I'm using freescan to see if I can figure out why my car is running so rough. I noticed that the oxigen sensor volts keep moving from 0.1xx up to 0.9xx. Is this normal, what else should I look for?

EDIT: It only does this while in closed loop, in open loop the volts are fairly steady at 0.08x

also, what should my BLMs be at idle?

TIA

 

The O2 sensors values don't matter until the car goes into closed loop. They tend to move very little until the car warms up and goes into closed loop. They should at this point go rapidly between 0XX-8XX unless you go wot and then they will be in the 800's and 900's. You want your long term BLM's to be as close to 128 as possible but 125 to 131 should be close enough. If they are higher than 128 you running lean and below your running rich. I used Freescan for a while then changed to Datamaster which is much easier to use and you can easiely email others your scan to view. Its free for the first 20 logs and that should be more than most will need.

 

the BLMs are at 108, could that be causing my car to run rough, I also forgot to mention that It started doing this right after I did Seafoam.

 

Blm's can't go below 108 and when they do the pcm will set a rich code. It appears the car is adding way more fuel then the engine needs. Need to figure out whats wrong. You need someone to look at you logs.

 

in open loop, the oxygen sesnor shouldnt be above about .2 volts (.1-.2volts). In closed loop, it should fluctuate between .1-.9 volts.

 

the car feels like it misfires and right when it does it the o2 volts go to 1.0xx. I took one spark plug out and it was fouled,but I figured it was because its running so rich. if it was misfiring it should throw DTCs right? I have to drive this car to work every day and I'm afraid i'm going to fu#k something up If I keep driving it like this.

 

If it running real rich you can mess up the engine if you do it for any lenght of time. I would figure it out before i drove it anymore unless you drive it to a mechanic.

 

Read the A/F management section of this:

http://members.aol.com/InjuneerZZ/ScanMast.htm
Yes... the engine appears to be running pig rich, the PCM is pulling out all the fuel it can using the BLM's, and its still running rich. It will run rough under those conditions. What do the short term fuel corrections look like? Are they swinging back and forth an equal amount on bost sides of 128, or are they also well below 128 most of the time.

How did you use the Seafoam? The problem would appear to be related to that.
With an AIR system, at cold start, both O2 sensors should read about 450mV. With the AIR pump running, as the O2 sensors start to heat up, the voltage will drop steadilly, into the 00x range. At that time, the PCM sees they are operating, and it switches to closed loop (if the coolant is warm enough, and after about 205 seconds from cold start).

 

I just logged it and this is what I see on the log, it seems a little wierd:
BLM CELL---10
BLM LEFT--137
BLM RIGHT--147
INTEGRATOR L--109
INTEGRATOR R--106

EDIT:I was reading that link that you posted and I think the O2s are fine and all that stuff above seem to be fine also

Sorry, I couldnt figure out how to post the log

oh and I used seafoam through the brake booster line.

 

Your last post showed a freeze frame. We would need to see more than that to determine what the car is doing. The long term ones are the important ones. My short term are all over the place so don't pay much attention to the short. If your getting 147 and 137 then that would be when the car is running lean. If you put the Freesan from excel into an email it can be sent to one of us to view.

 

OK, I sent it to injuneer,I couldn't get access to your E-mail

EDIT: also, I just scanned it again and the integrators stay in the 12X,the BLMs stay at 128, and as soon as it enters closed loop the BLMs start to drop and the integrators stay about the same.

 

just wanted to let you guys know that my car is running strong again, I replaced both O2 sensors, took it for a test drive and it was still the same, so I replaced the sparkplugs, took it for a test drive and it got allot better after a while of driving and now its back to normal.

Thanks

 

It takes a little time to adjust. I replaced the plugs and went from 16's to 13's on my 1/4 mile runs. If you were running rich because of bad O2's the plugs will be fouled.