LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Considering going OBDI for new engine

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Old Sep 18, 2009 | 09:39 AM
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Default Considering going OBDI for new engine

Is there a writeup on what this takes? I know I will need an OBDI PCM, a small amount of wiring changes, knock sensor changes?
I thought I saw a writeup on this, but I can't find it now that I want to read it.
Thanks.
p.s. I want to go SD 2 bar with the new FI engine, and the tuning s/w and scanning s/w seems to be much cheaper and more accessible.
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Old Sep 18, 2009 | 10:13 AM
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Wiring changes? I did this a few years ago and only changed out the knock sensor and was good to go. I changed back because in my case there was no reason for it, and besides if you require emissions then you will be failed on the spot.
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Old Sep 18, 2009 | 11:04 AM
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So you just plugged the 94-95 PCM into the wiring harness and were GTG? Except for the knock sensor, of course. Madz28 sells an OBDI PCM for OBDII vehicles, and suggests that there were some major changes that he made to the PCM, hence the inflated price. I wonder if he incorporated the knock sensor change in the h/w in the PCM?
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Old Sep 18, 2009 | 11:11 AM
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Originally Posted by koolaid_kid
So you just plugged the 94-95 PCM into the wiring harness and were GTG? Except for the knock sensor, of course. Madz28 sells an OBDI PCM for OBDII vehicles, and suggests that there were some major changes that he made to the PCM, hence the inflated price. I wonder if he incorporated the knock sensor change in the h/w in the PCM?
You can wire in a resistor into the PCM or you can change the knock sensor. That is the only thing required to swap. If you want to easily swap between the two PCMs, then having one with the wired in mod makes it easier.
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Old Sep 18, 2009 | 11:26 AM
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Is there somewhere that tells me what value of resistor and where to solder it? That would be my preferred approach, and I have the tools to do the work if I just have the information.
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Old Sep 18, 2009 | 11:38 AM
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Looks like D22 is the Knock sensor input.
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