o2 sensor, grrrr...

[02gzm]

Ok my car used to have this little problem where shortly after starting (up to 5min) if i let the car rev down the rev range coming up to the lights or something, slow engine braking, the engine light would come on sometimes and give a code 1, the o2 sensor.
It never gave any negative effects. It just came on and i'd turn the key off and on and keep driving and it wouldnt come on again. I just had a few other probs with my distributor dying and had the o2 sensor changed as we found out it was a holden o2 sensor (wtf...). So now after a full service 2 weeks ago and having a new distributor, ignition leads, plugs and o2 sensor everything should be sweet right.
I had been engine braking up to lights slowly after starting the car for the last few days after getting my car back with no problems, then today as i was slowing down just as i started putting the clutch in the engine light came on and it was a code 1 again.
Now i think my injectors may be dirty as the car splutters a bit at startup, which clears up after a few seconds and the idle smooths out and the car runs fine. I originally thought that problem was caused by the faulty distributor but the only other thing i can think of is a fuel delivery problem. The car is a b16a with a chipped p30 ecu. I got some injector cleaner which i'm gonna put in tomorrow and i'll reset the ecu as well afterwards. I'll get the injectors and fuel pump checked next week when i get a bit more dosh but has anyone got any input about the o2 sensor and if they think it could be caused by a fuel delivery problem with it only happening at low rpm and just after startup?

[blk_shadow]

it can be the relay too. fuel pump relay?

[omgzilla]

No holes in the exhaust or or blockage in the catalytic converter?

What OBD spec is you B16A? B16A1 or 2?

If B16A2: Was it the primary or secondary 02 sensor that you replaced?

[aaronng]

Chipped p30 ecu? What map is it running? Tuned to your car or a generic one? If it is like most "performance" generic maps, you might be running very rich, thus fouling the O2 sensor and also causing carbon buildup in the combustion chamber.

[Limbo]

b16a2 only has 1 O2 Sensor a 4 wire one.
I brought a new replacement for about $100 at Mekong spares


No holes in the exhaust or or blockage in the catalytic converter?

What OBD spec is you B16A? B16A1 or 2?

If B16A2: Was it the primary or secondary 02 sensor that you replaced?

[02gzm]

Its a JDM b16a, OBD1. And it was the 4wire primary o2 sensor. I'm not sure on the tune as the ecu came with the car when i bought it over a year ago. I'm sure they said they checked the A/F when they put everything in though. I had a look at the chip and it has a mugen sticker on it but it could be bloody anything. I think the next thing i'll save up for is a hondata ecu and get it tuned properly. It's just odd cos i can pretty much make the engine light come on on command but only a few min after startup.

[aaronng]

Mugen sticker on it = generic flash for mugen equipped b16a. They also run pretty rich. I'm guessing either your spark plugs are fouled (easy to check by pullint them out) or the O2 sensor is fouled. Do you have a non-chipped b16a ECU to swap in?

[02gzm]

The plugs were changed and checked when the work was done. I might be able to get my hands on another ecu. I'll try that out.