eh2+b18c1=usdm sleeper

are the IABs different in the gsrs by year..iwas told that the 94-97 or 98 had negetive polarity to activate them and the 99-00 needed positive polarity for them to engage...so whats the deal? i have skunk2 p28 running a stock gsr manifold, and i wanted to know if they were open or closed all the time..everone tells me i should lose low and gain high..but it fells like i have no highend. any hrelp?

VTECVillain

I don't think it's the sensor itself that's different, but rather the ecu controlling it. I have a 99 B18C1 with a 95 P72 ecu so the wiring for the secondaries is matched to the ecu. It's been so long since I installed it, but I do remember that the OBDI to OBDII have different polarity for that sensor. I'll have to check the Helms to let you know which is which. If you are running the P28 ecu you should run the Skunk2 R manifold which eliminates the secondaries all together.

92sleepR

Polarity might not be the best way to describe it but here's the deal, On OBD 1 cars the IAB signal from the ECU is a ground. if you test the second wire (the one that isn't connected to the ECU) at the solenoid you will find that it's +12v switched with the ignition. On OBD 2 cars, 1996 and later, the signal from the ECU is a +12v and the second wire at the solenoid is ground. I don't know why Honda did this but they must have had their reasons.

Anyway, it's easy to get an OBD 1 ECU to work with an OBD2 harness, just connect the second IAB solenoid wire to +12v. The wire at pin A17 at the ECU is the same regardless.

Mike