How do you know if your O2 sensors are going bad? (Hows the car feel when you accelerate?) I keep hearing about them on here, and mine have never been replaced.
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94 Formula LT1 (Aqua Metallic) - Auto. - 104,000 miles - Charcoal Leather Mods: Magnaflow Muffler, Lingenfelter CAI, MadZ28 Tune, 160F Hyp. T-Stat., 1LE Elbow, & Summit Cutout. Options: 155 MPH Gauge Cluster, & 255-50ZR-16 Tires. -
Your car doesn't use them at wide open throttle. But at part throttle & idle after the car is warmed up, the car needs them to keep the mixture correct. You need a scanning device to make sure they are switching. Older sensors start switching more slowly and it affects mileage. Usually, they last 60k miles or so before out of spec. There might be a way to troubleshoot them with a multimeter, but it's cumbersome and a rapidly changing value is impossible to watch on a digital meter. Maybe an analog meter would work, but a scanner is much better than that. There is a spec for how many times a sensor is supposed to switch in a given time, but I don't have it handy. -
yesterday i used a GM Tech2 scaner and it said that my left bank O2 sensor failed the test, but it's the only thing it could find wrong...my car had been running like crap for a month now...but you just said that an O2 sensor doesn't effect WOT operation...mine is very effected....
tired of trying to chase down this issue...1998 TA M6 SLP Lid, Cold Air and Bellow, Flowmaster 3", Centerforce DF, Fast Toys MAF ends, JET skip shift eliminator 312rwhp/366rwtq
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Your car runs open loop at WOT and relies on the BLMs and the Fuel Enrichment tables to determine the total fuel. Maybe if the BLMs are all screwed up from a bad O2 sensor, it could affect WOT, but I am unsure of that. Did you look at your BLMs? If they are around 128 or so when you go WOT, or they switch to 128 at WOT, then the mixture should be OK, assuming you don't have bad injectors or something.Originally posted by FireFinder20yesterday i used a GM Tech2 scaner and it said that my left bank O2 sensor failed the test, but it's the only thing it could find wrong...my car had been running like crap for a month now...but you just said that an O2 sensor doesn't effect WOT operation...mine is very effected....
tired of trying to chase down this issue...
If your problem isn't fuel, maybe you have a bad opti, plug wires, or plugs to go along with a bad O2 sensor. You may have more than one problem.Comment
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switched the opti (gonna do it again tomorrow), plugs and wires....
BLMs? I'll look for it today when i take a snapshot on the Tech2 128 is the number in open loop...
but what about closed loop? that's when it's running bad, it's fine in open loop....1998 TA M6 SLP Lid, Cold Air and Bellow, Flowmaster 3", Centerforce DF, Fast Toys MAF ends, JET skip shift eliminator 312rwhp/366rwtq
92 Lincoln Mark VII LSC For Sale
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This here applies to closed loop. If one side (or both) BLMs are a little higher or lower from 128, say 121-135, then you have a slight lean or rich condition, but not too far out of line. The PCM can adjust for a small air leak or slightly rich condition, but if there is too big a problem, it may run out of adjustment. If the BLM is pegged at the min 109 (adding fuel) or max 160 (pulling fuel) then it is out of adjustment room and the car will run badly to the point that it is noticeable. The O2 sensors should be switching rapidly from some low value of millivolts to some higher value say 750 mv or so. If it is stuck at any one number after the car is warmed up and in closed loop, then it is not working. The only exception is if you log a WOT run, the readings will usually be 900+ or so, and your BLMs MAY go to 128 if the PCM was pulling fuel when you hit WOT, otherwise it may be some other number greater than 128.Comment
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Speaking of bad 02 sensors....
1) My car was scanned with the Tech2 too. The passenger side 02 sensors (pre and post cat) plus the injectors pulse width readings were low in relation to the driver's side: Those mean I have to replace the 02 sensors plus the injectors???
The mechanic performed a injector cleaning procedure with a pair of pressurized cans, replaced the fuel filter and cleaned the EGR valve. He told me, since the Iridium spark plugs were installed in july 02, i must replace them too. He couldn't scanned the PCM again because the shop closed time, but I noticed a better engine performance, much better......
2) Symptoms: poor gas mileage ratio, low performance, more carbon builtup in my exhaust tips. No stalls stumbles or some kind of epileptogen movements.
3) No DTCs, even in the "history bank".
4) my car has 58k miles: Opti, spark plug cables, injectors stock. MAF stock cleaned already.
Soooooo, I really appreciate your comments about this mess.
Thanks a lot in advance
Dochidalgo97 A4 Pontiac Firebird Trans am with $everal mod$Comment
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Doc, you can always switch parts to the other side - pre-cat O2 sensors, then injectors to see if the problem follows the particular part. Ain't never heard of no epileptogen movements, though, so can't help ya there..Originally posted by dochidalgoComment
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When they are dead, they will usually test at a steady 450mV.Originally posted by EquatorHeat00Comment
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Well Kevin, those 02 sensors never reach the 450 mV readings....but nobody told me about replace them.......now I'm pi.....off!!!
Are the Bosch ones fine brand?
Thanks
Dochidalgo97 A4 Pontiac Firebird Trans am with $everal mod$Comment
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Denso and Bosch are good replacements. Are you getting any o2 sensor specific codes?Originally posted by dochidalgoComment
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No, no DTCs...it seems they are expecting to get one to make the right diagnostic in spite of the symtoms and readings....
I doubt the spark plugs are bad, but I'm not expert in this matter.
But how to solve the low injector pulse widths in the passenger side?
Regards
Dochidalgo97 A4 Pontiac Firebird Trans am with $everal mod$Comment
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