I was driving my car today using freescan because I haven't got any money to buy TTS and noticed that my BLMs when I am idling are way off. The right BLM will drop to about 112 before going into open loop. Then about 10 seconds later when it goes into closed loop it repeats the process of dropping from 128 to about 112 and going into open loop. However while I'm driving around the BLMs will fluctuate like their supposed to around 128. The BLMs while they fluctuate will range usually from 119-135ish, but an occasional big 140 or so. While I'm idling my BLM cell is 16 and while I'm driving it is 6 under a load, and 2 when I really open the throttle. Just curious what could cause my idle to be rich and if my BLMs sound good. Sorry that's the best I could do since I can record until I've got dough for TTS.

 

Take a look at the right inner fender where a bundle of wires runs down from the top to near the starter. If the bundle has not been modified, it is over wrapped with protective foil. Pull away the foil and look at the wires inside. It contains the O2, knock sensor and starter wires. I think you will find a surprise inside.

 

HUH?

Check your IAC count's as that can cause split BLM's at IDLE. Had the same issue and turned out my IAC was bad and was sticking. Replaced it and it helped a lot. Also what cam r u running as heavier cams can naturally cause split BLMs at idle and what TB are u using as some aftermarket TB's can cause this as well. Do a search and you sould find a few posts on this subject.

 

I saw the IAC at about 12 yesterday, but wasn't really looking at that.

 

FYI: You get 20 free scans with Datamaster before you have to register the software.

 

I know about the 20 free uses, I used them a while back when I first got the car and I was trying to find all the errors and correct. As you can see I'm still having some problems.

 

Almost sounds like the right O2 sensor is not getting hot enough at idle to operate correctly. That would cause it to drop out of closed loop.

 

how would it get into closed loop if it wasn't getting hot enought to keep it on? is there a lower activation temp and a higher "keep alive" temp?

 

Could be an issue with the sensor heater or heater circuit. May heat it up enough to get it into closed loop, then stop heating it until it cycles back to open loop.

 

yeah, you could always try to swap sensors side to side and see if the weird reading switch's too. i had a sensor go bad and no codes and it would do the same sorta thing. cept mine would bogv real bad soon as it hit closed loop, then it would go open and drive good again.

to test the heaters, when the eng. is cold turn the key on and watch the readings. will start out around 452'ish, then drop all the way down to double digits. compare the readings side to side. one might drop rather quickly while the other is slow or just doesnt drop. if working properly should drop way down w/n a min. or two down to like 9 i think. key on engine off i mean.

speedy is talkin about making sure the wires arent melted inside the factory heat wrap. very common. check both sides very carefully. that'll throw everything out of whack.

 

well, the passenger side is a pain in the butt to get the o2 sensor off. going to be a lot of work.