Any Silverado mechanics here? 2000 starting issue.

[BReeves]

Hi Folks,

Couple years ago I bought a 2000 Silverado 5.3L, 4WD for the occasional snow and ice we get plus a lumber hauler. Has 259,000 on the clock but runs great once it starts. A commercial truck that was well maintained.

The symptoms are kinda strange. When it's hot outside +80 deg I have to turn the key to start, let it turn over a second shut it off then on the next try it will start right up. This time of year with the temps below 50 it will start first time every time. I noticed the change relative to outside temps last winter but now I am sure. At first I thought it might be the fuel pump check valve but you can grind on it all day long the first try and it refuses to start, turn the key off and it will start every time on the 2nd try. Swapped out the fuel pump relay just for grins but didn't help. Fuel pressure regulator was replaced just before I bought it.

Any ideas on what would be effected by the outside temperature that would keep it from starting on the first try?

Thanks...

 

[Fyrtwuck]

Does it have a computer system on it? Take to O'Reilly's and they will do a diagnostic check for free. Might be able to find out something there.

 

[excat]

Could straight up be a bad fuel pump that is losing it's prime/pressure? My wife's Nissan did the same, but at all temps, and it was a weak fuel pump. Swapped it out, and it was good to go. Also, may as well replace the fuel filter in case it is clogged partially and part of the problem.

If you have access to a fuel pressure gauge, hook it up on the fuel rail, and have someone crank it the "first" time, and see what your pressure is doing when you are having the no start, then do it the second time to see if it reads different when it starts up.

 

[travisstorma]

Very common issue for these trucks. It usually is the fuel pump. Try to turn key to "on" (not start) position, let pump prime for a couple of seconds. Turn key off. Then try to start it.


What happens is that the pump doesn't build enough pressure in the fuel system in the short prime time. I'd have to break a book out, but I don't think that it commands the pump on in the crank position, just when the PCM senses that the engine has started after the initial prime.

 

[piston10]

If it's the one I'm thinking of, pull the vac line off the fuel pressure regulator on top left side of the engine and if gas comes out of the vac line replace the regulator. If not, sounds like possibly a fuel pump.

 

[piston10]

This. When pulling the rubber vac line off it should be dry. The picture shows the line already removed. The line at the top of the picture is wet. That would be a bad regulator.

 

[eyecyou]

Fuel pump definetly. When its hot outside the pump is vapor locking and will not build enough pressure. Very common problem. Next time it wont start keep crankin and put the pedal to the floor

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[sh00ter]

Fuel pump definetly. When its hot outside the pump is vapor locking and will not build enough pressure. Very common problem. Next time it wont start keep crankin and put the pedal to the floor

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does pedal pumping work on a fuel injected vehicle? I thought that was only for carbs?

 

[eyecyou]

In this situation yes. The computer sees wide open throttle and demands more from the fuel pump

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[piston10]

does pedal pumping work on a fuel injected vehicle? I thought that was only for carbs?

I have never found that to work if it's a fuel pump.