Hondata

89 Civic
S300... serial 20723
LSvtec swap with gsr head, 240cc injectors, stock IM, stock exhaust manifold.

My question is can I use the switched power from the ecu to power both sides of the relay when adding an IAB solenoid to a p28 ecu? Or should I use a power circuit that's entirely separate from the ecu to power the solenoid... I can make a diagram if my question is unclear.

By switched power from the ecu I mean the same source that goes to injectors and other solenoids. B1 or A25 I believe...

You should use a different source...there is switched power in the fuse box under the dash on unused terminals.

Ok, thanks. Can you explain why it might be bad to use the IGP source?

So that it does not interfere witht the power to the ECU. It can cause interference due to the relays.

Alright then. Thanks again!

Different question since this thread is already here... Is it possible to calibrate the tach output? My stock EF tach is incorrect, or at least it does not agree with the Hondata. I haven't figured out how much the scale is off exactly.

There may be an internal adjustment inside the tach itself, but nothing ECU related.