EVAP I/M Readiness is Going to Be the Death of Me! - Somewhat Solved - Still Alive

[Kwing]

Registration for my '07 Tahoe 5.3 expires on the 15th (10 days). I got the HP tuner to disable my AFM so I could remove the bypass dongle, which worked great, but uncovered some misfire issues.

The entire right bank had to be rewired from the branch at the back of the intake forward (so all 4 coil packs, all 4 injectors, ground to head, and the TPS). I had to build the harness from scratch. Puts the F-U in fun.

Once that was done, it exposed a bad TPS, so I replaced the entire throttle body.

That was 3 weeks ago.

I have attempted to run the standard I/M readiness drive cycle (cold start, idle 2.5 min, 50% throttle to 55 mph, hold 3 minutes, deccel to 20 without brakes, 75% throttle to 55, hold 5 minutes, deccel to 20 again) 3 times in that span. EVAP still reads INC.

Best guess I got is that I either suck or the ambient temp in Phoenix isn't even dipping below the 86F max allowed start temp.

I found another proceedure that claims it doesn't require the cold start (hold steady speed between 30 and 60 mph for 5 minutes, followed by 4 minutes of idling, then shut off and remove the key. 0 for 5 on that one.

My head hurts from pounding against the wall at this point, LOL.

Anyone know how to get this pig to roll over from INC to OK?

 

[swathdiver]

Registration for my '07 Tahoe 5.3 expires on the 15th (10 days). I got the HP tuner to disable my AFM so I could remove the bypass dongle, which worked great, but uncovered some misfire issues.

The entire right bank had to be rewired from the branch at the back of the intake forward (so all 4 coil packs, all 4 injectors, ground to head, and the TPS). I had to build the harness from scratch. Puts the F-U in fun.

Once that was done, it exposed a bad TPS, so I replaced the entire throttle body.

That was 3 weeks ago.

I have attempted to run the standard I/M readiness drive cycle (cold start, idle 2.5 min, 50% throttle to 55 mph, hold 3 minutes, deccel to 20 without brakes, 75% throttle to 55, hold 5 minutes, deccel to 20 again) 3 times in that span. EVAP still reads INC.

Best guess I got is that I either suck or the ambient temp in Phoenix isn't even dipping below the 86F max allowed start temp.

I found another proceedure that claims it doesn't require the cold start (hold steady speed between 30 and 60 mph for 5 minutes, followed by 4 minutes of idling, then shut off and remove the key. 0 for 5 on that one.

My head hurts from pounding against the wall at this point, LOL.

Anyone know how to get this pig to roll over from INC to OK?

So are you DTC free at this point? No codes in the engine or chassis modules?

How many miles have you driven and what kind of fuel are you burning?

 

[Marky Dissod]

How close can you keep the fuel tank to 1/2 full? Between 5/8 & 3/8 full is best.
On a very full or nearly empty tank, the EVAP does not behave the same as when it is between 3/8 & 5/8 full.

 

[Doubeleive]

Registration for my '07 Tahoe 5.3 expires on the 15th (10 days). I got the HP tuner to disable my AFM so I could remove the bypass dongle, which worked great, but uncovered some misfire issues.

The entire right bank had to be rewired from the branch at the back of the intake forward (so all 4 coil packs, all 4 injectors, ground to head, and the TPS). I had to build the harness from scratch. Puts the F-U in fun.

Once that was done, it exposed a bad TPS, so I replaced the entire throttle body.

That was 3 weeks ago.

I have attempted to run the standard I/M readiness drive cycle (cold start, idle 2.5 min, 50% throttle to 55 mph, hold 3 minutes, deccel to 20 without brakes, 75% throttle to 55, hold 5 minutes, deccel to 20 again) 3 times in that span. EVAP still reads INC.

Best guess I got is that I either suck or the ambient temp in Phoenix isn't even dipping below the 86F max allowed start temp.

