GM OBD Readiness monitors - Damn you GM

Lowend

Administrator. .a car, a man, a maraca.
Staff member
Lifetime Gold Member
Mar 25, 1999
16,997
San Jose, CA, USA
Certainly the OBD systems of this era known for being... odd. They EVAP readiness is so random that even the state of CA dismissed it from the test.
With the O2 sensor, my (cheap) scanner didn't have the data abilities to see it was misbehaving. Used a better scanner saw some odd stuff (go figure a $800 scanner is better than a $100 scanner) . Still - odd it didn't throw a code. Interestingly it did throw a slow to respond sensor code after I installed the new ones. Followed some tech advice, cleaned my MAF and that went away.
Got my smog cert earlier today. Such a load off my mind.
 

TIP-T0P

Veteran Member
Nov 4, 2022
312
Contra Costa County
I'm going though this exact same nightmare with my beautiful '97 Z/28 I don't drive anylonger. Just before putting it up for sale a water pump leak, my son pulled it and since he had it all apart he changed the optispark. What a HUGE mistake!!! New optispark was bad as car would die as soon as it warmed up. Wait until it cooled then it would started back up. Replaced opti again, no easy task! No check engine light. Car runs perfectly. Pretty low mile car at 94k. Can't get an 02 "X" to clear out. No check engine light on. Car drives beautiful. Smog station won't even test it without that one "X" cleared. Possible one of the 4 oxygen sensor is bad, of course not knowing which one? Driven it for a few hundred miles, nothing yet.
 

Mike N

Administrator
Staff member
Lifetime Gold Member
Jan 13, 2002
3,125
Spencerport, NY.
I'm going though this exact same nightmare with my beautiful '97 Z/28 I don't drive anylonger. Just before putting it up for sale a water pump leak, my son pulled it and since he had it all apart he changed the optispark. What a HUGE mistake!!! New optispark was bad as car would die as soon as it warmed up. Wait until it cooled then it would started back up. Replaced opti again, no easy task! No check engine light. Car runs perfectly. Pretty low mile car at 94k. Can't get an 02 "X" to clear out. No check engine light on. Car drives beautiful. Smog station won't even test it without that one "X" cleared. Possible one of the 4 oxygen sensor is bad, of course not knowing which one? Driven it for a few hundred miles, nothing yet.

Any pending codes?
 

TIP-T0P

Veteran Member
Nov 4, 2022
312
Contra Costa County
No tests required in Ontario Canada.
Wow, words never to be seen or read here in California, here they go even further to insult you with an offer to give me $1,000 to buy my classic car from me to crush it and get my evil gas consuming, loud exhaust, rubber burning monster off the roads and away from all the new electric vehicles that take over and drive for you because new drivers are to stupid to brake, and keep straight in a lane.
 
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