How To: Bleed 6.5L Fuel System

[West Mi Mudder]

Im just going to do a quick write-up of how to bleed the fuel system on a 1999 6.5L turbo diesel for the limited few of use with a 6.5L diesel. The process should be similar for most 6.5L, but may vary. This is a pretty simple process, but its always nice to have pictures when you are doing it your first time. (Which is what i would have liked, since i am also new)

This first picture is just a view of the engine bay from the drivers side fender.

You must be registered for see images attach

Next up, you want to find your fuse box. For those of you that dont know where thats at, its right next to the brake master cylinder.

You must be registered for see images attach

Now take the cover off the fuse box. After that, you have to remove the Fuel Pump Relay. On mine, this was the black relay at the bottom left corner.

You must be registered for see images attach

You must be registered for see images attach

Now that you have found the relay, and remove it, you need to open the breather on your fuel filter. Just a few quick turns to the left (Lefty Loosey, Righty Tighty) and it will be open.

You must be registered for see images attach

Now find a peice of wire you have laying around. Doesn't need to be anything special. I used a two inch peice of 18 gauge.

You must be registered for see images attach

You are now going to jump the fuel pump relay with this piece of wire. I tried to take a picture of the two sections to use your wire on, but it was kind of hard. So, if you look at the fuse like a U, you need to put on end of the wire in the top right, and the other end in the bottom left.

You must be registered for see images attach

You should be able to hear the lift pump working. If you don't, you either have a wiring problem or your lift pump is shot. If you do hear the pump, within a few seconds (depending on how much air is in there) fuel should start coming out. Stop jumping the fuse, and tighten down the breather on the filter.

Your half way done!:jump: *Hopefully*

Now find the T-handle. It is located to the left of the Oil fill/cap.

You must be registered for see images attach

Now just like the filter, your going to turn this a few turns to the left to open it up, and then go back to the fuse box and jump the relay the exact same way you did the last time. Soon you should hear fuel coming out. If its like my case, you'll hear it dripping on the ground. This is because Chevrolet put a drain hose on it.

The final picture is with me laying on the ground looking up. You can kind of see the drain hose. In the picture, its right above the two little bolt looking things in the middle :humm:

You may have to repeat this whole process to get it perfectly bleed. Hopefully this helps at least one person!

Good luck, and Happy trucking :c:

 

[tj98gmc]

gave rep!!,,, i remembered reading this before and i used it to bleed the fuel system when i did some upgrades today,, thanks man!!

 

[West Mi Mudder]

Thanks man! Im glad someone could get some use out of it. I know there is not a lot of 6.5L members on here, but there is quite a few anonymous users floating around. Im no expert, but if you need any help, let me know. Id be more than willing to share what i have learned with you.

 

[hookedup50]

My 97 has a plug behind the fusebox that you can use a jumper wire and do same thing. Thanks, my LP wasn't priming and didn't know how to test the relay that was bad. Now I do. Thanks again.

 

[melamed555]

Hey I had a question about the priming process. I have a 1995 GMC K2500 6.5 Diesel, I am changing the lift pump and oil pressure switch today and I wanna bleed the fuel system just to make sure theres no air in there. Someone told me that I have to loosen each nut for each injector individually until fuel comes out and then I could be certain there is no air in the system. Does doing your method do I not have to worry about loosening each injector. Your system does the same thing, correct?

 

[skylark]

The above method just gets fuel to the injection pump. I usually crack the drivers side injector lines and crank it over until fuel comes out. I then tighten the injector lines and then fire it up. It will run rough on just those 4 cylinders and self bleed the passenger side while it is running.