Crazy stuff

[Rob Yukon]

My 2000 GMC Yukon Denali wouldn’t start this morning. I had pumped the gas 3 times like my neighbor said, and no start. So I came home from work and did what I’ve been doing and cranked it twice and it fired right up. I don’t know why I have to crank it twice but I do. After I start it it will start right up. It only does it after it sits overnight or after it sitting all day at work. Weird right

 

[Mudsport96]

Fuel pump check valve is bad and letting the fuel drain back to tank overnight. Don't need to pump the gas, that went away with carburetors.

 

[ivin74]

^×2

 

[Marky Dissod]

My 2000 GMC Yukon Denali wouldn’t start this morning.
I had pumped the gas 3 times like my neighbor said, and no start.
So I came home from work and did what I’ve been doing and cranked it twice and it fired right up.
I don’t know why I have to crank it twice but I do. After I start it it will start right up.
It only does it after it sits overnight or after it sitting all day at work. Weird right?

Instead of cranking twice, or pumping the gaspedal 3x,
Turn the key to the On-Run position without starting it, and wait 3-5sec.
Turn it back away from On-Run, then turn the key to the On-Run position again.
Wait 3-5sec, THEN start it. I bet it starts.

Explain that to a 1/2way decent mechanic.
They SHOULD be able to fix the problem without diagnosing it for several hours.

 

[Rob Yukon]

How do I fix the check valve?

 

[1968charger]

New fuel pump

 

[Rob Yukon]

Instead of cranking twice, or pumping the gaspedal 3x,
Turn the key to the On-Run position without starting it, and wait 3-5sec.
Turn it back away from On-Run, then turn the key to the On-Run position again.
Wait 3-5sec, THEN start it. I bet it starts.

Explain that to a 1/2way decent mechanic.
They SHOULD be able to fix the problem without diagnosing it for several hours.

I tried that this morning and it worked. Thanks

 

[Marky Dissod]

Note that

Instead of cranking twice, or pumping the gaspedal 3x,
Turn the key to the On-Run position without starting it, and wait 3-5sec.
Turn it back away from On-Run, then turn the key to the On-Run position again.
Wait 3-5sec, THEN start it. I bet it starts.

Explain that to a 1/2way decent mechanic.
They SHOULD be able to fix the problem without diagnosing it for several hours.

I tried that this morning and it worked. Thanks.

Don't forget to explain what's going on to your favorite mech.
It's not like I fixed the problem.

 

[Rob Yukon]

Update. I have also replaced the o2 sensor that was kicking the code. No check engine lights and she starts right away now.

 

[Fless]

I'm not sure that pumping the footfeed (thanks, Dad, for that word) does any good when starting a fuel injected engine. It's not like the accelerator pump on a carburetor.

 

[strutaeng]

I'm not sure that pumping the footfeed (thanks, Dad, for that word) does any good when starting a fuel injected engine. It's not like the accelerator pump on a carburetor.

I think cycling the ignition twice helps build more pressure (like if it's a low pressure issue.) Basically priming the fuel system twice could increase the pressure a few notches higher such that the injectors can actually fire.

...I guess I'm confused... Isn't a 2000 GMC Yukon Denali a carryover of the GMT400 line? There's a huge difference between those and the later generation on the fuel injection and ignition systems.

 

[Marky Dissod]

Isn't a 2000 GMC Yukon Denali a carryover of the GMT400 line?

Considerable overlapping between GMT400 & GMT800 1500 pickup trucks in '99 & '00,
and GMT400 & GMT800 1500 suvs in '00.

 

[Fless]

...I guess I'm confused... Isn't a 2000 GMC Yukon Denali a carryover of the GMT400 line? There's a huge difference between those and the later generation on the fuel injection and ignition systems.

Good question, but unless one knows that particular year's build style, it's just a guess. The OP didn't say which engine was in it, not that I saw in the posts.

 

[SilverSport]

should still be the GMT400 in that...I had a 2000 Escalade...it also was still GMT400 based

Bill