Need the overall collective knowledge of the forum to source this IC in the 1995-1996 engine ECU. It is the flat inline IC with the labeled X4HT BX8371 9447 right in the middle of the pic.
This IC does not appear to be in the NSX 91-94 ECU but could be in the post 96 NSX ECU, or in other Honda/Acura ECUs from the same era. Background on why I need this chip below.
If you search the forum, you will see I have been trying to get a 95-96 MT NSX ECU for a while. I purchased a 95 MT NSX and it was throwing P0141 and P0161 codes. The car came from Colorado and had a clever cats delete (it had the cats but the cats were hollow and the CEL light bulb was removed). I need a functioning emissions system to pass CA SMOG so went about gathering up a complete emissions system from ebay, offerup and the forum. After putting the emissions back to stock, the P0141 and P0161 codes remained. Went through the factory service manual checks and the only thing left to do was to replace with a known working ECU. Sourcing a 95/96 ECU is difficult given there were slightly over 1,000 95/96 delivered and I am not sure how many are left. I was eventually able to get a 96 auto ECU from ebay and a 95/96 MT ECU from a member on this forum.
The 96 auto ECU is identical to the MT ECU in all ways except for additional components to communicate with the auto transmission controller and different codes to do that. When I plugged in the auto ECU, the engine fires right up and the only code was P1607 (communication fail to the auto transmission controller). This gave me hope and I did some surgery to remove one of the auto ECU CPU (the one with a different version label than the MT CPU) and replaced it with the MT CPU (this involved desoldering a 80+ pin surface mount chip and putting a socket on the board, I have pics if anyone is interested). Again I was able to fire up the engine with the modified ECU and the P1607 code went away, replaced by a different code for ECU side A failure. This is probably due to the CPU pulling code from an eeprom somewhere else on the board. At this point, I gave up on the surgery idea and put the MT chip back into the MT ECU.
The other MT ECU I got from a forum member also threw two O2 sensor codes (P0141 and P0155). P0141, P0155, P0166 are all related to the O2 heater circuit which run on batter voltage. I suspect the many issues people had with 95/96 O2 sensors were probably actually caused by the ECU - therefore the extended warranty. In desperation I systematically moved good components from the AT ECU to the MT ECU. I had hints on where to start by tracing the pins that connect to the Port A connector that drove the O2 heater circuits. By replacing the IC at the top of this posting, I was able to fix the P0141 code. Replacing additional chips around the same area fixed the other code. I can source the other chips but cannot find the big one anywhere.
I would like to source the BX8371 IC to help other 95/96 NSX owners avoid the difficulty of getting a working ECU. I think the best bet would be finding the same IC in other engine ECUs that are much cheaper. BX8371 appears to be discrete components soldered to a board and then encapsulated - a long way to say it is not a logic chip that is more widely used.
Drop me a line if anyone can help me help other members keep their CEL off.
This IC does not appear to be in the NSX 91-94 ECU but could be in the post 96 NSX ECU, or in other Honda/Acura ECUs from the same era. Background on why I need this chip below.
If you search the forum, you will see I have been trying to get a 95-96 MT NSX ECU for a while. I purchased a 95 MT NSX and it was throwing P0141 and P0161 codes. The car came from Colorado and had a clever cats delete (it had the cats but the cats were hollow and the CEL light bulb was removed). I need a functioning emissions system to pass CA SMOG so went about gathering up a complete emissions system from ebay, offerup and the forum. After putting the emissions back to stock, the P0141 and P0161 codes remained. Went through the factory service manual checks and the only thing left to do was to replace with a known working ECU. Sourcing a 95/96 ECU is difficult given there were slightly over 1,000 95/96 delivered and I am not sure how many are left. I was eventually able to get a 96 auto ECU from ebay and a 95/96 MT ECU from a member on this forum.
The 96 auto ECU is identical to the MT ECU in all ways except for additional components to communicate with the auto transmission controller and different codes to do that. When I plugged in the auto ECU, the engine fires right up and the only code was P1607 (communication fail to the auto transmission controller). This gave me hope and I did some surgery to remove one of the auto ECU CPU (the one with a different version label than the MT CPU) and replaced it with the MT CPU (this involved desoldering a 80+ pin surface mount chip and putting a socket on the board, I have pics if anyone is interested). Again I was able to fire up the engine with the modified ECU and the P1607 code went away, replaced by a different code for ECU side A failure. This is probably due to the CPU pulling code from an eeprom somewhere else on the board. At this point, I gave up on the surgery idea and put the MT chip back into the MT ECU.
The other MT ECU I got from a forum member also threw two O2 sensor codes (P0141 and P0155). P0141, P0155, P0166 are all related to the O2 heater circuit which run on batter voltage. I suspect the many issues people had with 95/96 O2 sensors were probably actually caused by the ECU - therefore the extended warranty. In desperation I systematically moved good components from the AT ECU to the MT ECU. I had hints on where to start by tracing the pins that connect to the Port A connector that drove the O2 heater circuits. By replacing the IC at the top of this posting, I was able to fix the P0141 code. Replacing additional chips around the same area fixed the other code. I can source the other chips but cannot find the big one anywhere.
I would like to source the BX8371 IC to help other 95/96 NSX owners avoid the difficulty of getting a working ECU. I think the best bet would be finding the same IC in other engine ECUs that are much cheaper. BX8371 appears to be discrete components soldered to a board and then encapsulated - a long way to say it is not a logic chip that is more widely used.
Drop me a line if anyone can help me help other members keep their CEL off.