P050D Fuel Injector Drop Explained.

carnau · June 18, 2019

Ok so I wanted to post a little explanation of how I personally test the P050D code to find out if my injectors are bad or not. This also works for High or low fuel trims.

So Here is the injector drop on a bad set of injectors in a 2016 Silverado.

Here is the same truck after the injectors have been replaced. So brand new injectors.

Now. With the new set of injectors if we follow the GM guidelines for testing the injectors. We should add all of Each bank up. So 1,3,5,7 and 2,4,6,8 then multiply it by 0.20 and that's the allowable drop.

(1,3,5,7) = 134.8/4 = 33.7 x 0.20 = 6.74

(2,4,5,8) = 175.4/4 = 43.85 x 0.20 = 8.77

So bank 1 each injector should be above 26.96 and below 40.44

And Bank 2 each injector should be above 35.08 and below 52.62

Or if you wanted to add all 8 together you can do 1 drop for the whole vehicle.

310.2/8 = 38.78 x 0.20 = 7.76

So every injector should be between 31.20 and 46.54

The problem I have with this method is bank 1 has farther to go to be over fueling and bank 2 has farther to go to be under fueling. That's why I like to do each rail separately.

Now with that being said. I have not run into any over fueling injectors yet. Doesn't mean I won't but I have a pile of under fueling injectors and here is my rule of thumb.

If it under 26 on bank 1, I am replacing those injectors. If it is under 36 on bank 2. It is getting those injectors. Following this method has not let me down yet.

Here is a video on replacing the fuel injectors as well. I hope this helps everyone, and at least gives you some kind of explanation on the P050D, P0174 and P0175.

If you have any questions, send me a message or follow me on Twitter @cdarnau and send me a message there. I will be glad to help you as much as possible.

silveradosid · April 8, 2020

just found this post and thank you. why would there such a difference on pressure between bank 1 and bank 2. i am going to run this test on my 2014 and see if it is the same result in differences, trying to figure out why my truck vibrates bad when it switches to 4 cylinder mode

Eddie 70 · June 3, 2020

Awesome video. It seems you have done this more than once. Thanks for taking the time to make the video. I saved the it on youtube so if it ever comes around and I have these problems, I can refer to it to make the replacements. I am currently at 111k miles so no telling.