Hondata

I have an 87 CRX with a D15A3 engine that I am trying to run with the S300. I have converted the engine to run a OBD1 Distributor, 4-Wire O2 sensor and a harness to fit OBD1 ECUs. The car does not have a VSS, ELD or IAC and has stock 190cc injectors.

I have a bone stock P28 and a P28/S300 (unmodified P28 basemap) and strangely they run the car very very differently.

Stock P28:
The car idles and runs, doesn't stall, but runs very poorly (as expected). ELD and Vtec codes as expected.

P28/S300:
The car won't idle unless the throttle is open slightly otherwise the throttle surges dramatically then dies. If the engine is revved it will stall as the engine revs down. ELD, Vtec codes (as expected) but also a cylinder sensor code when the engine is revved (not at idle).

I used the SManager to change injectors to 190, disabled the ELD check, Vtec check which cleared up those codes but the car won't idle like the stock P28 does.

I know it's a crazy setup but due to the rules I'm restricted buy this is what I have to work with.

First things that come to mind are Baro sensor and MAP sensor. However, that does not explain why the stock P28 works, and the S300 one doesn't.

I hate to be a post bumper but nobody can think of any reasons why the stock P28 and P28/S300 with stock basemap run so completely differently?

They are not exactly the same files. THe "stock" files provided have been modified to use the Hondata code.

I understand the files are not exactly the same but am I wrong in the assumption that a stock P28 and a P28/S300 with no changes should run just about the same?

My point is with the stock P28 all I needed to get the car running right is to adjust the fuel maps and eliminate codes for missing equipment.

The S300 was supposed to solve those few problems (which it can do) but I have gotten a different set of problems in exchange for no reasonable explanation in doing so.

My only assumption is that the S300 reads more/different data than the stock unit, which causes it to run different. Unfortunately I can't find any useful documentation on the difference between how the stock unit vs. s300 gathers data.