's doing. If it's not a solid 58-62 psi then that's an issue for the small block, at least with the original poppet valve injector setup. Below 58 psi is not enough to reliably open the poppets.

Richard

 

[HotWheelsBurban]

I have a 98 k1500 Silverado with the 5.7L. I have changed the fuel pump, fuel filter, and fuel relay and still get intermittent times when it doesn’t want to start. It cranks like it wants to start but won’t. What else could be causing this

Have you changed the crankshaft position sensor? They do go out gradually and they can cause this problem. Passlock will allow the engine to crank fine, but it will shut off the fuel in 2 seconds if the system activates. Had a lot of fun with this last summer....
Check fuel pressure, also how good are your distributor cap and rotor? Bad rotor can also cause a start and run issue. But my first suspects are fuel pressure and crankshaft position sensor. Also check battery, cables and grounds and connections. Good luck and post up what finally fixes it

 

[Pinger]

CPS usually only a problem when hot - stalling at junctions a typical symptom and having to wait 20 mins for it to restart (after its cooled). Could be different with these trucks though.....

A smell of fuel at the exhaust (or a wet pulled spark plug) would point to ignition problem.

 

[willc]

Dan,

When you changed your fuel pump, did the new pump kit come with a new pigtail connector for the wiring harness side? I have a 1998 tahoe and many years ago the fuel pump connector went bad intermittently. Sometimes the truck would not start. Wait some time and it would start. I finally narrowed it down to the connector and changed it out. Problem solved. A few years later I changed the fuel pump and the new kit came with a new connector and heat shrink but splices. No intermittent starting problems since. Except when the passlock system acts up. But like others have said, the truck will run for a second then just die. Good luck and keep us posted.