HELP!!!!!! Keep getting CEL for front 02 sensor, even after I changed it.

[leexong77]

title says, I changed both front and rear 02 sensors yesterday. Before that I was getting a CEL and ran the code and came up as the front 02 sensor. All was good until today while I was driving home from work and I notice the car was driving weird at low rpm, like it was hesitating then it pick right up again. I knew something wasn't right. I step on the gas, as the rpm reach between 5-6k the CEL came on again. When I got home, ran the code and came up as the front 02 sensor. Have anybody experience something like this before? Is there something else I need to do?....... After I got it home and let it sit about half a hour, got in start it up, drove it and it felt normal. But in the back of my mind I have a feeling the CEL will pop up again. This worries me so please help guys.

 

[Larry Bastanza]

Code #??

 

[pingu81]

What's your setup from the exhaust manifold back? Aftermarket?

 

[leexong77]

Hi Larry, mine is a 1991 na1, obd1. The CEL blinks once a pause and one again. check here and ssid that its front 02 sensor. The cel light came on again today. My car is stock. I'm losing my head here trying to figure out whats wrong.

 

[leexong77]

Still can't figure out whats wrong. Check my coils and sparks plug to make sure, I know they have nothing to do with why my front 02 sensor keep coming on. The coil and spark plug looks good. Check my intake and the filter is still pretty much new, Changed it last summer. I'm out of ideals as to what to do next. When the CEL comes on, if you turn the car off then it goes away and stay off until I park the car for a long period of time. When it's turned off and the CEL goes away, the car drives fine. Before I changed my 02 sensor, the car idle jumps up and down between 700- 1200 rpm. But now that I did change the 02 sensor it idle just fine. I have notice that there is a little bogging at low rpm and it goes away when it speed up pass 2500 rpm. What can all this be? What do I need to do? Will I be btter off taking it to the dealers to have them check it out?

Thanks

 

[Larry Bastanza]

Time to check your fuel pressure...

 

[trident17]

My car has developed a similar problem Both O2 sensors have been changed but the engine is hesitant at low speed. I don't get the CEL anymore so perhaps I should also check the fuel pressure. Is there a thread for fuel pressure anywhere?

 

[A.S. Motorsport]

If you have a fuel pressure test kit (a gauge on with a hose attached) you can remove the 6mm bolt on the fuel filter and screw the tester on.

Before removing the 6mm bolt on the top of the banjo connection first open your fuel filler cap, and place some rags around the fuel filter as it will leak a bit whilst pressure releases.
Be sure to replace the copper sealing rings,

I'd also replace the fuel filter if you haven't already done so.

 

[leexong77]

I haven't try to test my fuel pressure yet, but I'd try the resistor test to see if it is the resistor or my fuel pump. So, I jump the resistor and the car still runs like the same. Does this mean it's the resistor or my pump? And when I do the pressure test for the fuel pump, do I take the banjo out too, then connect the gauge or just the smaller bolt that goes into the banjo? Thanks