Hello everyone.
I have a 1990 crx si w a obd0 b16 swap. I am using the haspoort v-tec sub harness. This car has a power core high flow cat, and a dc 4-2-1 header with the 2 o2 sensors. I am using the sensors off a 1989 teg ls. I just got the car back on the road after a few years of sitting. I ran a few tanks of gas thru it, changed all the basics, oil, plugs, cap, rotor, etc. I failed my state emissions realy bad but it still drove great with no codes. I was taking a 2 hour trip and my check light came on. I pulled the carpet up and I am getting 2 fast flashes at the ECU. Someone told me to change both 02 sensors, so I did, I rest the ecu, and it came back. I know my wiring is correct. V-tec works great but the motor seems to be running kind of rich. Does anyone have any ideas? Is this a code 2?

 

Bump. Anyone?

 

Code 2 is the O2 sensor, check that.

 

Last night I bought 2 brand new o2's and replaced them, I also checked my wiring. Still same code.

 

Your O2 sensors are in the wrong location. It's running rich because of the code.
See below

https://honda-tech.com/zerothread?id=900501

The pic in that thread will help you to re-locate your sensors.

The DC headers were designed for ODB-1 and 2 cars.

 

My o2 bungs are just like in that pic, except the seconed o2 is just slightly farther down in the header. I had the bung welded in and it is exactley like that pic. Any other ideas?

 

I took the car to work today and the car runs great. I have no boging or hesitation. Half way to work the light comes on and I get the code 2. I am running out of ideas here.

 

Thats because thats when your car is fully warm. What you have to do is either somehow get the O2 sensor closer as the OEM one would be. Or pull the CEL bulb lol what ever works for you

 

The o2's are in the correct spots, the location I have is identical to that pic. I think I may of found my prob. I wanted to pull my plugs to see what they looked like ( to look for a lean or rich condition) my #1 and 2 spark plugs were completley submersed in oil and the wires where soaked. I have 2 bad spark plug wire gromets in my valve cover. Im thinking that the oil soaking in the spark plug wires etheir partialy grounded them out, or atleast reduced spark and I think this created a rich condition ( unburned fuel going out of the motor). I think then the computer tried to compensate and leaned it out. Every spark plug came out white. I thought right away this was from detination, but I have also run alot of cleaner thru the gas tank so that could be it to. Im going to install some new gromets, clean up the spark plug wires, and see what happens.

-Chris

 

Well that could be it, good luck and let me know how it goes

 

Ok. I pulled the plugs, cleaned them, cleaned all the oil out. Installed new spark plug gromets, valve cover gasket and ruber gomets under the nuts. I reset the ECU. Took it out on a ride for 15 min and the check engine came on, code 2. Tomorrow I am going to check continutiy of the wire from the ecu to the 02 to make sure I have a connection. What else could this be besides a broken connection?

 

Just double check that you switched the ecu wires for the O2 sensors. The only other thing is that you could run a new wire for each of the O2 sensors straight from them to the ecu, I ended up doing that, it just leaves wires in the original harness, make sure to cap them off so they dont mess up your computer. I had a problem with my car running super rich and it was throwing a code for knock sensor, so I got a vtec sub harness and put that in and then eventually found out that the person that wired up my dpfi->mpfi did the wiring at the ecu wrong and I fixed that and all better. Its probably something in the wiring just be happy your car isnt like mine. I had a coating of black unburned fuel on the back and was getting 6 mpg.

 

I am so confused!! I dont know what could be wrong. I just checked my wiring with a volt meter. I have continuity from the ecu to the o2 sensor. My sensor is brand new, my wiring is good, what else could be wrong? I followed hasports directions for the wiring. By the way, I have a Pw0 ecu. It reads 37820-pw0 000 250-300391 MA.
Im leaving for NJ today and wont be able to work on my car tull sunday. Keep the ideas coming.

 

I just checked again and my 2nd o2 goes right into c8 on the ecu, I looked at my hasport directions and the pic on that link you sent, the wire is in c8. I am clueless. I know the code 2 is for the o2 but im wondering what makes it triger. My understanding was the code was just for a failue in the o2 circut. What im saying is a incroect fuel/air mixture would not cause this light correct? It has to be a problem in the citrut somewhere. Everything seems good and I am stuck.

