2015 SLT Fuel Pump?

[01SLE]

2015 SLT 4x4 49k miles

I'm guessing this is a fuel pump but if anyone has any other ideas please let me know. Only issue I've had with this truck is on cold starts it would take 2-3 seconds of cranking to start which is odd for any well running, newer vehicle.

I drove about 110 miles yesterday and 3 miles from home I was making a right hand turn into at an intersection and I lost almost all engine power. Engine stumbled around 300rpm and I limped into a parking lot before it died completely. Felt like half the cylinders quit.

I sat there about 3 minutes on my phone setting up road side assistance. It was hot as hell here, 119 degrees yesterday, so I wanted to move the truck into a shady parking spot. I hit the start button and it cranked for a good 5 seconds and fired up to a normal idle. I moved the truck 50 feet and it ran fine and shut it off. After another few minutes I wondered it I could just make it home because of the heat. The truck started right up and I hit the road. After 1 miles, the same thing happened and I pulled off the road. Tried to start it immediately and it cranked for 5-6 seconds and turned over into a stumbling idle at 300rpm before dying.

I waited another few minutes and tried again and 5-6 seconds of cranking into a smooth idle and made it another mile. CEL came on this time when it died. Did this one more time before getting home.

So basically the truck would start and run for a few minutes after a few minutes of sitting but not immediately after dying.

It absolutely felt and acted like a fuel delivery problem and the CELs are P2635 Fuel Pump A Low Flow, P018B Fuel Pressure Sensor B Circuit Range/Performance, P0506 Idle Air Control System RPM Lower Than Expected (pending fault), and a B2AAA (pending fault).

Seemed as though the fuel pump would overheat and stop. After a few minutes of cooling it would run then heat up shut off again. Fuel level was just over half a tank when this happened. Because of the previous cold starting issue, it makes me think that there's always been an issue with the fuel pressure delivery either a pin hole leak somewhere in the system causing fuel to drain back into the tank from the lines while off or the pump has always been weak.

Are fuel pumps covered by the 100k drivetrain warranty? I'm guessing not.

Any decent write ups/videos on 2015+ fuel pump access? I'm assuming I'll be dropping the tank

 

[01SLE]

Looked it up, The entire pressurized fuel system is excluded from the drivetrain warranty Thought I'd get lucky

 

[01SLE]

Might have found my own answer searching TSBs.

Manufacture communication PIP5411B

SUMMARY:
THIS PRELIMINARY INFORMATION COMMUNICATION PROVIDES INFORMATION TO THE TECHNICIAN ABOUT VEHICLES THAT MAY HAVE HESITATION OR A STALLING CONDITION WHILE IN AMBIENT TEMPERATURES 100 DEGREES OR HIGHER. TECHNICIAN MAY FIND DIAGNOSTIC TROUBLE CODES P2635 AND OR P018B SET. THE DEALER IS ADVISED TO REPLACE THE IN TANK FUEL PUMP MODULE ASSEMBLY TO CORRECT THE CONDITION.

Now I get to replace my fuel pump in 115 degree weather.... yay

 

[Kpwweb]

You may want to talk to the dealer--if it is a known problem they may replace it for you? Just sweet talk them and remind them you are an important customer...

 

[01SLE]

You may want to talk to the dealer--if it is a known problem they may replace it for you? Just sweet talk them and remind them you are an important customer...

Nope they basically just shrugged their shoulders. There response we its 12k miles out of warranty and its the first time they've heard of it happening. Their answer too the problem was $960.

 

[01SLE]

For anything searching in the future, I've been driving my Yukon without a repair with no issues. I wondered if the fuel pump was damaged or just couldn't handle the extreme conditions on that day. I tried driving in the early morning when it was under 90 degrees out and drove it on a day as hot as 114 and no ill effects. CELs turned themselves off the next day. I haven't added any fuel to the tank either to submerge the pump (for cooling).

So apparently the near record breaking temperature was the failing point. Now, every 15-16 Tahoe/ Yukon/ Escalade in Phoenix didn't stall that day so this obviously isn't normal. But at least I don't have to rush out and fix it just to drive it too the grocery store.

 

[dbbd1]

So it's working fine now, without the fuel pump being replaced?

 

[01SLE]

So it's working fine now, without the fuel pump being replaced?

Yes, its working perfectly fine. The extreme heat just made the fuel pump turn off, not necessary break. That day I also had to sit idling in a parking lot for 20 minutes waiting for my friends to meet up so im sure that heat soaked the hell out of the entire truck, especially the bottom.

Tonight I drove 20 miles in 107 degree heat and a little later 20 miles back home in 101 degree heart and everything was fine.

 

[dbbd1]

Great, thanks. And, thanks for the update.


Too often on these forums you never hear the final resolution/fix.

 

[01SLE]

I thought I'd follow up on this. I started experiencing other issues. The truck never flat out died again like it did in my original post. But I started to get hesitation at times under acceleration, a miss in the idle here every few seconds almost all of the time, and eventually the P018B code would come and go while highway driving but without performance issues or the truck dying.

So I spent the $190 for an ACDelco pump from Rockauto and replaced the pump myself a couple weekends ago and it drives like new again. My fuel economy had dropped down to an average of about 13-15mpg and now it's back up to 16-18 and over 21 on highway trips. The idle is rock solid smooth. I had assumed I had the phantom idle issue related to maybe the transmission alignment or something but it was inconsistent fuel pressure after all. Haven't had a single bump in the idle in 2 weeks. Another problem I could see in the tachometer is a flutter in the needle as it climbed sometimes. I couldn't feel a hesitation but I could see the needle move inconsistently and that's gone as well.

Swapping the pump was easier than I thought it would be. Disconnect the lower fuel filler hose by loosening the hose clamp and pulling it off the tank. Disconnect the 2 evap lines at the rear of the tank by hand which you can see and get to easily. They have clips you undo just with your fingers and pull them apart. Disconnect the fuel feed and return lines at the front of the tank by hand. They also have clips you under by hand and are easily accessible. Support the tank and remove the 2 bolts holding the straps with a 15mm socket. Lower the tank about 6 inches and reach up and disconnect the last Evap line by hand at the rear/top of the tank. This line runs over the frame so you can't lower the tank without disconnecting it first. Lower another 2 feet or so and disconnect the 2 electrical connections at the pump on top of the tank in the middle. And that's it, drop the tank. The pump itself is held in by a locking ring. Clean the hell out of the top of the tank, then use a hammer and screw driver to gently unlock the ring. It's pretty self explanatory when you see it. Pull the pump assembly out the top and disconnect the 1 line by hand. Clean the surface area where the pump sits, place the included new o ring, and reassemble in reverse order.