NH OBD2 engine swap
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On The Tree
Joined: Nov 2012
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From: Weare, NH
NH OBD2 engine swap Hello all,
Looking at purchasing a 96 Caprice, and at some point I'd like to swap an LS into it. What I'm worried about is passing the NH plug-in OBD2 inspection with the LS computer. For non-NH residents, the system works by the guy plugging in the inspection computer into the OBD2 port, inputting the cars VIN into the computer, then it links up and checks the computer functions.
I'd be doing the standard stuff, deleting rear o2, deleting auto trans codes (going T56), and other not needed extra stuff. I'll be building a plug-n-play engine harness for the car, so everything electrical will be 100% functioning. I just don't want to buy four O2 sensors, but if I have too, I will.
From the NH state inspection website:
Anyone here done an LS swap into a non-LS OBD2 vehicle in NH? Are the serial pins the same on the Caprice and LS diag ports?
Thanks
Looking at purchasing a 96 Caprice, and at some point I'd like to swap an LS into it. What I'm worried about is passing the NH plug-in OBD2 inspection with the LS computer. For non-NH residents, the system works by the guy plugging in the inspection computer into the OBD2 port, inputting the cars VIN into the computer, then it links up and checks the computer functions.
I'd be doing the standard stuff, deleting rear o2, deleting auto trans codes (going T56), and other not needed extra stuff. I'll be building a plug-n-play engine harness for the car, so everything electrical will be 100% functioning. I just don't want to buy four O2 sensors, but if I have too, I will.
From the NH state inspection website:
How the OBD System is Tested
The OBD system test consists of several individual checks. Failing any one of the tests will result in an overall failure of that vehicle for the emission portion of the NHOST inspection.
1. MIL Check During Key On, Engine Off Operation
This is checked manually by the mechanic. The Malfunction Indicator Light, or MIL, should illuminate when the ignition is in the Key On, Engine Off (KOEO) position, often labeled as the Run position. If your MIL light fails to light it could indicate that the OBD system is not functioning, that the MIL bulb is not working, or that the system wiring is damaged.
2. Diagnostic Link Connector Check
This check is also performed by the mechanic. The Diagnostic Link Connector (DLC) is the port into which the NHOST inspection unit connects when performing the OBD test. The port, which is standardized and required on all 1996 and newer passenger vehicles that have a gross vehicle weight rating (GVWR) of 8500 lbs or less, is usually located under the dashboard on the driver's side. If the DLC port has been cut out, stuffed behind something so it is inaccessible or has otherwise been damaged so that the inspection equipment cannot connect to it, the vehicle will fail the OBD test.
3. Communication with Vehicle
The NHOST inspection unit automatically performs this check, which simply ensures that the inspection equipment is able to read the OBD system monitors. If it is unable to properly communicate with the vehicle, there is a problem with the OBD connection or system that needs to be addressed.
4. Vehicle Readiness Check
This check tests to see if the vehicle has gone through the proper drive cycle(s) to be ready for testing. A drive cycle is a particular series of events that need to occur for the monitors to properly evaluate how the vehicle is performing. For example, part of a drive cycle might be driving at 40 mph for 5 minutes, idling for 15 seconds and driving in stop and go traffic for 15 minutes. Check your owner's manual. Each manufacturer has their own drive cycle and vehicle makes produced by the same manufacturer may even have some variation. Most people will complete the drive cycle for their vehicle in no more than three days just by using their normal driving routine. Vehicles that are only driven for short distances or at low speeds may take longer to complete their drive cycle and/or require special operation such as at higher speeds.
Issues with completed drive cycles prior to the NHOST inspection are typically only of concern when the OBD system has been "cleared" to remove previously recorded DTCs. This would be done when a previous problem was corrected and the mechanic cleared the OBD system after making the needed repairs so that the check engine light would no longer illuminate. Unless you have had recent work done that required this clearing, your monitors should all be ready. If there are monitors that are not ready, however, the vehicle will not pass the OBD test.
5. MIL Commanded On
This is an electronic check that has two purposes. First it is a deterrent against someone improperly tampering with the OBD system in an attempt to obtain a passing test when the vehicle has OBD defects. Second, if the MIL is commanded on and DTCs are present, it indicates a serious problem with the vehicle. If the MIL is commanded on for whatever reason, the vehicle will fail the OBD test.
6. MIL Light On While Engine Running
This test is a visual check performed by the mechanic if the NHOST inspection unit is unable to communicate with the vehicle as described above. It is used as a catch-all check in case the other above checks cannot be performed. If the MIL light is on while the engine is running, the vehicle will fail this check.
The OBD system test consists of several individual checks. Failing any one of the tests will result in an overall failure of that vehicle for the emission portion of the NHOST inspection.
1. MIL Check During Key On, Engine Off Operation
This is checked manually by the mechanic. The Malfunction Indicator Light, or MIL, should illuminate when the ignition is in the Key On, Engine Off (KOEO) position, often labeled as the Run position. If your MIL light fails to light it could indicate that the OBD system is not functioning, that the MIL bulb is not working, or that the system wiring is damaged.
2. Diagnostic Link Connector Check
This check is also performed by the mechanic. The Diagnostic Link Connector (DLC) is the port into which the NHOST inspection unit connects when performing the OBD test. The port, which is standardized and required on all 1996 and newer passenger vehicles that have a gross vehicle weight rating (GVWR) of 8500 lbs or less, is usually located under the dashboard on the driver's side. If the DLC port has been cut out, stuffed behind something so it is inaccessible or has otherwise been damaged so that the inspection equipment cannot connect to it, the vehicle will fail the OBD test.
3. Communication with Vehicle
The NHOST inspection unit automatically performs this check, which simply ensures that the inspection equipment is able to read the OBD system monitors. If it is unable to properly communicate with the vehicle, there is a problem with the OBD connection or system that needs to be addressed.
4. Vehicle Readiness Check
This check tests to see if the vehicle has gone through the proper drive cycle(s) to be ready for testing. A drive cycle is a particular series of events that need to occur for the monitors to properly evaluate how the vehicle is performing. For example, part of a drive cycle might be driving at 40 mph for 5 minutes, idling for 15 seconds and driving in stop and go traffic for 15 minutes. Check your owner's manual. Each manufacturer has their own drive cycle and vehicle makes produced by the same manufacturer may even have some variation. Most people will complete the drive cycle for their vehicle in no more than three days just by using their normal driving routine. Vehicles that are only driven for short distances or at low speeds may take longer to complete their drive cycle and/or require special operation such as at higher speeds.
Issues with completed drive cycles prior to the NHOST inspection are typically only of concern when the OBD system has been "cleared" to remove previously recorded DTCs. This would be done when a previous problem was corrected and the mechanic cleared the OBD system after making the needed repairs so that the check engine light would no longer illuminate. Unless you have had recent work done that required this clearing, your monitors should all be ready. If there are monitors that are not ready, however, the vehicle will not pass the OBD test.
5. MIL Commanded On
This is an electronic check that has two purposes. First it is a deterrent against someone improperly tampering with the OBD system in an attempt to obtain a passing test when the vehicle has OBD defects. Second, if the MIL is commanded on and DTCs are present, it indicates a serious problem with the vehicle. If the MIL is commanded on for whatever reason, the vehicle will fail the OBD test.
6. MIL Light On While Engine Running
This test is a visual check performed by the mechanic if the NHOST inspection unit is unable to communicate with the vehicle as described above. It is used as a catch-all check in case the other above checks cannot be performed. If the MIL light is on while the engine is running, the vehicle will fail this check.
Thanks
