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-   -   No 02 Sensor (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/no-02-sensor-699158/)

doduong11 10-23-07 04:11 PM

No 02 Sensor
 
Hey i was just wondering if the 02 sensor can cause the car to do this.

Well i just finished putting a new engine in and other stuff, at first i was having a hard time starting it up but then later found out that i had a couple of sensors hơok up backward. But anyways i finally got it to start but it kêeps on putting to much fuel into the engine. The reason why i know this is because if i don't rev it up to high RPM to burn all the gas off, eventuălly it will just flơod out the engine and die.

So my question is that, can this happen becuase i don't have an 02sensor plug in?
i have a temporary downpipe but it does not have an 02sensor hơok up. So can this cause the car to do this?

sm0keyii 10-23-07 04:58 PM

Yes

doduong11 10-24-07 02:15 PM

Thanks, and by the way where is the wire for the O2 sensor located at anyways? is it under the intake manifold somewhere? i found and plug under the intake manifold that fits the O2 sensor plug so is this correct?

turboIIrotary 10-24-07 02:36 PM

i was driving my car without a o2 sensor for months and the only affect was bad gas mileage

oilrag22 10-24-07 02:54 PM

No way the lack of O2 sensor can make that happen...
First of all, the O2 sensor is only monitored when the engine is not idling and not WOT. And it only uses the signal when the engine and sensor are up to temperature.
Second if the O2 sensor is not connected the engine management does not use the non-existing signal, but uses a pre-programmed "spare" parameter, which is slighty richens your mixture. But only SLIGHTLY richens the mixture. To prevent damage to the catalytic converter.
So as turboIIrotary mentioned, only thing you will notice when having no O2 signal is a slight decrease in gas milage...

Wargasm 10-24-07 03:04 PM

No O2 sensor will just make the car run a little rich I think.

My car hasn't even HAD an O2 sensor in years (PFC standalone - I run off the programmed maps all the time).

You mention that you had sensors hooke up backwards. This is not possible with the factory harness I don't think... are you installing an aftermarket ECU?

B

doduong11 10-24-07 05:26 PM

Sorry but it is possible to have these two mixed up if you don't know where they go or the differents. The fuel sensors in the fuel rail and the water temp sensor behind the filler neck. These two uses the same plug but only different in colors, one is green and the other is brown. Now the reason why i had them backward is that apparently the previous onwer broke the fuel sensor plug and uses another water temp sensor plug to put in place and therefor i had the two backward, so it is possible.

So you guys are saying that it is not possible for my car to be having too much fuel pumping in to the point where the car will eventually die if i don't rev it up because i don't have an O2 sonsor hook up. So what can this problem be then? and yeah heres what i have upgraded

Large StreetPort
Front Mount
Single Turbo
PFC
550cc and 1300cc
Walboro Fuel Pump
Fuel Pressure Reg
HKS boost controller not hook up

crazyrx7 10-24-07 05:43 PM

What is your base pressure on your fuel pressure regulator? Set it to 38-40psi (take the vacuum line off when your car is idling and adjust it then and then reattach the vacuum line). I bet that is your problem. Also the Walbro fuel pump is notorious for flowing a lot of fuel at idle so you might have to adjust your idle fuel on your power fc. BTW just turn the o2 feedback off on the power fc and run the maps. I don't run a o2 sensor but I do have a wideband o2 sensor that I monitor. You should consider picking one up.

R.K.

doduong11 10-25-07 01:37 PM

ok ill try, but i have never try to mess with this PFC before and i was just wondering how do i turn down the idle fuel pressure on it?

crazyrx7 10-25-07 02:35 PM


Originally Posted by doduong11 (Post 7455533)
ok ill try, but i have never try to mess with this PFC before and i was just wondering how do i turn down the idle fuel pressure on it?

You don't know how to adjust the fuel pressure on your fuel pressure regulator? Which one/brand do you have? BTW the power fc doesn't adjust the fuel pressure; thats what the fuel pressure regulator does.

R.K.

doduong11 10-29-07 03:21 PM


Originally Posted by crazyrx7 (Post 7452999)
What is your base pressure on your fuel pressure regulator? Set it to 38-40psi (take the vacuum line off when your car is idling and adjust it then and then reattach the vacuum line). I bet that is your problem. Also the Walbro fuel pump is notorious for flowing a lot of fuel at idle so you might have to adjust your idle fuel on your power fc. BTW just turn the o2 feedback off on the power fc and run the maps. I don't run a o2 sensor but I do have a wideband o2 sensor that I monitor. You should consider picking one up.

R.K.

No you said to "Adjust your idle fuel on your power fc" that i don't know how to but fuel pressure yes i do know how to and will try that thanks bud.

SLOASFK 10-29-07 03:47 PM

I hope I'm not putting words in anyone's mouth, but I think he meant to adjust how much fuel you're injecting at idle, not to adjust your FPR through the PFC at idle.

With your fuel setup, untuned, it's not surprising that you're dumping way too much fuel. Did you change the injector settings on the PFC to reflect the 1300cc secondaries or does it still think they are 850s?

doduong11 10-31-07 07:30 PM

ok, how do you adjust fuel pressure at idle besides the FPR? and i did adjust the injectors size on the PFC, it was on 720cc and 1600cc so i changed it back to 550cc and 1300cc but other then that nothing else.

crazyrx7 10-31-07 08:52 PM


Originally Posted by doduong11 (Post 7470987)
ok, how do you adjust fuel pressure at idle besides the FPR? and i did adjust the injectors size on the PFC, it was on 720cc and 1600cc so i changed it back to 550cc and 1300cc but other then that nothing else.

The only way to adjust the fuel pressure is by adjusting the fpr if you have an adjustable kind.

R.K.


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