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Dying O2 Sensors!

G

GalDemSuga

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Grab your popcorn this one is a riddler:)

New motor with 1700 miles keeps killing O2 sensors. I've replaced 4 so far on average one every 2 weeks. today it got even more serious. I started from Pikeville, KY to Pittsburgh, PA this morning. I filled her up and traveled for 111 miles before I was forced to stop for fuel and to check an enginne code. I was averaging 9.25 mpg's but after filling up and doing the math, it dropped off to 5.4 mpg's. The codes were 13, 43 and 45.

The O2 sensor was 10 days old (code 13 and 45) and the ESC is 4 days old (code 43).

Could a 20 yr old catalytic converter be killing my O2 sensors and causing her to burn twice as much fuel? I need some guidence here.:doah:
 
Two possibilities. One, if its a new motor, it may have been put together with something fatal to O2 sensors.
Many RTV sealants will poison one as they cook out.
Or, maybe the wire is being spliced instead of using the connector. You can splice the wire from the connector to the engine, but you should never spice the wire from the connector to the sensor.
Many of them get their outside oxygen reference through the hookup wire. If its spliced, no reference.
Or, I guess some kind of fuel additive. Too much alcohol will kill one too.

J.
 
So what makes you say you "keep killing 02 sensors"? Just because you get a code for an 02 sensor doesn't mean that is the problem. Many times the problem lies elsewhere.

Have you tested the 02 sensors and found that they are in fact bad?
 
4X4HIGH said:
So what makes you say you "keep killing 02 sensors"? Just because you get a code for an 02 sensor doesn't mean that is the problem. Many times the problem lies elsewhere.

Have you tested the 02 sensors and found that they are in fact bad?
Click to expand...

the exact beginings of the long story of lets throw parts at it.


you got to find the full reason it thew the code. and understand why it thew the code. or you might as well paypal me the money you are tossing away.
 
4X4HIGH said:
So what makes you say you "keep killing 02 sensors"? Just because you get a code for an 02 sensor doesn't mean that is the problem. Many times the problem lies elsewhere.

Have you tested the 02 sensors and found that they are in fact bad?
Click to expand...

No I havent tested any of the sensors. This is what I've observed from logging using WINALDL. The O2 voltage keeps attenuating from 0.0002 to 0.8000 and BLM's from 115 to finally stopping at 172.

Finally, it throws code 13, 43 and 45.
 
sweetk30 said:
the exact beginings of the long story of lets throw parts at it.


you got to find the full reason it thew the code. and understand why it thew the code. or you might as well paypal me the money you are tossing away.
Click to expand...

luckily for me the sensors are all warrantied:)
 
A bad oxygen sensor can not set a code 45!! at least not a single wire sensor. Code 45 means rich, means sensor is reading high voltage, dead sensors don't make voltage! Therefor this sensor is fine as are the other 3 or 4 you wasted your money on. You have effectively been shooting the messenger not the culprit!!

You need to look at what is causing the mixture to go rich. Listed in most likely to least likely.

1: MAP sensor vacuum line leaking or disconnected

2: MAP sensor electrical connector and/or bad sensor (may need to read datastream to check or use a DVOM to check voltage)

3: High fuel pressure caused by
a: plugged return line
b: bad regulator (use a pressure gauge, should be 12-13 psi tops)

4: Grounds, check/replace ground wires at back of head and at t-stat housing

5: Plugged exhaust, unlikely though. If exhaust plugged enough to set code car usually won't be able to hit highway speeds.

6: Oxygen sensor wire could be shorted to voltage causing computer to think rich HIGHLY UNLIKELY.
 
bigblock72 said:
A bad oxygen sensor can not set a code 45!! at least not a single wire sensor. Code 45 means rich, means sensor is reading high voltage, dead sensors don't make voltage! Therefor this sensor is fine as are the other 3 or 4 you wasted your money on. You have effectively been shooting the messenger not the culprit!!

You need to look at what is causing the mixture to go rich. Listed in most likely to least likely.

1: MAP sensor vacuum line leaking or disconnected

2: MAP sensor electrical connector and/or bad sensor (may need to read datastream to check or use a DVOM to check voltage)

3: High fuel pressure caused by
a: plugged return line
b: bad regulator (use a pressure gauge, should be 12-13 psi tops)

4: Grounds, check/replace ground wires at back of head and at t-stat housing

5: Plugged exhaust, unlikely though. If exhaust plugged enough to set code car usually won't be able to hit highway speeds.

