Passing OBD2 emissions with EVAP code?
01-13-2011 | 04:34 PM
#1
Thread Starter
Joined: Jan 2002
Posts: 1,801
Likes: 28
From: Dutchess, New York
Passing OBD2 emissions with EVAP code? Wanted to run this by you guys here to see if anyone had experience or advice. I didn't know of a better fitting section on Tech.
My DD is an '03 Caddy SLS. Been fighting P0440 codes (EVAP large leak) for a couple years. Luckily enough they've gone away the past 2 years when emissions time came. Not so lucky this time and I'm due before the month's end. Yes, I've troubleshot the problem a lot over the years. Replaced the gas cap twice, vent solenoid, and recently the fuel tank pressure sensor. Traced out almost every inch of line from the tank to the purge solenoid, no leaks. I think the culprit is the seal between the pump assembly and tank as there is a good bit of corrosion (NY car) and a faint gas smell. Really don't feel like dropping the tank and replacing. Or paying a shop a bunch of money.
Anyways, as per documentation the EVAP test only runs when the tank is between 15-85% full. If I clear the codes, and keep the tank near full, I assume the EVAP monitor would come up as "Not Ready", however I also believe 2000+ OBD2 cars are allowed one "Not Ready" monitor and can still pass. Think my plan will work?
My DD is an '03 Caddy SLS. Been fighting P0440 codes (EVAP large leak) for a couple years. Luckily enough they've gone away the past 2 years when emissions time came. Not so lucky this time and I'm due before the month's end. Yes, I've troubleshot the problem a lot over the years. Replaced the gas cap twice, vent solenoid, and recently the fuel tank pressure sensor. Traced out almost every inch of line from the tank to the purge solenoid, no leaks. I think the culprit is the seal between the pump assembly and tank as there is a good bit of corrosion (NY car) and a faint gas smell. Really don't feel like dropping the tank and replacing. Or paying a shop a bunch of money.
Anyways, as per documentation the EVAP test only runs when the tank is between 15-85% full. If I clear the codes, and keep the tank near full, I assume the EVAP monitor would come up as "Not Ready", however I also believe 2000+ OBD2 cars are allowed one "Not Ready" monitor and can still pass. Think my plan will work?
01-13-2011 | 04:54 PM
#2
Just to clarify I believe it's 2001 and newer that allows 1 "not ready."
Anyways, I recently had the same problem with my 2000 Civic. On the day of my inspection I used my Autotap to clear the codes and then drive ~3 miles to work. I left work in the afternoon and drove ~40 miles to the inspection station. Within the first 10 miles of the drive all of my readiness tests were complete except for the evap system. Evap did not complete by the time I got there and I was good to go. No codes and 1 test not ready.
I've never heard of the fuel level thing. I don't remember how much gas was in the tank at the time. That could be why the test didn't complete right away.
Anyways, I recently had the same problem with my 2000 Civic. On the day of my inspection I used my Autotap to clear the codes and then drive ~3 miles to work. I left work in the afternoon and drove ~40 miles to the inspection station. Within the first 10 miles of the drive all of my readiness tests were complete except for the evap system. Evap did not complete by the time I got there and I was good to go. No codes and 1 test not ready.
I've never heard of the fuel level thing. I don't remember how much gas was in the tank at the time. That could be why the test didn't complete right away.
01-13-2011 | 06:28 PM
#3
Wanted to run this by you guys here to see if anyone had experience or advice. I didn't know of a better fitting section on Tech.
My DD is an '03 Caddy SLS. Been fighting P0440 codes (EVAP large leak) for a couple years. Luckily enough they've gone away the past 2 years when emissions time came. Not so lucky this time and I'm due before the month's end. Yes, I've troubleshot the problem a lot over the years. Replaced the gas cap twice, vent solenoid, and recently the fuel tank pressure sensor. Traced out almost every inch of line from the tank to the purge solenoid, no leaks. I think the culprit is the seal between the pump assembly and tank as there is a good bit of corrosion (NY car) and a faint gas smell. Really don't feel like dropping the tank and replacing. Or paying a shop a bunch of money.
Anyways, as per documentation the EVAP test only runs when the tank is between 15-85% full. If I clear the codes, and keep the tank near full, I assume the EVAP monitor would come up as "Not Ready", however I also believe 2000+ OBD2 cars are allowed one "Not Ready" monitor and can still pass. Think my plan will work?
