Originally Posted by TTBlueZ06

first of all you need an 04 express van pcm "p59" with any of these serv number and hardware no.

2004: Serv. No. 12586243 with Hwd. No. 12583659
2005-2006: Serv. No. 12589462 with Hwd. No. 12589161
2007: Serv. No. 12602801 with Hwd. No. 12589161

since you arent converting to a cable throttle body (i presume) then all you need to do now is get a tune for your setup and to get the flex fuel sensor and to pin it to the computer. If you are going to use the oil pressure switch and oxygen sensors then you need to do the following :
"If you have a RED/BLUE connector PCM, you CAN use this pcm on a 03+ harness (GREEN/BLUE connector) with cable throttle, with a few simple modifications. The only thing that needs changed, other then what was talked about above, is some of the oxygen sensor wiring. On the 2003+ blue/green connector PCM's, the PCM supplies a GROUND for the oxygen sensor heater's, and 12v+ comes from the fuse block. In the 99-02, power and ground is fed directly to the o2 sensor heaters. To make the changes needed to 2003+ blue/green harness, to work with a blue/red computer is this:

REMOVE: BLUE PCM connector pins: 24,27,64,67. These should all be black with white stripes. These were extra ground wires provided to the 03+ pcm so it could control ground to the o2 heaters. The 99-02 pcm does not need these. Just pull the pins out, don't cut anything yet, we need to hook these to a few other wires we pull out of the PCM connectors.

Next we need to remove the wires from the PCM connector that go to the oxygen sensor heater control. There are 4 wires, one for each oxygen sensor. If you are only using front oxygen sensors in you conversion, omit anything to do with Sensor 2.

Bank 1 Sensor 1 - BLACK/WHITE - GREEN connector pin 72

Bank 1 Sensor 2 - BROWN - GREEN connector pin 52 - after CAT o2 sensor

Bank 2 Sensor 1 - LT GREEN - GREEN connector pin 74

Bank 2 Sensor 2 - RED/WHITE - GREEN connector pin 53 - after CAT o2 sensor

Now, you should have 4 ground wires, and 2 (or 4) oxygen sensor heater control wires pulled from the PCM connectors.

You need to locate the 4 tan oxygen sensor low reference wires going into the BLUE pcm connector. If just using front o2 sensors, its BLUE pins 26 and 29. If also using rear o2 sensors, add pins 25 and 28. These wires will always be TAN and may have a white stripe. The easiest way I can think of to splice into these, is pull the pin out (REMEMBER WHERE IT GOES BACK) remove some insulation with a knife, solider on a wire, and slip some heat shrink up and past the terminal and shrink the heat shrink down over the splice. Then reinstall the pin in its original location. Leave about 12" of wire loose for each wire you splice into. Do this for all the o2 sensors you will be using.

So at this point. You should have 4 black/white ground wires loose. 2 to 4 oxygen sensor heater control wires loose, and 2 to 4 wires going to each of the TAN wires. All of these wires need hooked together in a big splice pack. First get some larger heat shrink, 1/4 or 5/16 should work. Put about 4 inch long piece of heat shrink over all 4 ground wires. Next strip off about 1-2 inches of insulation off all your wires. Start hooking them together end to end, you should be able to solider all these together, and slip the heat shrink over when done.

The last step, is to make the connectors fit inside the PCM. This will require cutting the rib off the GREEN plastic terminal cover, so it will fit in the RED pcm socket.

You will need to use oxygen sensors for a 2002 chevy truck, 5.3L, will be a white plastic connector, and will plug right into the 03+ harness without changing plugs."


You will need a FF sensor and this pigtail connector

you will need to plumb this sensor in the return line to prevent any restriction as its a 3/8" diameter orifice.

once plumbed, the wiring will need to be plugged in the sensor and the other end will be cut off.

wire A will go in pin 56 in the BLUE connector in your computer.

wire B (the middle one) goes to a switched power source.

Wire c goes to just any ground.

The rest you will need your tuner to activate the sensor and populate the flex fuel tables. After you have done this, your tuner should be able to work out the kinks and all that good stuff, you should have flex fuel capability, 3 bar, and fueling and timing on the fly.

Originally Posted by Milan

MAF? Who is that applicable to in this forum?

So your approach is to tune on 100% gasoline, then do another tune on E98 and have the ECU be able to interpolate the values in between with 100% accuracy?

Originally Posted by FEAR LS

It could be done, but anything can be done if you are willing to spend the money.

The PCM would have to be from a flex fuel capable vehicle as you had already stated, in addition you would have to ensure the ignition system on that pcm isn't setup for a 58x reluctor vs the Gen III 24x. As well as the crank and cam position sensors. Whether it was data that needed to be input or wiring/conversion or both.

These are things just to think about, I haven't done one before. Although I know I'm fully capable, just don't have the budget at the moment to convert mine.

The above is extra, meaning not including the fuel system upgrades it would require. (Pump(s), lines, injectors, etc...)

Originally Posted by hodge9386

Did you just get the red/blue green/blue thing confused when typing this or do we just need to work backwards off this to put a blue/green pcm in our cars?

Originally Posted by hodge9386

and why would you want to go backwards from a green/blue p59 to a red/blue p01?