Ok, well I'm trying to help some kid out on talk and he is saying that he bought his 420a already boosted, with a plx wideband and the wideband has been used to replace his front o2 sensor, I was under the impression narrowband simulation was for the rear o2, anyways, I want to steer him in the right direction besides just telling him to come here (I already did that) so if anyone has any input on the following details he's given me, would you mind giving me some input.

i am having trouble tring to get the air/fuel right it wants to run rich most of the time mostly when just at crusie. the plx device has a grey wire that your suppose to run to the ecm for the factory o2 sensor and when hooked up it want to run alittle lean and stumble alot if i unhook it and let the check engine lite come on it runs alot better but more to the rich side. im at a stump on it and not sure what to do or check. thanks alot


If I understand you right, your rear o2 sensor has been removed and your wideband is simulating output for the ecu to see as if the rear o2 sensor was still there. I would double check the wiring and pinout diagram to make sure the grey wire is run to where it is supposed to be. Regardless, no signal for a rear o2 sensor should not affect performance of the car, it basically just tells the computer whether or not the catalytic converter is working. Do you know what the CEL is for? You can do the keydance (search it on 2gnt) and get the codes that the computer is throwing. As for running rich when cruising it may just be that if you have 255's your fuel pressure is a bit too high for them. Are you running significantly rich or just a tad on the rich side? For reference, with stock 235 injectors, your idle fuel pressure should be between 47-55 psi and static (0 psi) should be around 60 psi. You may want to lower your idle fuel pressure a little bit to start off depending on where it is at now.


no the wide band is in place of the front 02 sensor. and tonite i went to the store and it was like always and when i came back out and was coming home it would run real lean when tring to boost and then all the sudden lanch and run like usual then let off and try again the samething all over any clue on this im totally confused



p.s. you have yahoo mess. would be easier to talk like that

nope the wideband 02 does take the place of the top 02 sensor with the narrowband input to the ecu . i hear you will have a lot of problems with using the narrowband input on our ecu . just tell him to weld another bung and put back his stock 02

^^^^ is correct, our ECU does not like a simulated output and the stock ECU will make sure it runs rich without the correct O2. he must run both Sensors, stock and Wideband.


Terry

Originally posted by Star Turbo Talon
^^^^ is correct, our ECU does not like a simulated output and the stock ECU will make sure it runs rich without the correct O2. he must run both Sensors, stock and Wideband. Terry

This is what I always thought. Glad I was thinking right haha.

Does the 95 ecu respond any differently to the simulated O2? I know its a different ecu design but I dont know if it responds any differently in this particular instance.

95 reacts the same way...it doesnt like it

It is not just our ecu. If you read about ANY of the o2 simulators on the market you will see that almost all of them, if not ALL of them say that they are for use for the REAR o2 sensor only.

I tried mine out with my zeitronix setup for a week or so on my 95 and I didn't see any problems. I actually kept a damn near exact 14.7 AFR below boost rather steadily. What issues occur that makes the ecu not like the simulator? And I don't even have a rear 02 sensor on my year.

Originally posted by jack_of_trades
I tried mine out with my zeitronix setup for a week or so on my 95 and I didn't see any problems. I actually kept a damn near exact 14.7 AFR under boost rather steadily. What issues occur that makes the ecu not like the simulator? And I don't even have a rear 02 sensor on my year.

well as far as the issues go, idk. But you shouldn't be seeing 14.7 when under boost, you want to tune to about 11.5 under boost

no wideband should ever be ran off the rear o2 reegardless. i believe its supposed to be 16 or 18'' from turbo which is about a in up from the front 02 .

Originally posted by cs82685... you shouldn't be seeing 14.7 when under boost, you want to tune to about 11.5 under boost

Derr,lol. I obviously meant pre-boost. I am tuned to 11.5 AFR boosted.

Yeah as far as I know, the only real purpose of the rear O2 is to monitor the catalytic converters effectiveness.