Failed emissions AND code 23 & 34
02-27-2003, 05:36 PM
#1
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Failed emissions AND code 23 & 34
C0 is a might too high at slow speeds. Check codes today too and I had these two. Since someone has my shop manual can I have those two?
BTW I have bad valve guide seals, could that cause my C0 to be a little too high at low speeds? Thanks in advamce
BTW I have bad valve guide seals, could that cause my C0 to be a little too high at low speeds? Thanks in advamce
02-27-2003, 05:44 PM
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Re: Failed emissions AND code 23 & 34 (thrills)
Yeah the seals can affect some oil burning, but you should fix the codes first.
34 is a MAF code, relays on the firewall or the sensor itself and check for vacuum leaks.
edit-since yours is an 85, the relay is inside the dash somewhere (dont know 85s)
23,The code is for the MAT sensor. It is located under the plenum toward the back, goes up into the bottom of the plenum from underneith.
Sounds like it is disconnected, wire broken, bad connection or very bad sensor.
if you can get to it, the sensor should have resistance of 185 ohms at 210* and 25,000 ohms at 0*. At 70* it should read about 3,400 ohms with an ohm meter.
To set this code, yours is reading more than 50,000 ohms.
Fix the 34 first, it may be tripping the MAT code. These would also affect emissions, so that might be why you failed.
[Modified by vader86, 5:47 PM 2/27/2003]
34 is a MAF code, relays on the firewall or the sensor itself and check for vacuum leaks.
edit-since yours is an 85, the relay is inside the dash somewhere (dont know 85s)
23,The code is for the MAT sensor. It is located under the plenum toward the back, goes up into the bottom of the plenum from underneith.
Sounds like it is disconnected, wire broken, bad connection or very bad sensor.
if you can get to it, the sensor should have resistance of 185 ohms at 210* and 25,000 ohms at 0*. At 70* it should read about 3,400 ohms with an ohm meter.
To set this code, yours is reading more than 50,000 ohms.
Fix the 34 first, it may be tripping the MAT code. These would also affect emissions, so that might be why you failed.
[Modified by vader86, 5:47 PM 2/27/2003]
02-27-2003, 05:52 PM
#4
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Re: Failed emissions AND code 23 & 34 (vader86)
Thanks! Emailing this to my friend who's going to try to help me fix it :seeya
02-28-2003, 03:34 AM
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Re: Failed emissions AND code 23 & 34 (thrills)
Verify that your ECM goes closed loop when warmed up and stays there at mild throttle positions.
Jumper ALDL pins A&B and start the engine. After a while the SES should settle to about a 1Hz flash rate indicating closed loop. The On/Off flashes should be of about equal duration indicating a stoch mixture.
Then step the throttle up to various RPMs, hold position till the SES flashes again settle to equal On/Off durations. If at some point they do not settle to equal durations at about 1Hz, replace the O2 sensor.
Jumper ALDL pins A&B and start the engine. After a while the SES should settle to about a 1Hz flash rate indicating closed loop. The On/Off flashes should be of about equal duration indicating a stoch mixture.
Then step the throttle up to various RPMs, hold position till the SES flashes again settle to equal On/Off durations. If at some point they do not settle to equal durations at about 1Hz, replace the O2 sensor.