2005 4.2 P0455 Code

[Petnatcar]

Hi Guys,
The engine has been throwing this code for the past 3 months.
I've got a new Gas Cap and Filler Pipe because that was rusted and after the last code I changed the Purge Valve,
but the code popped on again to day.
The shop has "smoked" the engine and that's how they found the rusted filler pipe but now this again...?

Any thoughts on what is going on here?
The engine still runs great but I can't get rid of that effing code.

Thanks for your help,
Peter

 

[mrrsm]

 

[Petnatcar]

Thanks for the video.
I'll keep you posted as to how this turns out next week.
I used to do my own repairs but unfortunately it ain't so easy after you hit 74.
Have you replaced a steering rack ? That's an interesting exercise.
Regards,
Peter

 

[Realism]

Hi Guys,
The engine has been throwing this code for the past 3 months.
I've got a new Gas Cap and Filler Pipe because that was rusted and after the last code I changed the Purge Valve,
but the code popped on again to day.
The shop has "smoked" the engine and that's how they found the rusted filler pipe but now this again...?

Any thoughts on what is going on here?
The engine still runs great but I can't get rid of that effing code.

Thanks for your help,
Peter

ahh, the large evap code. Dealt with that a lot myself, makes it hard for emissions testing to pass even though it doesnt do anything. IIRC it has to do with back pressure and the very end of the fill pipe, something about a flaw in the manufacturing. Used to get it like clockwork everytime it heated up and would go away during cold months.
When you are filling your tank, does the fuel handle click off if you hold it full open during a fill?
I accidently over filled a number of times during the winter, and then come summer, never got a code and it stayed away.
Makes me wonder if tank expansion during summer was drawing in just enough air in the fill pipe corner to set off the code

 

[Mooseman]

Check the tank's filler neck for evidence of leakage. Although your year wasn't affected by 2002's EXT tank recall, there have been some others that have been affected, maybe because of age or having been jostled while replacing the filler pipe.

Another possibility is that the top of the pump module has rusted through. Happens a lot in the rust belt.

Another smoke test should be able to find the leak.

 

[Petnatcar]

Check the tank's filler neck for evidence of leakage. Although your year wasn't affected by 2002's EXT tank recall, there have been some others that have been affected, maybe because of age or having been jostled while replacing the filler pipe.

Another possibility is that the top of the pump module has rusted through. Happens a lot in the rust belt.

Another smoke test should be able to find the leak.

Hi Moose,
I replaced the Fuel Tank, Fuel Pump, Lock Ring and Seals last November when the code initially kicked on.
I replaced the Filler Pipe in September after the first Smoke Test but the code kicked back on.
Then I replaced the OEM $50 Gas Cap 2 weeks ago with no effect and the code popped again.
Last week I replaced the Purge Valve on the side of the engine but
the CEL came on after 45 miles.
By the looks of the schematic the only components left are the Canister, the Vent Valve and Pressure Valve ?
I'm taking it in tomorrow for another Smoke Test and will keep you posted.
Thanks again,
Peter

 

[Petnatcar]

ahh, the large evap code. Dealt with that a lot myself, makes it hard for emissions testing to pass even though it doesnt do anything. IIRC it has to do with back pressure and the very end of the fill pipe, something about a flaw in the manufacturing. Used to get it like clockwork everytime it heated up and would go away during cold months.
When you are filling your tank, does the fuel handle click off if you hold it full open during a fill?
I accidently over filled a number of times during the winter, and then come summer, never got a code and it stayed away.
Makes me wonder if tank expansion during summer was drawing in just enough air in the fill pipe corner to set off the code

Realism,
Never had any problems at the gas pump, always a good steady flow but
I'll bring your suggestions to the attention of the guys at the shop tomorrow
when they run another Smoke Test?
This has been a good truck since I got it in 2017 with 93,000 mi. but it's seen some hard winters
and I know things will wear out, but I think they can all be fixed and it's gotta be cheaper then buying a new car which I can't afford.
Thanks,
Peter

 

[Mooseman]

I know it usually comes with the new pump but what about the tank pressure sensor? Maybe it's not inserted correctly or it's defective, always showing 0 or low pressure. There are tests to check this but require an advanced scanner.

 

[Petnatcar]

I know it usually comes with the new pump but what about the tank pressure sensor? Maybe it's not inserted correctly or it's defective, always showing 0 or low pressure. There are tests to check this but require an advanced scanner.

Moose,
The new pump was installed last November and the engine runs perfectly so I hope it's not the Pressure Sensor. I can't help think it's a dried out rubber hose ?
I realize this EVAP business has nothing to do with engine performance but it sure is a pain in the ass.
The guys at the shop say the computer shows a big leak but not where it's located, thus the second Smoke Test, but shouldn't they have seen all the leaks on the first Smoke Test?
The Filler Pipe was replaced after that test but nothing else and yet the code keeps coming back?

Thanks,
Peter

 

[Mooseman]

Could have been two leaks but because of the rusted through filler, that's what was most evident and focused on. Who knows. Maybe also a misinstalled pump seal. The smoke should make it evident again.

 

[Petnatcar]

That's what I'm hoping.

 

[59840Surfer]

The concept of a "pressure sensor" here is a failure to understand the real purpose in the evaporative fuel capture systems sensor --- ultimately and for our purposes of discussion here ---- it's actually the operation as a "vacuum sensor" to which we are in this discussion.

There should NEVER BE any pressure allowed to build in a fuel tank --- although there's ultimately an auxiliary/secondary fail-safe pressure blow-off provision --- if designed baseline pressure values should be exceeded; smog-be-to-hell.

THINK for a moment --- how safe would it be to allow fuel in a plastic tank to be pressurized?
ANSWER - it's not very safe nor intelligent --- and the attorneys would be rubbing their wallets all the way to the courthouses filing lawsuits 24/7.

MOST times --- during a hot-soak over asphalt and a cold tank of fuel --- if allowed to sit long enough, will create some pressure which is then directed to the activated carbon vapor can, so it can be burned off when the engine is running, later on.

On SOME systems, there is even a secondary pressure dump valve --- just in case the carbon canister becomes fully saturated --- but by then, there's a lot of codes-a-blinking.

The bi-directional piezo-sensor is really testing the amount of vacuum as the FedEPA stipulates --- and should be a certain value after the engine has run and a certain level of OBD-Readiness has been established.

If that value cannot be achieved, then the CEL fires up after a certain qualifier "event-count" happens and you've got a code to investigate.

 

[Petnatcar]

So what is the secret to keeping this system air tight?
I've changed most of the components but no rubber hoses or hard lines yet.
I'm hoping the smoke test can zero in on the leak.

 

[Petnatcar]

Hi Guys,
It looks like the shop made a mistake when they connected the Filler Pipe which resulted in the vacuum leak.
I think there is a small rubber or plastic vent hose connected to the Filler Pipe that has a snap-on connector that wasn't tightened properly.
The Smoke Test brought that to their attention but best of all they didn't charge me !
I'm still in the cycle stage but I hope the CEL stays off. I'II BE BACK !

Peter Carbone