Fuel rail pressure

[Brandon johnson]

Starting my 07 Yukon XL Denali after it sits for a while doesn't start right away. It cranks over but doesn't start. Try starting again and fires right up. No codes on the das and it idles and drives fine. What's the problem?

 

[swathdiver]

What kind of fuel are you feeding it Brandon?

 

[Brandon johnson]

What kind of fuel are you feeding it Brandon?

Mid grade 89

 

[swathdiver]

Might want to run some Top Tier 93 through it and drop in a couple bottles of SuperTech Fuel Injector Cleaner from Wally World. Start with the simple.

If you have access to an advanced scan tool, look at the fuel pump and injectors and such. After 11 years, the top of the tank, the fuel pump area might be rusty and rotting and leaky but don't bother with that until the easy stuff has been done first.

 

[Brandon johnson]

Might want to run some Top Tier 93 through it and drop in a couple bottles of SuperTech Fuel Injector Cleaner from Wally World. Start with the simple.

If you have access to an advanced scan tool, look at the fuel pump and injectors and such. After 11 years, the top of the tank, the fuel pump area might be rusty and rotting and leaky but don't bother with that until the easy stuff has been done first.

I have ran 20 gallons of treated fuel thru it and plan on doing more but if it was one of those electric valves or sensors, wouldn't it throw a code? I have no dash lights.
Thanks for a fast reply.

 

[swathdiver]

Yes, it should throw a code if one of them is bad or out of spec even if there's a wiring problem usually. Don't mention it, happy to oblige.

 

[HiHoeSilver]

Do you smell gas at all? After you've driven it a little bit, shimmy under and look at the passenger side of the gas tank to see if it's wet.

 

[Brandon johnson]

Do you smell gas at all? After you've driven it a little bit, shimmy under and look at the passenger side of the gas tank to see if it's wet.

I will check that tomorrow, it's been rainy. But what would this point to if there is gas there?

 

[HiHoeSilver]

I will check that tomorrow, it's been rainy. But what would this point to if there is gas there?

As @swathdiver said, the lines on the head of the pump like to rust out.



This causes loss of pressure and then some long starts.



As you can see, there's a valley on top. If it's leaking, it will find its way down the passenger side.

 

[Rocket Man]

As @swathdiver said, the lines on the head of the pump like to rust out.

View attachment 200469

This causes loss of pressure and then some long starts.

View attachment 200470

As you can see, there's a valley on top. If it's leaking, it will find its way down the passenger side.

Was that yours?