obd1 or obd2

[KApwr'd510]

I have 1995 KA24DE. When I got the engine I was told it was OBD1. The numbers on my ecu list as geing OBD 2. Was there a difference in the same year and what problems will I encounter if I use the wrong ecu? At the moment the engine seems to run fine except when coming to a stop after cruising down the road. It stutters and stumbles a bit. I also cannot get the fuel pump to run from the ecu (jumpered for now) as the ecu is not putting out any voltage for the pump relay and there is no output for the tach either. Any suggestions clues? I searched but did not find this particular problem.Thanks,Joe

[EZcheese15]

You have an OBD almost 2 ECU. In other words, it's OBD2, but not officially. Official OBD2 cars did not begin until 1996. However, there were *some* 1995 cars (and a few 1994) that are OBD2. The 240SX is one of them. You basically are running a beta version of OBD2 sorta. So yes, you are OBD2, but it is not the "full version" as 1996+ cars have. There may be a few OBD2 requirements there all not all there in the 1995.

But in any case, if you are swapping ECU's, you need to get one of the SAME year car regardless. There are emissions changes, fuel map adjustments, etc, in almost every year change.

[KApwr'd510]

That seem's reasonable. I'm thinking of swapping. I found someone that has a ecu with the same numbers as mine. I'm hoping it will take care of the problems I'm having with the fuel pump and tach. I also found that I am unable to retreive any codes from the ecu I have.Thanks for the info. Any clues as to why the ecu won't give any codes or power the fuel pump or give tach output.

[NISTECH]

The pin layout for the 95 and 96 are identical. You could use a 96 ecu in your car and it would run mostly normal. You would have codes galore though for all the sensors and actuators for your evap system as 95 did not use all the Evap obdII equipment. There is as Torry said a slightly different fuel map so you could run slightly richer as well.

As for your fuel pump issue. Your ECU does not power the relay , it grounds it. I would start looking for problems with the other three terminals at the relay. If you applied power to the terminal going to the computer from the relay you likely fried the driver that controls that ground in the ECM.