Car info:
-92 CX hatch
-b16a
-stock p28 ecu
-LS b18b engine harness (ran my own wires for vtec)

Problem:
Only 1 fault stored - code 41 - heated oxygen sensor heater

Start up the car has a very low idle 300-400rpm, but drives fine minus vtec engaging sometimes and sometimes it won't. If I beat on it and let it idle it sometimes it will surge idle, sometimes it will idle HIGH 2000-2500rpm and sometimes it will idle normal 800rpm.
Also it wont start randomly from time to time, it will just crank and crank and crank.

What I've tried:
-While the car was surge idling I unplugging all sensors 1 at a time to see if anything changed the only one to change anything was the iacv and it idled normal.
-All grounds are perfect .02-.04ohms
-Plugged the hole inside the TB to the iacv while surge idling it dropped to a perfect idle but do it on a low idle and it will stall.
-My TB doesn't have a fast idle valve, so I cant adjust that.


Anybody have any ideas or something I can try. I have a multimeter and plenty of tools, I just don't know where to go from here.

Thanks guys!!!

 

night bump.

 

-you might need a new o2 sensor or check the wiring
-you need an obd1 throttle body because that comes with fast thermal valve and at start up it won't idle low
-you need an obd1 b16 ecu or get your p28 chipped with a b16 basemap

 

First off thanks for the reply.
-Checking the O2 wiring/ sensor is the first thing on my agenda in the morning.
-Sorry I should have said I JUST rebuild this motor and put new Nippon pr3 pistons, jdm gsr cams and a catch can set up getting ready for boost. THAT being said the TB/ intake manifold are stock to that motor and worked perfect before the rebuild.
-Also, I know I should run a chipped ecu or a stock b16 ecu but the car ran, drove and idled fine for well over a year with no issues. I planned on boosting it so I didn't bother getting it chipped and tuned twice.

 

stock p28 ON A b16? wowsers...totally wrong ignition and fuel maps! get a p30 man seriously

p28 is vtec at 4800 and cut off at 7200...why would you drive a dohc vtec engine around for a year like that?? :confused: