2007 Tahoe LTZ 6.0 Swap Problems

[Ryno21]

So the Tahoe is running well. I still need to have some programming done, but I have an appointment with the most competent local guy I can find, so we'll see what he can do.

I have noticed that the gas mileage readout and the odometer on the dash are not correct. They are off by about a factor of 4 (it says I go about 2.8 miles, when I actually drive 10 and the mpg is terrible ~3.6). Is this internally calculated and stored in the dash cluster? or is it something that the ECM calculates and just feeds to the dash cluster?

I am debating swapping out the dash cluster since that's a simple thing. Also, I bought a shift lever with the +/- shifter on it so I'll work on that swap too. Anyone know if that is easy to do? I know the shifter bolts right up, but the plug is different. Not sure if the stock plug on the column can be modified (it has 4 wires) to fit the new column shifter (4 wires). The old shifter only has 2 wires coming off of it. Is there programming that needs to be done also? or if I modify the wiring, would it work and I could manually shift it?

Good news is that the actual gas mileage seems to be up with the new drivetrain and it definitely pulls a little better!

 

[Ryno21]

Update on the swap for anyone who is interested:

I ended up taking the Tahoe to another auto repair place, where the owner actually knows what he is doing. He took the time to go through electrical diagrams for both vehicles and figure out the problems I was having.

First, they UNDID everything the dealership and other auto repair place did...ALL of it. Now every module is back to stock.

Second, they left the 6.0 ECM alone, along with the transmission. No programming necessary, contrary to most of the advice I received from several sources.

Third (most important), they had to swap 4 pins and add 4 pins on the TCCM wiring harness plug, and I bought a new TCCM for the 2009 suburban that the powertrain would have come out of (Like $50 used local). No more stabilitrak, abs, traction control, or service 4x4 codes!

The vehicle was up and running better than ever within a couple days. The 4x4 works and everything has been great for a couple months now.

As of right now, I am still having a hard time getting someone who can program the radio to re-learn the new VIN (in dash dvd, rear entertainment, navigation). The fuel gauge is the only other thing not working and there is a check engine light on "fuel rail A circuit high" or something like that. This is due to the Suburban having 2 fuel tanks and the Tahoe only 1. The owner of the shop is working with a couple people he knows who say they can fix it, but I need to find time to take the ECM out and send it to them. He says they can fix it, I just have to have time to do it and pay for it of course.

Bottom line: it's worth every bit of time you spend finding a COMPETENT shop for something as custom as this. Someone who will take the time to do the research and do the job right, rather than try things at your expense!

 

[Ryno21]

The Tahoe has been working very well for a while now. I like the new engine setup. It definitely tows better and it gets pretty much the same gas mileage (better than my 08 Sierra 1500 with the 5.3 and 4L60).

I had to get it registered and I needed to do emissions and safety tests. During the emissions test, it failed due to a check engine light being on. The light is due to the P2068 engine code. I was looking things over and I noticed that the wire colors seem different on the plug that comes off the engine wiring harness at the back of the transfer case. It comes off the transfer case and over the frame just before the fuel tank. I'm just wondering if someone could provide me with wiring diagrams for this plug showing pinouts for both vehicles (2007 Chevy Tahoe & 2009 Chevy Suburban 2500).

I suppose I'll look at the pins and try to measure the voltages to see if I can tell if something is going on wrong. Besides the code, the fuel gauge still doesn't read anything. I assume it's related to the code.

Thanks for the help in advance.