retroshark
Well-Known Member
OK, so here is another really useful writeup (in my humble oppinion) about how to convert the accords OBD computer system from II to I
now, before you go on I must tell you, I personally have experienced problems possibly reguarding this conversion BUT have yet to prove that they were caused by the conversion... so, do this ONLY if you are willing to deal with a lot of wiring and possible problems deppending on what else you do to your car while converting to OBDI
now to start off, the bennefit of converting to OBDI is very simple... TUNING.
you can run an AEM EMS or a Piggyback system such as an emanage without converting anything but its a matter of prefference really.
To begin, i will include everything you need to convert the system. dont argue with me that some of this stuff may seem stupid because i promise you, it is the easiest way i have found to successfully convert to obd1 both electronicly and mechanicly.
OBDI ECU (P28 is what i used)
OBDII - OBDI conversion harness
OBDI honda resistor box
OBDI injector clips that match your injectors
Injectors from an OBDI car (easiest i found was a set of DSM injectors)
OBD1 F22 Intake manifold, complete with all sensors
OBD1 IACV (if not included with manifold)
F22 Fuel rail for manifold
OBDI IACV plug from wiring harness
98-02 Accord Haynes manual
92-97 Accord Haynes manual (for refference)
now, the reason you need to get the f22 intake manifold is because there are currently no manifold adapter plates for converting to an obd1 IACV, and no, the blacktrax iacv plate does not fit on the f23 manifold correctly.
the manifold does bolt on correctly, so dont worry, you just need to make sure you get everything hooked up right (i have an EGR blockoff plate so i didnt need to install that)
there are no real steps to this, its more of a plug and play affair really. I reccomend both accord haynes manuals because there is wiring that may be different and they both have wiring diagrams with wire colors. for instance, you need to find what wire is which for the IACV, as you now will run a 2 wire IACV instead of a 3 wire (3rd wire on the obdII is for resistance, other two are + and -)
now, to void any myths that are out there, you DO NOT NEED TO CONVERT TO AN OBDI DISTRIBUTER in order to make this work. my car runs fine without it and it was never an issue.
now another word of warning, you cannot pass emissions after doing this switch on your car, so be aware of this, and dont blame me if you cant find somoene to pass you or if you still want your car to be legal, because technically, this is not legal.
once you have everything hooked up, you do need to make sure that your ecu you use is chipped//socketed so that you can take advantage of the new system. also, get a local tuner to burn your engine basemap to an emprom chip or the ECU will not let teh car start up. make sure that if you plan on using vtec, you get an ecu that has the appropriate setup. some ECUS prevent vtec from being used.
ok, so with that info, you should be pretty much good to go. as i said before, this is all the info that is out there, written by someone who has done the conversion on the 6th gen, and this is SPECIFICALLY for the 6th Gen ONLY.
the following is the ecu pinout diagrams for the accord ECU compared to the OBDI P28 ecu. use it for troubleshooting possible bad wiring on your conversion harness, and also for general refference. this took me a while to make, so if you plan on using it, just ask me first. as far as i know, its correct, but report any issues with it to me!
thanks a lot guys and enjoy this, i hope it helps you guys out!
now, before you go on I must tell you, I personally have experienced problems possibly reguarding this conversion BUT have yet to prove that they were caused by the conversion... so, do this ONLY if you are willing to deal with a lot of wiring and possible problems deppending on what else you do to your car while converting to OBDI
now to start off, the bennefit of converting to OBDI is very simple... TUNING.
you can run an AEM EMS or a Piggyback system such as an emanage without converting anything but its a matter of prefference really.
To begin, i will include everything you need to convert the system. dont argue with me that some of this stuff may seem stupid because i promise you, it is the easiest way i have found to successfully convert to obd1 both electronicly and mechanicly.
OBDI ECU (P28 is what i used)
OBDII - OBDI conversion harness
OBDI honda resistor box
OBDI injector clips that match your injectors
Injectors from an OBDI car (easiest i found was a set of DSM injectors)
OBD1 F22 Intake manifold, complete with all sensors
OBD1 IACV (if not included with manifold)
F22 Fuel rail for manifold
OBDI IACV plug from wiring harness
98-02 Accord Haynes manual
92-97 Accord Haynes manual (for refference)
now, the reason you need to get the f22 intake manifold is because there are currently no manifold adapter plates for converting to an obd1 IACV, and no, the blacktrax iacv plate does not fit on the f23 manifold correctly.
the manifold does bolt on correctly, so dont worry, you just need to make sure you get everything hooked up right (i have an EGR blockoff plate so i didnt need to install that)
there are no real steps to this, its more of a plug and play affair really. I reccomend both accord haynes manuals because there is wiring that may be different and they both have wiring diagrams with wire colors. for instance, you need to find what wire is which for the IACV, as you now will run a 2 wire IACV instead of a 3 wire (3rd wire on the obdII is for resistance, other two are + and -)
now, to void any myths that are out there, you DO NOT NEED TO CONVERT TO AN OBDI DISTRIBUTER in order to make this work. my car runs fine without it and it was never an issue.
now another word of warning, you cannot pass emissions after doing this switch on your car, so be aware of this, and dont blame me if you cant find somoene to pass you or if you still want your car to be legal, because technically, this is not legal.
once you have everything hooked up, you do need to make sure that your ecu you use is chipped//socketed so that you can take advantage of the new system. also, get a local tuner to burn your engine basemap to an emprom chip or the ECU will not let teh car start up. make sure that if you plan on using vtec, you get an ecu that has the appropriate setup. some ECUS prevent vtec from being used.
ok, so with that info, you should be pretty much good to go. as i said before, this is all the info that is out there, written by someone who has done the conversion on the 6th gen, and this is SPECIFICALLY for the 6th Gen ONLY.
the following is the ecu pinout diagrams for the accord ECU compared to the OBDI P28 ecu. use it for troubleshooting possible bad wiring on your conversion harness, and also for general refference. this took me a while to make, so if you plan on using it, just ask me first. as far as i know, its correct, but report any issues with it to me!
thanks a lot guys and enjoy this, i hope it helps you guys out!
