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Discussion Starter #1
ok i had the pcm retuned to fix the bugs and the 02's still dont read. they hang around 0.450 and fluxuate from 0.445-0.455.. and its stuck in open loop.

Im using the 411 PCM and used a 03+ Harness but wired it all to a 02. I tore the whole thing down and built it from scratch. i didnt just repin it to work.. Currently i have the 02's wired:(from the 02 plug), Blacks are going to ground, pinks are going to ignition, tans going to the right spot on the pcm(26,29), purples going to the right spot on the pcm(66,69) (dont qutoe me on the cavities im not looking at a diagraam right now) and im getting 0.450 on my scanner and check engine lights of no 02 activity bank 1 and 2.

so ive found searching here this:
As for the wiring, you need to add wiring for the IAC motor and THROTTLE POSITION SENSOR (TPS). You can use the Oil Pressure sensor plug as a TPS plug, (computer does not need to know oil pressure) You will need to find a IAC plug. Almost any older GM vehicle will have this plug, check local parts yard or maybe a parts counter can get a replacement plug. Typically the IAC has two light green, and two light blue wires, one each with black stripe and a white stripe.
Here is a chart that will show the wire color, description, and where the wire needs to go in the PCM plugs. The wire color on the TPS assumes you are using the oil pressure sensor plug. (the 5v ref and low ref ar opposite between oil pressure and tps) I give specific pin locations that WILL work for 5 volt & low reference, however, you could just switch the BLACK and GRAY at the TPS plug, and then move the Oil Pressure Signal wire (TAN) FROM GREEN 58 to GREEN pin 24. If you don't switch the black & gray, the TPS will work backwards.
Throttle Position Sensor (using oil pressure sensor plug) WIRE DESCRIPTION PCM PLUG / PIN LOCATION GRAY LOW REFERANCE BLUE PIN 60 BLACK 5 VOLT REFERANCE BLUE PIN 8 TAN TP SIGNAL GREEN 24 Idle Air Controller Valve WIRE - IAC PIN # DESCRIPTION PCM PLUG / PIN LOCATION LT GRN/BLK PIN A IAC COIL B LOW GREEN PIN 77 LT GRN/WHT PIN B IAC COIL B HIGH GREEN PIN 76 LT BLU/BLK PIN C IAC COIL A LOW GREEN PIN 78 LT BLU/WHT PIN D IAC COIL A HIGH GREEN PIN 79 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.
That is it. To understand WHY we had to hook in the TAN wires, please read the OXYGEN SENSOR info page.
*****If you found this page helpful, please let me know, by all means. [email protected]


I Tried wiring it this way. (Basically grounding the tan) and it put it in closed loop, Runs rough as Heck, Rich as well, Dumps fuel, Black smoke, wants to die, and the 02's read 0.000..

I cannot firgure this out at all. any help its greatly appreciated..
 

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Call me Mario, Princess
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I had this same problem when I first wired my truck. I needed to add a ground to pin 63 in the blue connector and tie it to the tan wires at 26 and 29 in the blue connector.
 

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Discussion Starter #4
It's the case ones. Square white 4 pin not the flat 4 pin.

So add a wire to pin 63, ground it, and tie it into the tans..
 

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Discussion Starter #5
So... Added the ground to pin 63 and grounded the tans in that loop. Oxygen sensors seem to work. But getting code. P1153 and p1133. I'm guessing the brand new delco sensors are bad. Going to exchange them tomorrow. Also noticed drivability issues. It falls flat on its face and has no power until I come to a complete stop then check engine light pops up and drives like normal. This is after resetting the light.
 

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Call me Mario, Princess
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did you have somebody tune it with a wideband to create your ve table or is it still stock?
 

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Discussion Starter #7
im not sure what the VE table is.. Im going to assume its stock.. My truck was not tuned with a wideband when it was tuned..
 

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Discussion Starter #8
Let me rephrase that. It will run and drive fine and out of nowhere will fall on its face with no power until I come to a complete stop and then the check engine light pops up and will run and drive fine.. That's after resetting the light
 

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Call me Mario, Princess
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then the fueling is probably all wrong and causing a lot of the problem. It may be so rich or so lean the computer can't compensate for it.
 

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Call me Mario, Princess
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sounds like the problem is when it is in closed loop. with out a log of some sort we're just shooting in the dark.
 

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Discussion Starter #11
Yes the problem rises when it's in closed loop. I believe that when I come to a stop when it falls on its face it switches over to open. I have a scanner that shows live data but haven't had it on it when it does the falling on its face.
 

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Yes the problem rises when it's in closed loop. I believe that when I come to a stop when it falls on its face it switches over to open. I have a scanner that shows live data but haven't had it on it when it does the falling on its face.
Using a MAF?
 

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Discussion Starter #14
Any other thoughts? I exchanged the 02's today. Got new ones. I have some used ones in it now and got a few other codes. But going to assume those are due to used ones being in there.
 
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