Ok i jus finished swapping a JDM d15b into my 1995 EX automatic. I used the d16z6 wiring harness and ECU. Now the car is running extremely rich at idle but it'll run pretty stoich during crusing. I checked my 02 voltage and it's about 912mV (aka rich as hell). I checked the 02 for proper operation and it works fine. Basically what will happen is after firing the car up it'll drive fine up untill a completely random point. Then the car, off a stand still, will bog down really bad. My RPMs will drop to about 200 300 or so. If i floor it the car will just sit there for about 30 secs slowly climb up the Rs and then start moving. I have no idea what's causeing this. Any help would be great

 

well
you're running 1.6 Fuel Maps for a 1.5 but this wouldn't cause your prob

I'm guessing it's the 02 sensor

If you're running P28 ECU, then you better be running the exh mani with the o2 sensor located on the bottom (OEM or aftermarket)

If you're running the JDM p08 ECU, run the Header with the 02 sensor closer to the exh ports

 

I've got a DC header so the O2 is mounted right before the cat. I'm pretty sure the O2 is working properly becuase voltage will drop if i create a lean condition but then it'll richin right back up.

 

so which ECU are u running?

 

as it says in the top post i'm using the d16z6 ecu and harness

 

I have a d15b running with a p28 ecu too, without any problems. I would check your map sensor, and maybe try swapping it out from ur old engine.

 

Are you using a wideband O2 sensor? because if you arent, then the voltage you are reading is not a good indication of how rich or lean you are running, it is more like an on/off switch at 14.7 af ratio. If you want to know how rich you are running, you need to either buy a wideband, or take it to a dyno facility and use the one there.

 

umm I think a wideband would be lil too much for mostly stock d15b. Seeing as how i haven't really altered my fuel delivery (electronic or mechanical) so that it would push the motor leaner or richer than the factory equipment can take it. So for a stock motor I'd think a stock O2 would be a pretty good indicator of weither I was running rich or not. O2 voltage is coming out at 912mV at idle. Meaning rich. If I was running stoich it would probably register somewhere around .450mV which would indicate around a 14.7 A/F ratio. I known the O2 is working correctly because if i make a Vac leak to create a temporary lean condition voltage will drop than go back up to 912mV.

 

You may be running rich, but what I am saying is that you have no idea of how rich you are running. You could be running just slightly rich, like 14/1, or you could be running very rich. The only way to tell is to use a wideband O2 sensor. If you really want it running a perfect A/F ratio, then you should take it to a dyno that has a wideband gauge that you can use. Otherwise, it is probably not running that rich if your gas mileage hasnt dramatically dropped.