Trying to get rid of P0442 - small Evap Leak

[RichardH]

A P0442 leak is actually a pretty good leak in the system. Often a purge valve stuck open, or corrosion pin holes in the filler neck, or bad fuel cap. Do you have access to a mechanics smoke tester ?



https://www.ebay.com/itm/Automotive...413072?hash=item5da8d3d390:g:L~YAAOSwzQpev5m1

Interesting. The literal definition of the code says "small leak" vs other codes. Thanks for the info.

I do not have access to a smoke system, but with the link and at $40 bucks, should direct me on the proper course...

Again - thanks,
Dick

 

[thesavo]

Wow, $40 for a smoke machine? For that price I would buy one preemptively.

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[RichardH]

Wow, $40 for a smoke machine? For that price I would buy one preemptively.

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Sure and you can charge you most annoying friend $20 twice for the test and the part is free!

 

[Kevin Masters]

A P0442 leak is actually a pretty good leak in the system. Often a purge valve stuck open, or corrosion pin holes in the filler neck, or bad fuel cap. Do you have access to a mechanics smoke tester ?



https://www.ebay.com/itm/Automotive...413072?hash=item5da8d3d390:g:L~YAAOSwzQpev5m1

Link doesn’t work.. can you update it?

 

[riphip]

Link was removed by ebay. EBay said was Chinese scam. Got my money back through PayPal.

 

[Hamfisted]

Link was removed by ebay. EBay said was Chinese scam. Got my money back through PayPal.

Wow, that's really crappy. I hadn't bought one in over ten years, I just thought maybe the price had come down on them, or that model. Sorry about that. I updated the link to another seller that must be more legit.


https://www.ebay.com/itm/EVAP-Smoke...883925&hash=item41de9b5320:g:NNkAAOSw~4hbvI1l

 

[tvlunn]

I'll share some information which may be helpful:

1) I'm not sure of your particular model, but I have a 1998 Expedition which I purchased new and has been well maintained through the years. It has a 5.4 engine. Earlier this year I also received a P0442 engine code. I too was hopeful the gas cap was the culprit and purchased a new OEM cap. That did NOT correct the issue!

2) After visually inspecting what EVAP system hoses and tubing could be easily accessed, I could not visually detect any type crack, pinhole or loose connection. I then checked for proper operation of the purge solenoid and vapor canister vent solenoid and found they were functioning and sealing properly.

3) I then realized, as I had already been informed, a smoke machine was likely the only way to detect the cause of the code. So, I purchased a smoke machine. Once I connected the smoke machine to the EVAP system, it only took about 20 minutes to see there was smoke leaking from somewhere on the TOP of the fuel tank …………...…. not what I wanted because that meant, well you know, remove the tank!

4) Once I dropped the tank, I connected the smoke machine to the fuel tank itself and could then easily see where a SMALL amount of smoke was escaping. It was escaping from around the front vapor valve. Close inspection showed a VERY SMALL crack in the plastic or composite fuel tank, just below the hose nipple on the vapor valve.

5) These composite fuel tanks for the older Expeditions are now obsolete and can not be purchased. There was no used tank to be found locally, so I elected to try and repair the crack with JB Weld. That was about 3.5 months ago, and so far, the JB Weld is holding perfectly!

Attached is a photo of the repair. And by the way, the two vapor valves on the composite tank are not replaceable as they are sonic welded in place.

So, unless one of your two solenoids are defective, you have a bad fuel cap, or a leak that can be easily spotted, the use of a smoke machine will likely be required.​

Hope this is helpful!

 

[RichardH]

I'll share some information which may be helpful:

1) I'm not sure of your particular model, but I have a 1998 Expedition which I purchased new and has been well maintained through the years. It has a 5.4 engine. Earlier this year I also received a P0442 engine code. I too was hopeful the gas cap was the culprit and purchased a new OEM cap. That did NOT correct the issue!

2) After visually inspecting what EVAP system hoses and tubing could be easily accessed, I could not visually detect any type crack, pinhole or loose connection. I then checked for proper operation of the purge solenoid and vapor canister vent solenoid and found they were functioning and sealing properly.

3) I then realized, as I had already been informed, a smoke machine was likely the only way to detect the cause of the code. So, I purchased a smoke machine. Once I connected the smoke machine to the EVAP system, it only took about 20 minutes to see there was smoke leaking from somewhere on the TOP of the fuel tank …………...…. not what I wanted because that meant, well you know, remove the tank!

4) Once I dropped the tank, I connected the smoke machine to the fuel tank itself and could then easily see where a SMALL amount of smoke was escaping. It was escaping from around the front vapor valve. Close inspection showed a VERY SMALL crack in the plastic or composite fuel tank, just below the hose nipple on the vapor valve.

5) These composite fuel tanks for the older Expeditions are now obsolete and can not be purchased. There was no used tank to be found locally, so I elected to try and repair the crack with JB Weld. That was about 3.5 months ago, and so far, the JB Weld is holding perfectly!

Attached is a photo of the repair. And by the way, the two vapor valves on the composite tank are not replaceable as they are sonic welded in place.

So, unless one of your two solenoids are defective, you have a bad fuel cap, or a leak that can be easily spotted, the use of a smoke machine will likely be required.​

Hope this is helpful!


View attachment 36183

tvlunn, that is great information - BTW, I have a 2003 EB 5.4 2 wd. 150k miles, runs great. When I bump it into N at red lamp, I can't even feel the engine running - it;'s so smooth! Very small difference in D, but I believe that's normal.

And I am always open to other's experience with this in an effort to cure the issue.

$155 is sort of steep for me until I get back into FT work, possibly in about 3 weeks. I will check with a friend to see if he has one. That seems like the best start to dx'ing the problem.

Here is another quick question (hopefully).

I have a regular not super high end OBDii scanner. It's not showing any stored codes but is showing pending codes w/ P0442. Again, no stored codes and no MIL/CEL lamp illuminated. On checking the live or KOEO data, is reads MIL_DIST 0km/mi. Does that mean I have driven enough miles since erasing codes? It used to show P1000 - must drive more miles.

If this is good to go (GTG) and a pending code won't trigger a FAIL at inspection, it'll be a beeline after I get some feedback. I'm also going to call a different shop than I plan on getting the inspection to see what they say tomorrow AM, but would also appreciate any info from the brain trust here at this forum.

TIA,
Dick

 

[Hamfisted]

Check with some of your local auto parts stores for the smoke machine. I know my local NAPA shop down here has one they rent out.

 

[RichardH]

Check with some of your local auto parts stores for the smoke machine. I know my local NAPA shop down here has one they rent out.

Most definitely! I had that thought in mind to check w/ Auto Zone this morning, I'll look for a local Napa - thanks. Was also looking at Amazon this morning, those machines are kind of expensive...

Dick