i was just reading on hondaswap.com a tech article on swap 101's, it stated " all 1991 and earlier model civics are OBD0, which means they utilize no oxygen sensors, OBD1 and OBD2 which use oxygen sensors are 92 and up" my d16a6 has a 2 wire oxygen sensor on the lower part of the exhaust header, so how is this statement true? and can someone who knows alot about 88-91 civics si's pm me, i have a few engine/transmission related questions i want to ask (nobody responded to my last post, so maybe ill get a response through pm)

 

statement is not true...obd0 do use O2 sensors

 

yes, they do use o2 sensors, they just dont rely on them for complete engine control......and they are not as controlling as obd1-2 o2 sensors, remove an o2 sensor from an obd1+ vehicle with a stock ecu and the car goes into an open loop and runs like shit.......

 

ODBO - Uses O2, but does not rely on them
OBD1 - Utilizes 1 main O2 Sensor
ODB2 - Utilizes 1 Front (Bank1) and 1 Rear (Bank2) O2 Sensors, they swtiched to do this because of the federal regulations with ODB2

 

ok gotcha, i thought that is the way it worked, but saw that post and was like wtf... so anyone know about transmissions? when i am driving normal my car seems to shift fine, but the clutch doesnt seem like its engaging all the way, and pedal feels spongy, when i am 'accelerating hard' every gear grinds when i shift, would this be the clutch, or the transmission going or being bad?

 

if the pedal feels spongy you need to bleed your clutch system. chances are you have air in it. having air in it will not allow full pressure to build up and the clutch will not always fully disengage - which is why you are sometimes grinding...

 

if the car is a 91 and below civic,it has a cable transsmission and if the clutch feels spongy you might need to adjust the clutch or replace the clutch cable, and if its a 92 and up civic, exactly what sk8rmike said.......

 

ok, i will look in the haynes book and see if it says anything about adjusting, ive always had hydro trannys before this one, except on my bikes, those i can adjust... so i will give a shot on the next nice day see what that does.... but i just wondered another thing today... the block is stamped d16a6, the head is stamped a9b1301111 and pm3-8 , the ecu is a pm6? i know the engine block came in Si's, but what about the head and ecu??i havent heard much about the numbers on these and im just trying to figure out what the guy before me has done before i go trying to fix things. that might not need fixed, or might need to be done away with all together.

 

pm6 is a 88-91 si ecu, d16a6 is a 88-91 si engine block, and pm3-8 is a 88-91 si cylinder head.

 

thanks.... i have a choice to buy a whole sohc non vtec engine and trans for 650, or a good trans for 100 and a y8 vtec head with all sensors and vtec solenoid for 80..... so im just considering what i want to do... i wont know what condition my bottom end is in until i am ready to pull it out, its a daily driver too, so i cant just go out and do it, i kind of have to plan in advance on this one, any way to check the bottom end for problems without pulling out the head? or could i take it to a shop and have it quickly inspected for problems or is this just something i have to hope for the best with?