OBDII -> OBDI Conversion on '97 LT1
01-29-2014, 03:50 PM
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OBDII -> OBDI Conversion on '97 LT1
I picked up a '95 LT1 a couple weeks ago to start a mild build for my '97 SS.
The motor I picked up was a complete pull so I got the wiring harness, OBDI computer, starter, alternator, etc. I'm considering doing an OBDI conversion as well to make tuning easier. The '95 won't make it into the car for a while (probably a couple years) so I'm kind of considering doing the OBDI swap ahead of time as I've wanted to tune my car for a while however the aftermarket for OBDII LT1 tuning is pretty sparse.
I was thinking of sending my OBD1 PCM to Ion then having him set it up for my car as is. As far as the swap goes, it's simply plug and play? Just plug in the OBD1 PCM then drain the coolant and install the new knock sensor? Nothing has to be done to the wiring harness unless I wanted to remove the wires for rear o2's and crank position sensor?
Once the swap is complete, as far as scanning goes is it the same deal as '95 cars -- OBDI scanner with an OBDII connector?
The motor I picked up was a complete pull so I got the wiring harness, OBDI computer, starter, alternator, etc. I'm considering doing an OBDI conversion as well to make tuning easier. The '95 won't make it into the car for a while (probably a couple years) so I'm kind of considering doing the OBDI swap ahead of time as I've wanted to tune my car for a while however the aftermarket for OBDII LT1 tuning is pretty sparse.
I was thinking of sending my OBD1 PCM to Ion then having him set it up for my car as is. As far as the swap goes, it's simply plug and play? Just plug in the OBD1 PCM then drain the coolant and install the new knock sensor? Nothing has to be done to the wiring harness unless I wanted to remove the wires for rear o2's and crank position sensor?
Once the swap is complete, as far as scanning goes is it the same deal as '95 cars -- OBDI scanner with an OBDII connector?
Last edited by 6SpdLT1Z; 01-29-2014 at 03:59 PM.
01-29-2014, 04:44 PM
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Re: OBDII -> OBDI Conversion on '97 LT1
You can also have a resistor added to the OBD-1 PCM to allow you to interface it with the 100Kohm 96/97 knock sensor. But then you would have to swap the knock sensors when you got around to installing the 95 engine.
Harness pinouts are the same. You will also have an unused connection on the 97 harness for the EVAP system vacuum detection switch near the passenger side valve cover.
Rob/Shoebox has a 95 PCM wiring pinout list, with the differences between 95 and 96/97 shown in red:
4th Gen LT1 F-body Tech Articles
He also has the wiring diagrams for the 95 and 96/97 ALDL connectors, which appear to indicate that pin D30 is used on both PCM's and pin 9 on both ALDL connectors:
http://shbox.com/1/DLC_wiring.jpg
Harness pinouts are the same. You will also have an unused connection on the 97 harness for the EVAP system vacuum detection switch near the passenger side valve cover.
Rob/Shoebox has a 95 PCM wiring pinout list, with the differences between 95 and 96/97 shown in red:
4th Gen LT1 F-body Tech Articles
He also has the wiring diagrams for the 95 and 96/97 ALDL connectors, which appear to indicate that pin D30 is used on both PCM's and pin 9 on both ALDL connectors:
http://shbox.com/1/DLC_wiring.jpg
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