Mechanics

K3500 DUALLY SLOW STARTING

1998 Chevrolet Truck

Hi, I have a 1998 Chevy K3500 crew cab dually with a Vortec 7.4 liter (454) engine.
It has 105,000 miles.
When the truck sits over night, it starts immediately with no hesitation or starter whirling. Bump the starter and it starts. If, after driving or running it, it sits for up to 12-15 minutes, it starts immediately, no hesitation. If however, it sits for more than 15 minutes, but less than 8 hours, the starter whirls the engine around but the engine doesn't start for about 10-15 seconds. I've had the fuel pump and filters replaced. They've replaced a vacuum hose that was damaged and replaced the spark plugs. They (professional mechanics) tell me the distributor cap and rotor cap are fine. They are clueless at this point. This problem has been ongoing for about 40,000 miles. I typically run unleaded regular fuel, but about every 10 tanks run 1 tank of premium. My repair shop has a mechanic who has a 1998 3/4 ton Suburban with the same engine which has the same problem and they can't fix it either. They have told me to just live with it. I would really like to get this fixed. The truck did not do this when I bought it and it had 12,300 miles on it when I bought it. The problem did not start until after about 60,000 miles.
No codes are being thrown nor are any indicator lights on I.E, Check Engine, Etc.
Help please! Thank you!
AD
Avatar
Mphipps8849
April 3, 2007.



Check the fuel pressure regulator.

Tiny
Jack42
Apr 4, 2007.
Thanks, but that has been done. I was unaware they'd done that when I made the original post. I've talked with the shop since and they did a fuel pressure test and also physically pulled the intake manifold and visually tested the fuel pressure regulator. According to the shop, they've installed two new fuel pressure regulators on the mechanics Suburban and it did not fix the starting problem on it. They have also ruled out the temperature sensor that feeds the computer for the cold-start circuit.

Tiny
Mphipps8849
Apr 4, 2007.
An EGR that is crack open will create a huge vacuum leak that will prevent an engine to start immediately BTDT 34yrs ago and it gave me hell to figure it out. Back then there's no idiot lite to warn you about the EGR.

Mr. Jack gave you the fuel pressure regulator what's with this-get it done might lead you to something. Here's more for your problem

When the pump is turned off or stops running, the system should hold residual pressure for several minutes (look up the specs to see how much pressure drop is allowed over a given period of time). If pressure drops quickly, the vehicle may have a leaky fuel line, a leaky fuel pump check valve, a leaky fuel pressure regulator or one or more leaky fuel injectors. Low residual fuel pressure can cause hard starting and vapor lock during hot weather

Let me know when you need more

HTH Good Luck Happy Easter
AD

Rasmataz
Apr 5, 2007.

AD