From | Message |
Stu Dodge Dakota JOIN HERE
12/02/2005 09:30:30
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Subject: Sensors IP: Logged
Message: Which sensors can go bad without throwing a code?
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Dan M Dodge Dakota JOIN HERE
12/02/2005 13:04:48
| RE: Sensors IP: Logged
Message: This is a tough question to answer. Can you give information about the vehicles? Also, are you just asking to be asking or are you having problems?
Really all of them can. They can be "bad" by not being outside of the specs but can cause issues. Sensors work by sendind varying output voltage depending on the sensor and the condition of the component it's monitoring/driving/testing. that voltage could be enough to cause issues but not be out of spec enough to cause a code.
All OBDII enabled vehicles should store codes. Older non OBDII vehicles will not store all codes.
Having said the above, older vehicles could have a code thrown and removed because the issue was resolved or also you may not be able to pull the code with the vehicle on and when you turn it off to get the codes via the key on/off sequence the code will be erased.
A good example is oxygen sensor. If it totally fails, it will throw a code. But it could also be dirty enough to cause gas milage drops without throwing a code.
TPS is another one. It can still be supplying output voltage above requirement for code but not enough for optimum performance. Can cause idle issues, acceleration issues.
I just replaced my TPS, MAP, IAC. The IAC was more of a precautionary. But the others were contributing to a drivablity issue but all did not throw a code.
- Dan M
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Stu Dodge Dakota JOIN HERE
12/03/2005 17:27:42
| RE: Sensors IP: Logged
Message: I have a '93 318 with 190,000 miles on it. I bought it several years ago when it had 90,000 miles on it. The only sensor I've replaced so far was the O2 sensor at 145,000 miles. It never threw a code but I replaced it when when I installed an air/fuel guage, headers and dual exhaust. I also replaces my PCM when it wouldnt fire my #5 injector(threw a code for that, but it wasnt my injector). I like to stay on top of the maintenance and I want to replace the sensors that dont throw codes. I tested my TPS and it was in the parameters (.07 volts I believe). My idle is a bit rough every once in a while and I am thinking it might be my distributor or sensors.
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Dan M Dodge Dakota JOIN HERE
12/03/2005 18:16:17
| RE: Sensors IP: Logged
Message: Sensors do have regular check/inspect intervals.
I am assuming the .07V was ignition on/engine off? Did you watch the volts as you slowly opened the throttle plate?
Have you checked the PCV? Does your 93 also have a breather? Have you checked the grommets/hoses for both?
Could also be the IAC. you can clean it. Just becareful as it is easy to damage it. Rough idle could also be bad ignition coil. Have you checked the EGR?
- Dan M
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MStephens Dodge Dakota JOIN HERE
12/05/2005 12:31:52
| RE: Sensors IP: Logged
Message: For my two cents -- NO SENSOR will go bad and NOT THROW a code. Can't happen.
But alot of conditions happen to a motor that will not throw a code -- bad gas being the biggest offender.
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chilber Dodge Dakota JOIN HERE
12/10/2005 12:00:36
| RE: Sensors IP: Logged
Message: See: http://www.allpar.com/fix/codes.html
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