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2001 Silverado V6 - slow start, hesitation on highway?


zeitgeist57

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  • 2 weeks later...

I really don’t see it being a crank sensor, they typically work or they don’t. Short of an occiliscope, a scan tool that will show the rpms incrementing is how most techs do it. There are some rather expensive test probes that show a wave form, these have become more popular amung techs lately but I don’t have one.

 

I assume you were checking fuel pressure when you were driving under load? and when it’s taking time to start?

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We tested cold cranking pressure but not under load.

 

When we hooked up the gauge the pressure was at zero but as soon as the pump came on it shot up. In thinking about it now, the line pressure may be bleeding down overnight? In my jeep the fuel rail holds pressure, is it supposed to in a 4.3?

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Well it sounds to me like you haven’t ruled out a fueling issue. Just remeber the engine requires more volume when running down the road. I’m not saying it’s the slow start problem, but could certainly cause a hesitation. You need to leave the gauge on it after you shut it off and see how long it takes to bleed off. Unless it drops like quickly or doesn’t bounce right back up when you turn the key to run (fuel pump prime), then it’s not causing the slow start. When you screw any fuel pressure gauge on it’s going to read low until you run it and fill the gauge/hose with fuel. You really have to have the gauge on the vehicle and be watching it when the vehicle screws up, if the vehicle is screwing up and your fuel pressure is around 58psi then you can rule out a fuel supply issue.
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