My DD is an '03 Caddy SLS. Been fighting P0440 codes (EVAP large leak) for a couple years. Luckily enough they've gone away the past 2 years when emissions time came. Not so lucky this time and I'm due before the month's end. Yes, I've troubleshot the problem a lot over the years. Replaced the gas cap twice, vent solenoid, and recently the fuel tank pressure sensor. Traced out almost every inch of line from the tank to the purge solenoid, no leaks. I think the culprit is the seal between the pump assembly and tank as there is a good bit of corrosion (NY car) and a faint gas smell. Really don't feel like dropping the tank and replacing. Or paying a shop a bunch of money.
Anyways, as per documentation the EVAP test only runs when the tank is between 15-85% full. If I clear the codes, and keep the tank near full, I assume the EVAP monitor would come up as "Not Ready", however I also believe 2000+ OBD2 cars are allowed one "Not Ready" monitor and can still pass. Think my plan will work?
Hey I know we went over this a few years ago, but I have seen a trend.
Sniff around the fuel filler door.
Up in Wisconsin I saw a few of the older bodied Deville's and Seville's leaking around the filler neck.
The newer Deville's and Seville's like yours have a plastic fuel filler with a metal piece over then end that the cap atteches to.
I have seen a few issues in this area. I just had one last week I could see light through. I never really saw too much smoke (using the smoke machine), but I could smell it near the cap. I started pulling the rubber seal back and then I could see light shining through.
01-14-2011 | 08:47 AM
#4
Thread Starter
Joined: Jan 2002
Posts: 1,801
Likes: 28
From: Dutchess, New York
Brad, thanks for the input, that's a good sign.
CalEditor, is that AXJ from the Caddy forums? I posted in this section a couple years ago trying to see if it could be disabled via a PCM editor. And yes, I did remember then you mentioned the filler neck. I was looking more at where it coupled with the tank itself. However I'll follow your advice and look at the fill end instead first.
Thanks for the help!
CalEditor, is that AXJ from the Caddy forums? I posted in this section a couple years ago trying to see if it could be disabled via a PCM editor. And yes, I did remember then you mentioned the filler neck. I was looking more at where it coupled with the tank itself. However I'll follow your advice and look at the fill end instead first.
Thanks for the help!
01-14-2011 | 12:33 PM
#5
I just use the "Right Stuff" gasket maker and put a bead around the filler neck where the plastic piece joins to the metal on the outside so no fuel touches it. Been working for over a year on my Grand Prix. It is a very common leak on GM's.
02-08-2012 | 03:22 PM
#6
Thread Starter
Joined: Jan 2002
Posts: 1,801
Likes: 28
From: Dutchess, New York
Been over a year since I made this thread, but I felt it might be useful in the future if anyone is trying to research so let me give an update. I have successfully used this method 2 years now to beat the OBD2 inspection testing. The EVAP problem still persists on my Cadillac and I long since gave up trying to fix it after throwing too many parts and too much of my time at it.
So what you do is fill up the tank and clear the existing code. Then you will need to keep the tank topped off (so it is above the 85% fill) until after you have passed inspection. On the Caddy this meant I had to top it off after about 80 miles before going through another cold start. This will keep the EVAP test from running. You will still need to complete an OBD2 drive cycle so all of the other readiness monitors show complete. Now, you can drain the fuel down past 85% on a single day and not trip the test - the test will only run after the car has sat for quite a few hours, basically overnight. So if you have to drive 100, 200, 300 miles in a day, you can do so without issue.
What I found interesting, is I verified via AutoTap that even doing this, the EVAP readiness monitor will still show as complete (as opposed to not ready which I expected) despite not being able to run the test. Go figure.
So what you do is fill up the tank and clear the existing code. Then you will need to keep the tank topped off (so it is above the 85% fill) until after you have passed inspection. On the Caddy this meant I had to top it off after about 80 miles before going through another cold start. This will keep the EVAP test from running. You will still need to complete an OBD2 drive cycle so all of the other readiness monitors show complete. Now, you can drain the fuel down past 85% on a single day and not trip the test - the test will only run after the car has sat for quite a few hours, basically overnight. So if you have to drive 100, 200, 300 miles in a day, you can do so without issue.
What I found interesting, is I verified via AutoTap that even doing this, the EVAP readiness monitor will still show as complete (as opposed to not ready which I expected) despite not being able to run the test. Go figure.
