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Discussion Starter · #1 ·
I had the battery disconnected while replacing the fuel pressure sensor. I drove the truck and engine light codes turned off. Repair was successful. Now truck is due for emissions. EVAP is not coming back complete/ready. Everything else is ready. I made a few different trips today probably 50 miles or so. How long does this usually take? The info I'm gathering leads me to believe whoever designed this thing has their head up their ass.
 

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GM's EVAP systems are major PITA. That's about it.

Where are you located? Is the local requirement to have all ready? At least in Texas you can have one not ready in 2001+ vehicles and you'll still pass. Older ones can have two.

Anyway... You just need to keep on driving. 50 miles isn't necessarily enough to complete the necessary drive cycle. It should set eventually. Providing the problem has been remedied.
 

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The evap system literally never passes. It is the single most difficult system to get to a ready status. It isn't a mile marker you need to hit either. It is a combination of MPH, distance and time I believe. I found a GM Tech explanation of how to get it to work and it was awful.
 

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Try keeping the fuel tank less than 1/2 full. That helps.

I went over 2 months before I let our 99 Silverado go below 1/2 tank, and when I did, the EVAP system monitor finally turned green (emission system ready) a couple of days later, and I was able to finally pass the emissions test in Maryland.
 

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The EVAP monitor will only run if the fuel level is between about 1/4 and 3/4. It will not run on a full tank, or a near empty tank.
 

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^^^ This. I'm not sure if Bowtieguru was the same member who mentioned this to me in my own thread about Evap woes, but I gave up replacing parts and driving for no reason to get it to register correctly...lol The downfall is not knowing if my CEL is on for something else, but my truck is pretty beat and I'm just happy it starts up most days...lol

Anyway, I have my MA inspection coming up in a few weeks, and I will be resetting/clearing the code, then keeping the tank full above 3/4, so stopping to get a bit of gas every other day for a week, until I get enough miles, as I only drive 6 miles to work and then I'll stop off to get my sticker and then forget about it for another year...lol
 

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Discussion Starter · #7 ·
tsuintx said:
GM's EVAP systems are major PITA. That's about it.

Where are you located? Is the local requirement to have all ready? At least in Texas you can have one not ready in 2001+ vehicles and you'll still pass. Older ones can have two.

Anyway... You just need to keep on driving. 50 miles isn't necessarily enough to complete the necessary drive cycle. It should set eventually. Providing the problem has been remedied.
Thanks for that info. I'm in CT. I talked to one shop and he said it wont pass with the evap not ready but I'm not sure if he understood I wasnt talking about a check engine evap code.

Yep, did a cold start and drive this morning. Still not ready. Its a PITA alright.

shakenfake said:
The evap system literally never passes. It is the single most difficult system to get to a ready status. It isn't a mile marker you need to hit either. It is a combination of MPH, distance and time I believe. I found a GM Tech explanation of how to get it to work and it was awful.
Yeah I know what you mean. I looked up completing a drive cycle for GM. Its totally insane. I will rename Simon says to GM says. :mrgreen:

chem_man said:
Try keeping the fuel tank less than 1/2 full. That helps.

I went over 2 months before I let our 99 Silverado go below 1/2 tank, and when I did, the EVAP system monitor finally turned green (emission system ready) a couple of days later, and I was able to finally pass the emissions test in Maryland.
Damn, 2 months i'll be past due for the test. F those global freezing, global warming, I mean climate change Nazis :evil:

bowtieguru said:
The EVAP monitor will only run if the fuel level is between about 1/4 and 3/4. It will not run on a full tank, or a near empty tank.
Yip GM says do this, GM says do that, DO THIS! Nope, start over :roll:

ricka182 said:
^^^ This. I'm not sure if Bowtieguru was the same member who mentioned this to me in my own thread about Evap woes, but I gave up replacing parts and driving for no reason to get it to register correctly...lol The downfall is not knowing if my CEL is on for something else, but my truck is pretty beat and I'm just happy it starts up most days...lol

Anyway, I have my MA inspection coming up in a few weeks, and I will be resetting/clearing the code, then keeping the tank full above 3/4, so stopping to get a bit of gas every other day for a week, until I get enough miles, as I only drive 6 miles to work and then I'll stop off to get my sticker and then forget about it for another year...lol
MA? Ouch screw that. I'm in CT and its bad but MA is one place I would not move. Get ready for the Northern states to all get together and screw us over more with tax by the mile and their other plan to raise gas tax. My next step will be to the south. screw these new england tyrants :evil:
 

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These are generically called "drive cycles".
If you have a cheap $20 OBD2 code reader, you can go into I/M Readiness and see the status of each of the drive cycles.
It takes day-over-day trips up to and including highway speed to satisfy all the drive cycles.

I'm also in CT and just had to do this with a project vehicle.
WAY easier with a code reader! No guessing what the status is before you go to the inspection.
 

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Discussion Starter · #9 ·
CT2500HD said:
These are generically called "drive cycles".
If you have a cheap $20 OBD2 code reader, you can go into I/M Readiness and see the status of each of the drive cycles.
It takes day-over-day trips up to and including highway speed to satisfy all the drive cycles.

I'm also in CT and just had to do this with a project vehicle.
WAY easier with a code reader! No guessing what the status is before you go to the inspection.
Youre from CT too? Oh man I feel bad for you, do you feel bad for me too? I'm out of this libtard hell hole ASAP.

Yeah I could see the I/M status on my reader but the problem was the friggin EVAP wouldnt come back ready.

Anyway, I looked up some info and took it to the shop to inform them the info I learned and it went like this...

Maximum Number of Not Ready Monitors / Incomplete Monitors Allowed
Gasoline Powered Vehicles:

- 1996-1999 model year vehicles will be allowed one incomplete readiness/emission monitor; any (1) one "not ready" monitor is allowed.

- 2000 and newer model year vehicles will need all emission monitors in READY or COMPLETE status, with the exception of the EVAP monitor. An incomplete evaporative monitor will not cause a smog check failure. It is the only monitor allowed to be incomplete on a 2000 and newer gasoline powered vehicle.


My truck is 2013 so it is allowed to have evap not ready. So it passed ;)
 

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There ya go! Congrats!
 

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Yeah, zero not-ready allowed here in jail, er, Mass..lol If they see the CEL lit, some places won't even bother starting the inspections...and they are all under camera watch from big brother in the shop, and they randomly drop in to watch whomever they want to ensure nothing is being skipped or wrong...even have to take a picture front and back of device with special camera..

Aside from the insane commie level crap that is, it's a gross waste of money as well...
 
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