OBD2 to OBD1 conversion issue
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I have a minor issue that could be many different things, so I decided to ask before I started messing with the many different variables.
I recently bought a P72 OBD1 ECU and had someone make me a conversion harness so I could install it in my 96 GSR. I installed it and when I started the engine, it immediately threw a CEL. Checked the code and it was throttle position sensor.
Now my question is: What could be the problem here? I have the Greddy E-manage hooked up to my OBD2 ecu and that may have triggered the CEL with the new ECU, it could be the harness, or it could be the ECU. I am planning on chipping out the ECU, but I just wanted to try it out to see if it worked and the harness worked. I want to get rid of the E-manage, so I am thinking that I will reinstall the provided blue box with the turbo and get everything back as simple as possible before I try again.
I have one other question. I was going to use uberdata and I was having issues accessing certain parts of the site. Does someone have an updated site or a working link to the site?
I recently bought a P72 OBD1 ECU and had someone make me a conversion harness so I could install it in my 96 GSR. I installed it and when I started the engine, it immediately threw a CEL. Checked the code and it was throttle position sensor.
Now my question is: What could be the problem here? I have the Greddy E-manage hooked up to my OBD2 ecu and that may have triggered the CEL with the new ECU, it could be the harness, or it could be the ECU. I am planning on chipping out the ECU, but I just wanted to try it out to see if it worked and the harness worked. I want to get rid of the E-manage, so I am thinking that I will reinstall the provided blue box with the turbo and get everything back as simple as possible before I try again.
I have one other question. I was going to use uberdata and I was having issues accessing certain parts of the site. Does someone have an updated site or a working link to the site?
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So I need to switch to an OBD1 dizzy for the conversion? It works perfectly fine with the OBD2 computer hooked up and I have never heard that you have to convert anything besides the computer and wiring harness to run an OBD1 computer on an OBD2 car.
no, the only thing different between the two dizzy's is the actual plug on the dizzy which is made for your wire harness, not your ecu. Anyhow, how reputable is this person who made the wireharness for you, if i were you i would take it back and say that its throwing a tps code, recheck all of the connection please. After that, if the problem still exists, check the ecu. Take the cover off and look for a chip, just to be sure that it is not chipped. If no chip, check the voltage on the tps, I am not sure what the volts should read at idle, i think its something like 14, if it is correct, send the ecu back, if they wont take it back, sell and buy from a reputable person next time.
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I talked to the guy about the TPS code and he had me check the wiring and it all checked out fine. I have a strong possibility that it was throwing that code because of the E-manage that I had hooked up. I removed it last weekend, so I will try the harness again this weekend and see if it does the same thing. Then my guess is that it would have to be the ECU.
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So I plugged in the ECU again today since the Emanage is off and it is still throwing codes and having a very lopey idle. It isn't just throwing tps but also ect sensor and iat sensor codes as well. Does anyone know where I can find a pinout of a P72 OBD2 ECU? I want to compare it to a P72 OBDI pinout and see if the harness is wired properly. Even if it is bad, I want to fix it since the quality is good and the price was right.
well if the ecu is bad, send it back. there is no fixing a ecu that is fawked. I dont have a pinout for either ecu, but i bet you can find one at hondaswap.com or hybridgarage.com. both are very reputable sites, have fun.
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My money is on the harness at this point. I took a quick look at the wiring and it looks off. I don't know by how much but the wires are definitely in the right place. I just want to fix the harness since I have it all right here and I paid good money for it. I found the OBD1 pinout on hybridgarage.com but I am still lacking the OBD2a pinout. :thinking:
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Found a good site:
http://www.hasport.com/Tech/Wring/Co...0OBD2-OBD1.htm
I don't know how correct this is because it doesn't specify for which ECU it is converting.
http://www.hasport.com/Tech/Wring/Co...0OBD2-OBD1.htm
I don't know how correct this is because it doesn't specify for which ECU it is converting.