I found another proceedure that claims it doesn't require the cold start (hold steady speed between 30 and 60 mph for 5 minutes, followed by 4 minutes of idling, then shut off and remove the key. 0 for 5 on that one.

My head hurts from pounding against the wall at this point, LOL.

Anyone know how to get this pig to roll over from INC to OK?

if the only one "not ready" is evap then you are good to go, AZ allows one im not ready on 2001 and newer. that thing could take a month to set

 

[Fless]

Seems like you have the list of requirements to start, but be sure to check the ECT and IAT values before starting so they're not far apart. I think it's slightly less than 11°F.

 

[Kwing]

So are you DTC free at this point? No codes in the engine or chassis modules?

How many miles have you driven and what kind of fuel are you burning?

Correct, DTC free on both modules, all systems N/A or OK except EVAP at INC. I'm at about 500 miles since the last code clearing, running 87 octane at whatever garbage ethanol blend AZ has this time of year.

How close can you keep the fuel tank to 1/2 full? Between 5/8 & 3/8 full is best.
On a very full or nearly empty tank, the EVAP does not behave the same as when it is between 3/8 & 5/8 full.

The instructions I found said 1/4 to 3/4 were the boundaries, which I was inside of, but I wasn't mentally recording in any higher resolution than that... although I can tell you this morning's attempt was just a shade under 3/4.

Seems like you have the list of requirements to start, but be sure to check the ECT and IAT values before starting so they're not far apart. I think it's slightly less than 11°F.

Interesting. I found where delta between ECT to ambient had to be within 11F, but was unaware ambient was recorded at IAT. I was considering a bag of ice at the ECT sender, but passed on it because of the ambient condition. If it's IAT, I may still have that option...

if the only one "not ready" is evap then you are good to go, AZ allows one im not ready on 2001 and newer. that thing could take a month to set

Son of a #^(<!~&_[!*(#, LOL. I thought they ALL had to be ready! I feel dumber than normal. I'm gonna go down there in the morning. If it passes, my wife ain't never gonna let me live this down, LOL.

I'll report back in the AM. Thanks for all the suggestions everyone!

 

[swathdiver]

Correct, DTC free on both modules, all systems N/A or OK except EVAP at INC. I'm at about 500 miles since the last code clearing, running 87 octane at whatever garbage ethanol blend AZ has this time of year.


The instructions I found said 1/4 to 3/4 were the boundaries, which I was inside of, but I wasn't mentally recording in any higher resolution than that... although I can tell you this morning's attempt was just a shade under 3/4.


Interesting. I found where delta between ECT to ambient had to be within 11F, but was unaware ambient was recorded at IAT. I was considering a bag of ice at the ECT sender, but passed on it because of the ambient condition. If it's IAT, I may still have that option...


Son of a #^(<!~&_[!*(#, LOL. I thought they ALL had to be ready! I feel dumber than normal. I'm gonna go down there in the morning. If it passes, my wife ain't never gonna let me live this down, LOL.

I'll report back in the AM. Thanks for all the suggestions everyone!

Well, if she doesn't pass, run 91 or 93 until she does pass.

 

[Fless]

The instructions I found said 1/4 to 3/4 were the boundaries, which I was inside of, but I wasn't mentally recording in any higher resolution than that... although I can tell you this morning's attempt was just a shade under 3/4.

Good luck on it passing -- you have a good chance of that.

Technically the evap spec for fuel level is 1/8 to 7/8 full, but since we have to rely on somewhat inaccurate (imprecise) readings from senders and gauges, a lot of documentation will say 1/4 to 3/4. When the evap test runs and the system is sealed, the tank pressure changes based on the fuel temp vs ambient, so that's taken into consideration.

 

[Kwing]

Ya know, sometimes I impress myself with how stupid I can be!

It passed with the EVAP still at INC.

All that and I could have been done with this 2 weeks ago, LOL.

Thanks again for all the advice!

 

[j91z28d1]

very good to hear.