First Post..Odd Problem EVAP Pressure...

[kopp3rhead]

aloha to all...

so,,i did a pretty large rebuild on my 99 Hoe after a failed inspection about 4 yrs back...
failed for balljoints, exhaust leak , lic plate light and a snapped wheel stud...

so 4 yrs later,full suspension rebuild, intakes gaskets, and tons more,,,

im at the evap system....

i have an odd leak failure...

No Codes..say whaatt...

when i do an evap system test on a LAUNCH pocket scanner...i gives a leak in the evap...

No Codes....

Tested the solenoid at canister...purge valve...Both bench tests good...

Installing a new press sensor at the tank now...and testing the harness....

so,,til then a couplepics...best payment for free opinions...cheers Tom

 

[kopp3rhead]

yikes,,,
forgot...

5.7,,350 vortec v8..163k....

 

[OR VietVet]

Welcome to the forum from Oregon. I have seen many a thread here about evap systems and typically, after replacing one part at a time, most of the system gets replaced if not the whole system. Good luck diagnosing that system.

 

[kopp3rhead]

and Ahoy for western Mass!

so changed the sensor, harness is OK...

no change, heres some screens of the reader...

 

[kopp3rhead]

ok...
i may be outside my knowledge base,
but,
i think those test modes are not accessable with my tool and instead of signaling non supported modes, instead are giving inconclusive and fail.

 

[97YukonNZ]

Hi and welcome from New Zealand Lol ‍
Nice looking brake n Suspension upgrade. I dont know about ac system yet, no doubt will learn about that should issues arise.
Nice looking rig
Welcome to the forum

 

[Bill 1960]

I am unclear on what symptoms led you to believe there’s an evap problem to begin with? Since there are no codes. Is the MIL on?

If the only indication is the scanner message, then I believe you’re on to something with post #5. Probably just the scanner telling you the bidirectional testing functionality is not supported.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving replies from the knowledgeable folks on this Forum. Others will chime in.

 

[kopp3rhead]

I am unclear on what symptoms led you to believe there’s an evap problem to begin with? Since there are no codes. Is the MIL on?

If the only indication is the scanner message, then I believe you’re on to something with post #5. Probably just the scanner telling you the bidirectional testing functionality is not supported.

thats just it, no CEL,,no MIL...just those oddball fails..and yes to the 2 way communication not being available with the PCM

I have another reader,it shows nothing,,no DTC...

On that one....there Is a 3 LED Emissions scale,Green - Amber - Red...
Amber is illuminated...not good,,not bad,,,just so-so...lol..

so humph....its a scratcher...

 

[Fless]

Can you see if the evap monitor has completed, or is it showing incomplete?

If you're driving it, has it gone through a drive cycle or two? Once the drive cycles are complete, by definition the truck's evap monitor has completed and it will either set the money light, or not. If it lights up, there will be a current code.

I'd be inclined to check the status of the monitors and wait it out a bit, or until they've completed.