 

Does any one have any ideas?

 

Check your timing, make sure that it hasnt skipped a tooth, that could throw it off. Or you can check the fuel pressure, you may not be getting enough fuel pressure. Or check the injectors, they may not be pushing the correct amount of fuel in. Just trouble shoot you'll get it eventually. It only took me like 7 months to get my car correct.

 

So I just switched my o2 wires, I have my primary o2 wire going thru hasports subharness wire to c8 and I have my secondary o2 wire going to the factory crx si harness plug. It seems to idle better but the code is still here. What else could be causing this code 2? Im going to check continuity from the facotyr o2 plug to pin c16, but other then that i cant think of anything. Any other ideas?

 

My wire from my o2 sensor to c16 on the ecu is good. I talked to Hasport today and what they think is wrong is my header. I have a DC header that 1-4 go to a collector then I have a o2 right after the header then 2 and 3 go to a collector and I have my 2nd o2 a little after that. They said the o2 needs to be in the single collector of cylinder 3 and 4about 6 inches after the head. They think my o2 is not heating up from being after the collector. Does this sound right? Has anyone had a problem like mine with o2's after the collectors?

-Chris

 

its not the o2 sensor, forget about that. the code is o2 sensor 'or its circuitry and readings' right. if its running rich, the o2 sensor is letting the ecu know that there is too much crude petro passing through the headers. the problem is running rich (which would explain you not passing the state requirements.). if its not giving you a code other than the o2, you have a problem with the mechanical side of the engine. check the valve adjustment shich can cause an incorrect operation of the chamber effect, also check the timing to see if its right, check for air leaks on your intake system. check for compression on your engine. if all fails try a different ecu.

 

Did a compression check tonight. cyl 1=215 cyl 2=210 cyl 3=211 cyl 4-213. I also did an induction cleaning. No diffrence. Ill check my valve clearence tomorrow. Thanks for the reply. So you think my o2 itself is fine and not to low in the header? Im about to drop the header and weld a new bung in if I need to.

-Chris

 

Hey, dumb question but you know how you said that its my motor running ritch and not the bad sensor? When I switched the 2 o2 wires I still got a code for 2nd o2. In theory, when I swaped the c8 and c 16 wouldent the code of changed to a code 1 if it was indeed that cylinder not running corectly, because I switched o2's?

 

THAT WOULD BE IRRELEVENT. AND BTW ARE U CLEARING THE CODES BEFORE YOU SWAP CABLES....THEY DONT RESET BY THEMSELVES. plus, the o2 works with the positioning of the cam and the exhaust outlet it corresponds to. its still saying the 3rd or 4th piston is running rich so therefore your air leak might be between the 3rd or 4th inlet from the intake mani.

 

When I first read this I thought to myself, "His whole swap is throwing a code?"

ok, sorry..... back to thread....

 

I dident think it would be irrelevent, thats why I asked. Of course I am reseting the ecu each time, pulled the fuse for 30 seconeds. I understand what you are saying, But, you have the 2 wires, 1 goes to bank 1 one goes to bank 2, right now I have the code for the seconed one, if you switch the feed wires how would that not change anything? Im going to check the intake mani for leaks tonight. I dont think thats the case but ill check. Keep in mind the motor runs great with no detnonation or hesitaion and a perfect idle at 1,000rpm.

 

i understand that (to simplify what i previously said) but some the ecu works as a web of information. if another sensor detects that the last two cylinders where working incorrectly then it would throw you a code for the o2 sensor that is supposed to be regulating that cylinder. so its not the 02 sending that message, its letting the ecu know that a different sensor is detecting richness in fuel and the cause could be the o2 sensor assigned to that cylinder because the o2 usually tells the ecu to give it more fuel or less. therefor if a sensor is saying 'cylinder 4 is 'eating too much,' o2 sensor # 2 is the prime suspect in the 'crime' but as like in the legal system, theres a prime suspect and 100's of secondaries.