im currently doing a obd1 gsr swap in a 99 civic.. the motor was in and running but now i keep blowing up ECU's the only conversion that i had to do was obd2-1 distributor and the IAC 3wire to 2 wire... the funny thing is the only ecu that doesnt throw code 0 is an OBD1 usdm accord non-vtec ECU.... any suggestions

 

you could switch back to the obd2 distributor because the obd1&2 are the same. also who did the obd2 - obd1 conversion harness for the ecu? what codes are you getting on the ecu?

 

im using a skunk 2 harness and before the **** hit the fan so to speak i was throwing IAC, crank angle and map but i fixed all of those...

 

and now it is frying the ecus?

 

throwing code 0 on a p28 and a prelude v-tec ecu

 

it was running fine until we started messing around with the conversion harness.. i was throwing map code so we decided after playing with the wires to run them straight to the ECU and ever since then its been screwed

 

well in my experience the map the tps and the PA sensor all run off the same Pos(+) feed wire is there a chance that the wire you disconnected is shorting to ground?

 

but why would that not fry a non vtec ecu

 

if ti is shorted to ground it would fry the ecu because you are letting an unlimited amount of current pass through the ecu and the ecu does not like that one bit. the non vtec ecu still uses the map tps and pa sensors or are you saying that the non vtec ecu does not fry but the vtec ones do?

 

non vtec ecu does not fry and vtec ecus do

 

well do you have the facotry manual to check pinouts? also check to see if the oil press switch for the vtec has continuity with engine off. it should not. the wiring also could have become disturbed when doing the direct wiring for the map. at this point there could be many possibilities to this problem what would be the best is what is uncommon between the two ecus, knock, vtec solenoid, vtec oil pressure, crank fluctuation sensor(mounted behind the harmonic balancer/crank pully), fuel tank press, I mean there are a lot of wires in an obd2 system that are not there on the obd1 and also between vtec and non vtec.