High Pressure Fuel Pump

nwolfe20 · October 30, 2021

Currently working on my neighbor's 2014 GMC Sierra 1500 5.3 with a running rich condition. After following the technical bulletin including our fault code we found that the high pressure fuel pump is leaking fuel into the engine. I found the part but my neighbor is looking for a cheaper option. I've searched and searched for rebuild kits but I'm having no such luck. We're going to let it sit for now and hopefully we can find a kit. I plan on pulling and old off at a junk yard to tear down and see what we're dealing with.

14burrito · November 11, 2021

On 10/30/2021 at 9:24 AM, nwolfe20 said:

Currently working on my neighbor's 2014 GMC Sierra 1500 5.3 with a running rich condition. After following the technical bulletin including our fault code we found that the high pressure fuel pump is leaking fuel into the engine. I found the part but my neighbor is looking for a cheaper option. I've searched and searched for rebuild kits but I'm having no such luck. We're going to let it sit for now and hopefully we can find a kit. I plan on pulling and old off at a junk yard to tear down and see what we're dealing with.

Can you elaborate more on "high fuel pump is leaking fuel into the engine".

Into the engine compartment?

If your having wet crowns its likely the injectors are bleeding as that's the last fuel component going into the cylinder.

FYI for a high pressure pump recall

https://www.google.com/url?sa=t&source=web&rct=j&url=https://static.nhtsa.gov/odi/tsbs/2015/SB-10057680-1621.pdf&ved=2ahUKEwjQhtHYpZH0AhWUbs0KHbWrDPQQFnoECAsQAQ&usg=AOvVaw1qP5RhS1ZZnpgcP3CQCVWd

Edited November 11, 2021 by 14burrito

M1ck3y · November 15, 2021

I think he's saying the fuel pump is responsible for creating a rich condition?

I don't know much about how this system operates but I don't think that's possible. The injectors are controlled by the ecm. How much fuel, when, and how many times an injector fire's during any given combustion event is controlled. It's not affected by the pump unless it's not providing enough pressure.. Or too much pressure?

Edited November 15, 2021 by M1ck3y

14burrito · November 15, 2021

11 hours ago, M1ck3y said:

I think he's saying the fuel pump is responsible for creating a rich condition?

I don't know much about how this system operates but I don't think that's possible. The injectors are controlled by the ecm. How much fuel, when, and how many times an injector fire's during any given combustion event is controlled. It's not affected by the pump unless it's not providing enough pressure.. Or too much pressure?

The way it reads to me: they were diagnosing rich running, found the high pressure pump leaking into the engine (fuel leak under the hood).

That's why I was curious about more details.

If the high pressure pump was over/under supplying I would be led to believe that the fuel rail would register a fault for low fuel rail pressure or rail pressure too high.

I'd be suspect of the injectors leaking or sticking.

What codes was he getting? Bank 1 or 2 rich? Then he could just swap injectors between banks and see if the rich running condition follows the injectors. (Providing he doesn't have a flaw bench)

Rich condition only registered at start-up? Injectors could be bleeding causing excess fuel upon engine start and the condition rectifies once fuels burned.

Etc etc

I'm curious more details.

Edited November 15, 2021 by 14burrito

nwolfe20 · November 15, 2021

Both banks were rich. It only throws the codes when the truck idles for an extended period of time. My scan tool had a tsb attached with the codes and once we followed through its troubleshooting guide it led us to the high pressure fuel pump. I didn't know there was a recall on them.