Front Oxygen Sensor

[merqury]

For a while I have been having this problem. My check engine light came on and I scanned with DSMlink and it says front O2 malfunction. I replaced the O2 and it still is giving that code. Another thing to note is that my car only gives me 130 miles per tank and whenever I go WOT, I can see black smoke come out of my exhaust. Now the smoke is not thick but it is noticable. I do have a wideband and after the car is warmed it reads anywhere from 13.0-15.0 A/F ratio at idle and while driving about 11.0-12.0. This might be a dumb question but is this mostly a tunning issue. How come the engine keeps coming on even though I replaced the front O2? One more thing to help diagnose the problem is that in second gear at about 5000RPM the exhaust pops thick black smoke. Hope that helps guys!

 

[JohnCIV_Talon]

It could be a tuning issue, but also a really bad boost leak. That would be another cause of the horrible gas mileage. Have you checked for boost leaks?

 

[diablos991]

I second the idea for a boost leak test.

It could possibly be a tuning issue as well. You could post up a log here and we can help look at that. Regardless, a boost leak test should be done.

 

[merqury]

I did a boost leak test just yesterday and there was one and I fixed it. Other then that, nothing else. I will go home and put up some logs but in the meanwhile any other suggestions? How about the check engine keeping coming on even though I changed the front O2?

 

[JohnCIV_Talon]

Could be a bad wire?

 

[diablos991]

Are you getting the o2 sensor code? or the P0170 fuel trim code?

 

[merqury]

I'm getting the O2 sensor code.

 

[JohnCIV_Talon]

well whats the code number?

 

[merqury]

I'll have to scan it again when I get home. I will let you guys know. Any other suggestions as to what could be going wrong with the problems stated above?

 

[JohnCIV_Talon]

Do you have any kind of logger to see what your o2 sensor is reading? Running really rich like you are can put out an o2 sensor out, so that might be why it came back on. You may have burnt out another one.

Also, have you done anything with your rear o2 sensor? Maybe you are confusing it with the front one. Just a possibility.

 

[merqury]

Only thing I did John was install a AEM wideband and for that I welded a bung into the DNP away from the turbo. The rear O2 is untouched and I am 100% positive it is the front O2 thats malfunctioning, at least thats what it tells when I scan. As far as the code, I will get that to you guys as soon as possible. Also, I am using a DSMlink to do all my tunning and data logging so, I can also get the reading for the O2 as well for you guys. Anything other possibilities? I am thinking its mostly tunning but what do you guys think? Would tunning effect gas mileage that much, I mean 130 miles a tank, I'll go bankrupt with gas prices rising by the minute!!

 

[viperkd77]

ive been having the same kind of problem. I have no cel, but i put a 3 inch catless exhaust on and my gas mileage was cut i half. I get like 150 miles per tank as well. I run real rich in openloop with black smoke everywhere. ive checked the timing, ive checked for boost leaks. I even replaced the front 02 (dumb of me) and nothing changed. Mine is an a/t gsx and my cruise rpms are much higher maybe causing my car to go into openloop too early. not sure. thanks