I swapped the gsr into my ek on the weekend , Its running super rich and I am getting a couple CEL's including a 41, Primary oxygen sensor. I am running a p72 obd1 ecu , stock obd2 engine harness and obd1 gsr. I have the secondary o2 harness unplugged and the primary is hooked up running into my header. The o2 was bought in the summer and its NGK, getting horrible fuel mileage and car is idling crappy , please advise
thanks

 

your ECU is reading that there's o2 sensor not plugged in (had this happen to me), i say do what i did and get a socketed ECU and a crome tuned chip from phearable.net.

 

Is there no pinning or unpinning in the harness I can do to make it read the current o2? I like the piece of mind my ecu is a virgin and would prefer to keep it stock for the time being

 

List ALL CELs please.

 

Code 20 Electronic load detector (ELD)
Code 21 Variable Valve Timing and Valve Lift Solenoid - VTEC solenoid check
Code 41 Oxygen sensor heater


I used my D series alt with the hybrid upper bracket trick, not sure if that hs anything to do with the ELD fault.

My vtec is working well and kicks hard so I am not sure about the code 21 fault

 

What ECU are you running? This thread covers your 2nd and 3rd codes diagnosis:

https://honda-tech.com/forums/hybrid-engine-swaps-18/%5Bfaq%5D-%22my-vtec-doesnt-work%22-1812135/

 

He is running the correct ECU, a P72 OBD1. Fist off make sure you have the O2 plugged into the correct plug on the harness, in DX and LX modles the 02 plugs are right by each other and are easily swapped. IF this is not the case them try another O2 sensor, you can use either of the 2 from the D16 both are 4 wire sensors. I would have used the GSR alt because you are running a GSR motor and a GSR ECU, I would use a newer OBD2 alt though. If you have a DX or LX then you would need to run wiring for Vtec, really easy 2 wires to the ECU and a ground to the block. FF-squad will have all your wiring swap needs.

 

7.5A dash fuse 15 may be blown. Check it.

 

Fuses are all good , just checked the whole panel

 

What voltage to body ground do you measure at each top test tab of installed 7.5A fuse 15 with the key in ON(II)? Click the fuses link in my signature.