1995 Civic EX coupe with JDM B20b block, Integra LS head, P75 Intake, GSR Throttle body. Currently has P75 OBD1 ECU. '95 Civic wiring harness. Previous owner did all swaps. I purchased it five months ago. Stock automatic transmission has been/is converted to an Integra LS manual 5-speed.

Engine has a hunting idle since purchase. I recently depowered the steering rack and now experiencing stalling and lean idle issue. I'm getting help for the lean issue on a another forum from a long time Honda dealer machanic. Also, I have a Hondash OBD1 bluetooth scanner and app to view live data with. We're still narrowing down possibilties and the ECU is one of them. The person who sold it to me is good guy, straightforward and always answers any questions I have about to this day.

My question is what ECU or ECU + tune combination is best for my setup? Seems to me if it had a hunting (without stalling) idle issue since before I purchased it ..then maybe it's related to the ECU. When I say hunting idle it idles around 700 to 750 rpms (no load) for the majority of the time but then it will drop to around 300 rpms for a few sceconds and then return to 700/750. It does this sporadically but consistently enough to know it's not normal. When it drops it in idle I feel as it's searching for a basemap but can't find one. This and now the current stalling a idle issue leads me to the P75 ECU may not be idle for it?

Reading through info online there seems to be mixed answers...some say P28 (obd2) + Hondata 300 chipped and tuned. Others say OBD1 p73 itr map is best. The previous owner told me it has never been tuned so, maybe that's where the issue lies? All suggestions appreciated.
Related read: ecu for b20/vtec | HondaSwap

 

Neil Sutton can diagnose and tune an ECU been doing it for a long time

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