2011 Yukon XL 2500 Duramax Conversion

[drbird123]

Just thought I would start a thread on my conversion. It is a 2011 Yukon XL 2500 and I am putting in a 2011 LML Duramax drivetrain. Body just went back on yesterday but I will catch you up in the next posts.

 

[drbird123]

Yukon and Donor Truck

 

[M.A.M.]

Subd for future reference!!

 

[drbird123]

So the actual engine swap was pretty easy but the fuel system was a bit of a bear. I ended up using the Duramax sending unit and modified it to fit in the shallower gas tank in the Yukon. I left the gas tanks from the Yukon as they were dual tanks and I didn't want to lose the rear tank. You can't fit the Duramax fuel tank in this frame. On the Yukon gas sending unit you have an extra hose that comes from the rear tank and dumps into the front main tank when it is getting empty so I put the hose with the white clip on the little breather nipple which is separate from the main 5/8' breather line. Another guy said he did this and it worked fine. As for the fuel filler part I read a lot of problems with not being able to fill up the tanks fairly fast because the filler from the gas was so small so I modified this as well with the Duramax one which is 1-1/2" hose. I ended up using a plumbing T from the hardware store as I couldn't find anything else. Here are a couple pics.

 

[drbird123]

One question I have is about some wires on a connector from the harness that goes down to the transmission from X1 X2 & X3, there is a little tail of wires that comes out and plugs into another connector from the wire harness on the frame of the Yukon. It is just before the ABS/Stabilitrak module towards the front. Here is a picture. The connector on the left is from the duramax tranny harness and the one on the right is from the yukon harness thats on the frame. Pretty big difference.
Here is what I was thinking so far about how it should be wired. I attached the Gas X1 drawing showing the wires highlighted that go to the connector on the frame of the Yukon and then i attached drawings of X1, X2 & X3 with the wires that go down to the Duramax Connector. There are seven wires I need to figure out on the yukon connector on the frame and they are for the fuel system mostly.
Gas pin 16 Fuel Level Sensor Signal Primary
Diesel pin 58 Primary Fuel Level Sensor Signal X1

Gas pin 24 Fuel Tank Pressure Sensor Signal
Diesel pin 44 Fuel Filter Pressure Switch Signal, Not sure if I can use this???

Gas pin 31 Low Reference
Diesel pin 44 Low Reference on X1

Gas pin 33 5 Volt Reference 1
Diesel pin 43 5 Volt Reference 1 on X1

Gas pin 51 Fuel Pump Relay Control Secondary
Diesel Still not sure about this one??

Gas pin 57 Vehicle Speed Signal
Diesel pin 27 Vehicle Speed Signal on X2

Gas pin 61 EVAP Canister Vent Solenoid
Diesel Not to sure what to use?

Gas pin 70 Secondary Fuel Level Sensor Signal
Diesel pin 3 Secondary Fuel Level Sensor Signal on X3

 

[drbird123]

Diesel Drawings X1, X2 & X3

 

[TheBac]

Moved to Repower/Transplant

 

[bmc1025]

What tells the rear pump to activate? I know on the 07-10 models you have to have the Cab and chassis tune or at least the fuel segment in order for the rear pump to fill the front tank. Just an Fyi that may help you out.

 

[drbird123]

Yes for sure I think this is the wire to use for that. The gas was pin 70 and on X3 on the diesel it looks like it is pin 3.

Gas pin 70 Secondary Fuel Level Sensor Signal
Diesel pin 3 Secondary Fuel Level Sensor Signal on X3

I do have a buddy with EFI Live to do the proper tune for me so as long as my wires are correct I am all good!!

 

[drbird123]

Ok she is all back together!!! Just need to figure out the wiring changes and I can start her up!! Does anyone know or have a list of wires that need to be re-pinned at the fusebox?

 

[oscyjack]

Sub