No, it's not a dance. It's a crazy issue I'm having...


I'm datalogging, so I'm watching all the stats... Start the engine, watch for everything. The thing runs smooth as can be when it's in open loop. Instant throttle response. Smooth as can be.

Then, I take it down the road. It starts to warm up and the o2's become "ready." Closed loop begins. Almost immediately it starts to run "differently." The throttle response is no longer crisp and instant. And it no longer runs "smoothly."

Here's the deal, it will spit and sputter at random intervals, and it will nearly stall out every once in a while. Sometimes I can't even keep it running by milking the throttle and it will cut off completely.


I can't explain it much better. It just runs crappily.


I'd like to share my datamaster log files with someone who can read them and maybe figure out what the crap is going on.

Shoot me an email or PM if you're interested. They are .uni files.

 

How do you O2 sensors signals look when it enters closed loop; sounds like bad O2 sensors or faulty O2 sensor wiring.

 

Never known a problem in closed loop but ok in open loop to be anything but either an O2 or O2 wiring issue.

 

Okay, I'll search, but do you have any pointers on testing the o2's?

Secondly, let's hypothetically say that the o2's are the issue. There MUST be a reason that they went bad, right? I can go ahead and tell you that they are not that old 2-3k MAYBE, if not less. So if they are bad, they went bad in a short amount of time.

But why? Injectors? MAF? What could cause my motor to run so poorly it would kill the o2's?

 

Review your logs for the O2 sensors, good O2 sensors should bounce back and forth between approximately 800mV and 100mV. O2 sensors will fail due to overly rich conditions, exposure to leaded gas, can be coated by newly installed coated headers.

 

Thanks, they seem to be doing exactly as you've described.

Here is a link to the datalogs if anyone is interested.

http://www.ordnerprojects.com/files/...ark-houstontx/

 

PS - in the datalog "june3_2" I unplugged the MAF during this run, so that's why you'll see it go away.

 

What are the fuel trims doing?

 

Most of the time it sits on 18 but jumps around to lower numbers, 16, 13, 7, etc...

 

I just uploaded a CSV file for those of you without datamaster.

Here's the link again.

http://www.ordnerprojects.com/files/...ark-houstontx/