6: Oxygen sensor wire could be shorted to voltage causing computer to think rich HIGHLY UNLIKELY.
Click to expand...

I got codes 13, 43 and 45 initially I cleared the codes and drove for 150 miles while logging data. During that time I got code 13 only and continued to burn twice as much fuel as I had been burning before with BLMs @ 172 and the O2 voltage all over the place.

Every sensor on the intake is new (not older than a month) and all vaccum lines were replaced by me.

I will check the items listed and see what gives.
 
If you're only getting 13 after a long drive I'd check grounds. A bad ground can cause a 43 as well.

If the grounds look ok on the motor then connect a DVOM at the ground pins at the computer and check voltage drop.

I'm glad you have a way to check datastream it sure makes things a lot easier.
 
id definitely look into the cat to make sure thats not the problem to. ive had friends almost light the underside of their trucks on fire because they get so hot when they get old.
 
bigblock72 said:
If you're only getting 13 after a long drive I'd check grounds. A bad ground can cause a 43 as well.

If the grounds look ok on the motor then connect a DVOM at the ground pins at the computer and check voltage drop.

I'm glad you have a way to check datastream it sure makes things a lot easier.
Click to expand...

i gotta find the computer first:D then I can check for the voltage drop. I will have an emission test done too to see about that CAT.
 
A properly working 02 sensor should show varying voltage and it should switch back and forth rather quickly.
 
4X4HIGH said:
A properly working 02 sensor should show varying voltage and it should switch back and forth rather quickly.
Click to expand...

OK. Thats seems to be what they were doing before the Code 13 was thrown. I've got a new O2 in there now and I will drive about 180 miles today so I will log and hope for the best.
 
Just because it doesn't switch, again does not mean the sensor is bad.

PROPERLY OPERATING in closed loop, voltage should go above and below about .450 all the time. If it stays above or below, that ONLY indicates that the motor is rich or lean, it STILL does not indicate the O2 sensor is bad.

I got a rich O2 code on my truck...when I broke an intake rocker arm stud, the plenum filled with gas, and fuel started pouring into the other cylinders!
 
dyeager535 said:
Just because it doesn't switch, again does not mean the sensor is bad.

PROPERLY OPERATING in closed loop, voltage should go above and below about .450 all the time. If it stays above or below, that ONLY indicates that the motor is rich or lean, it STILL does not indicate the O2 sensor is bad.

I got a rich O2 code on my truck...when I broke an intake rocker arm stud, the plenum filled with gas, and fuel started pouring into the other cylinders!
Click to expand...

right now i've got a properly functioning O2 but still running rich. I'm getting BLM, DRP and rich flags. I got an emission test done and it indicated that she was running rich, so she failed the test.

BLM's are about 119 to 126 now.
 
Search for eagle mark's post with the TBI troubleshooting flow charts in it. Pretty recent.

I've heard that you are SUPPOSED to cure the highest number code first, but not certain that is true. In this case it makes sense if Code 13 is O2 and you are getting other codes, the cause of those is probably the cause of a rich condition.

BLM's should be 128 if everything is perfect.

Really though, start with the flowcharts and let the designer of the system tell you how to test it, whats wrong, and how to fix it.
 
dyeager535 said:
Search for eagle mark's post with the TBI troubleshooting flow charts in it. Pretty recent.

I've heard that you are SUPPOSED to cure the highest number code first, but not certain that is true. In this case it makes sense if Code 13 is O2 and you are getting other codes, the cause of those is probably the cause of a rich condition.

BLM's should be 128 if everything is perfect.

Really though, start with the flowcharts and let the designer of the system tell you how to test it, whats wrong, and how to fix it.
Click to expand...

no codes now, just wacked BLM's and rich condition
 
I'd be thinking injectors or a fuel leak if everything else is under control, and the sensors seem to be within "good" parameters at idle/cruise.
 
dyeager535 said:
I'd be thinking injectors or a fuel leak if everything else is under control, and the sensors seem to be within "good" parameters at idle/cruise.
Click to expand...

no leaks from injectors. this is whats so puzzling? i can't figure out why she is duming more fuel than needed. no leaks, vaccum or otherwise, and no codes now. BLM's are hanging out around 119 to 124 and I'm getting DRP, BLM and Rich flags.
 
Does this rig have a custom chip in it? If so then maybe someone needs to reburn the chip.
 
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