Did the search and the google search and didn't find what i'm looking to ask.

2000 DX swapped with a b16a2 (full swap over still using obd2b)
USDM ecu
dx fuel pump
dx fuel pressure regulator
primary o2 sensor wire lengthened to meet with the sensor

so i'm getting code p0131 and it's preventing vtec to kick in
cleared the code and it'll just come right back up in about 5 mins.

here are what I find that could be the issues
1. possible ecu issue (can switch ecu with a working ecu)
2. possible fuel system running too low of pressure and change pump and regulator
3. possible exhaust leak from the header (stock) between the main and pipe A, or possible leak between pipe A and cat
4. possible that both o2 sensors are bad?

anybody else run into these issues when doing the b16 swap?

 

P0131 Primary Heated Oxygen Sensor (Primary HO2S) (Sensor 1) Circuit Low Voltage

wiring is either wrong or the sensor is bad and if it came back that fast the wiring is wrong usually

 

Are you using the correct ECU for the engine? If so, start by measuring the fuel pressure.

I don't think an exhaust leak or a faulty secondary O2 sensor would throw P0131.

 

yes i am using the correct ECU. It was given to me by a friend with a b16a2 who had 2 ecu's.

I was thinking fuel pressure and the fuel regulator since they are both from my dx.

 

feeling that the car is running super lean.

going to swap out the fuel pump tonight to see if that helps.

 

Do some diagnostics rather than replace parts at random.

 

I have a scan tool and can clear to the code while driving, but here is some additional info.
Cleared code when car is cold, and light will not turn on immediately only after the car is warm and I’m on the freeway. At that time if I clear the code, it’ll throw the code again 30secs to 1 min later.
Currently have the DX FPR which is roughly 3psi lower than the SI FPR and can cause me to run lean.
No exhaust leak because exhaust I’m using is an Apexi WS2 and its super quiet and I have no exhaust leak noise.
Checked the PN for fuel pumps and the SI and the DX use the same fuel pump.
ECU going to be swapped to check if I have a short in my ECU (I have a spare ECU).
This all leads me to believe 3psi of fuel pressure is causing me to throw a lean code which is the reason I have low voltage on the front O2.
Going to try to get a B-series FPR and swap ecu before reporting back.

 

o2 wire had a short as it was giving voltage and grounding out at the same time.

Fixed...but this morning 2 new codes.

P0170 & P0172

Only mods are comptech intake (carb legal), and Apexi WS2 exhaust.

Could it be that the O2 sensor that was swapped in (OBX) is reading incorrectly?

 

Did you solder and shrink wrap the O2 sensor wires?

It's running rich. Measure the fuel pressure and test the FPR while you are doing it. Also check for a leaking fuel injector. If those are fine, the primary O2 sensor may be bad.

 

yes solder and shrink wrapped. Can it be a bad o2 since its an obx...its what the shop had.

I'll messure the fuel pressure when I get/find a gauge. These 2codes only came on while I drove the car when its cold and doesnt come on when it warm. If thats any help.

 

Primary O2 sensor signals are ignored by the ECU until the engine is fully warmed up.

 

it came on again. it's random. I'm going to order up that fuel pressure gauge, and then also check my return line this weekend. Not sure what's the cause of my code.

also got a primary o2 from work i'll be swapping out too.

 

swapped out the FPR (had an extra one) and also changed the air filter to a cleaner one. Seems that code hasn't come back yet. It did come back on when I filled up with gas. I have a new O2 sensor i'll be swapping on shortly.

 

I have changed the FPR checked Fuel pressure, changed o2 sensor and check spark plugs.
Still having P0170 and P0172 popping up every once in a while.
Fuel pressure is 41 with vacuum and 51 without. Spark plugs being DENSO Iridium power’s still look good and looks like they are burning normal (no extra carbon on the plugs). The o2 sensor (OBX) was swapped for a DENSO sensor and the OBX had some black carbon around the base showing that it was running a tad rich.
Process of elimination I will be checking the ECU (I have a spare) that I will swap out to see if it a potential short in the board from the short in the o2 wire originally. Check the throttle body’s ICV and replace with another set of injectors. Anything else I’m missing?

 

i'm back...

changed to another ecu...and I'm still getting the codes.

I looked up in the repair guide and it says my fuel pressure for a b16a is suppose to be high of 37 and 47 for the fuel pressure and I'm getting 42 and 52. So I'm assuming i'm having too much fuel hence the code P0170/P0172?

Is the return lines too small on a D series? or should I try another fuel pressure regulator?

 

Do you have an aftermarket fuel pump installed? If not, check for a clogged fuel return line.

 

Please let me know what you find out I have the same exact codes and the same exact swap just mine is an ex

 

i swapped out the regulator again and used a correct regulator. Before was the d series regulator. The way the mount or something caused the high fuel pressure so my fuel pressure has dropped to the correct pressure.

No fuel pump upgrade.

Still get the code. I'm going to have to check the injectors for leaks now, and also check the evap system if it's holding pressure.

codes that pop are still p0170 & p0172.

 

which code? if you are referring to the original p0131 it's the o2 wiring.

 

I have all three codes you have also the 450 and 453

 

sounds like you need a new engine harness. the original code was fixed when it was rewired for the o2 sensor. Short in the wiring.

now i'm just running rich due to a bad sensor or something. I just want to figure which sensor is bad. Might be my evap purge valve or leaking injectors as those are my last 2 solutions.

 

update.

fuel injectors cleaned at RC Eng.
cleaned throttle body with throttle body cleaner
changed map -> changed back same issue
got new plug wires
going to install new cap and rotor from dealer tomorrow.

still getting code p0170 and p0172 and also get random stuttering around 3k when crusing on the freeway.

 

These fuel pressures were clearly too high.

The numbers should be 30-37 PSI and 40-47 PSI.

Post your current fuel pressure numbers.

 

forgot to mention I did switch out the FPR to the correct one, and the fuel pressure dropped back to 36-46.

 

Stuttering suggests cylinder misfires, so consider the plugs, wires, cap, rotor, ignition timing, valve clearance, and cylinder compressions.