Evap repair (3rd time's the charm?)

Jayne

Just here for the memes
Charter Member
Supporting Member
Multi-Factor Enabled
Joined
Dec 16, 2016
Messages
8,028
Location
Unincorporated Wake County
Rating - 100%
34   0   0
My '06 1500 5.3L has been throwing the P0455 code for a while. "Tighten gas cap", but of course that's not really the issue. I've replaced the cap, the purge valve and vent valve solenoid because those are things google seems to say are probable causes and reasonably cheap to do myself. None of that has helped.

Lore seems to indicate that a 'smoke test' is the next step to find out what line somewhere is cracked and leaking. Makes sense, but it's not like I have the equipment around to do that so the next step is to take it to an actual mechanic.

It's been a long time since I've taken a vehicle to a mechanic without anything specific to fix (ie my transmission is dead). How bad is it out there now, will they take what I've done and move onto the next step in the diagnostic or are they going to insist on replacing the parts I've replaced before they'll do anything with it?

And another fun question, is this a dealer issue since it's some BS emissions thing and not an actual mechanical problem?
 
I've been to Cary Car Care for 26 years and found them to be extremely honest. Not the cheapest, but straightforward, and stand behind their work. E. Johnson Street near National Guns and Gear. 919-380-0040
 
As info...I tried the DIY smoke test with a fog machine, and it simply turned to condensation before exiting any hole.

Ended up finding a cracked elbow after checking all the vacuum lines I could get my hands on.
 
You can use a bottle and a cigeratte to make a smoke machine.

Probably a vacuum line to be honest.
 
I'd go hand over hand , On the return line / overflow from the gas filler neck back to the tank.
You'll have to pull the bed bolts and the filler neck and lift one side to get to the top of the tank.
filler-neck_6.jpg

filler-neck_6.jpg
 
P0455 is just telling you what department has a fault. Not what the fault is. Smoke can show if you have a small to large evap leak.
The pcm data will tell you if the evap vent solenoid or evap canister solenoid is working. The data can also show if the fuel tank pressure sensor is working.

Gas cap seal by the big oring but also vent thru small valve internally. Aftermarket gas caps are crap. Go Factory on those and evap solenoids

We get $68.00 to properly diagnose problems/issues. How much has been spent on guessing?
 
We get $68.00 to properly diagnose problems/issues. How much has been spent on guessing?

I'm in it about $40, plus my time. No wait, maybe $55, forgot the cost of the factory gas cap.

I'm just so used to how they do things in CA. They change 1 part, send you on your way, problem comes back, they charge you to fix the next part, send you on your way... etc... etc. Guessing and replacing cheap parts on my own saves hundreds in diag charges and hundreds more in parts at full list + 20%.

That damn state has scared me for life.
 
I'm in it about $40, plus my time. No wait, maybe $55, forgot the cost of the factory gas cap.

I'm just so used to how they do things in CA. They change 1 part, send you on your way, problem comes back, they charge you to fix the next part, send you on your way... etc... etc. Guessing and replacing cheap parts on my own saves hundreds in diag charges and hundreds more in parts at full list + 20%.

That damn state has scared me for life.

If I worked like that, out of business in a month.

Get ahold of a reputable independent non franchise shop.
 
I have a similar fault code on my LeSabre. The fix, so far, as been to push the "Reset" button every time the "Loose gas cap" warning pops up whenever I first start my car.

The most likely problem, according to research on my car, is a leak somewhere around the gas cap to the tank. And it's probably not going to be a cheap fix to replace the parts I need. I'm thinking, if I ever get around to hand-over-hand inspecting this, that I may just try to seal the leak myself instead of replacing the full neck, or whatever.

Mike Overlay has a good point in post #6...namely how much it costs to have something diagnosed. It really boils down to how much your time is worth to you. If you're going to have to spend all afternoon under your vehicle trying to figure this out, it might be worth $60 to have someone else look at it while you do something else...like, say, fishing.

Here's my advice on this:

I found out from a dealership once that whether you bring your car in to have one problem diagnosed or a dozen problems...the price is the same. So make a list of issues you want them to look at whenever you take your vehicle in. Want a Check Engine fault diagnosed? Fine. Have them check out what's causing that minor shimmy at certain speeds, the Freon leak you put up with because winter hit and you didn't need A/C then, that stupid blinker problem, etc. They'll tell you what they found and what it'll take to repair it. You can then make the decision what to have them repair and what you will repair yourself.
 
I've been to Cary Car Care for 26 years and found them to be extremely honest. Not the cheapest, but straightforward, and stand behind their work. E. Johnson Street near National Guns and Gear. 919-380-0040
I worked there about 15 years ago.
 
A smoke test of the evap system is needed. It needs to be done while vehicle is hooked up to a scanner so the technician can control the purge solenoid and the canister vent valve. Also the pins on the connector on the canister vent valve like to push out of he connector also. Ran across this a few times.
 
So is a smoke test sorta like spraying carb cleaner or either on and around suspected vacuum leaks?

I can still remember when I could actually hear vacuum leaks...... tinnitus ... just one more issue with getting older wiser I suppose.
 
Hers a good video of a homemade smoke machine. Just disregard his political sign and enjoy.



Now what will I do with the smoke?
Hook it to a line and watch for smoke? is it that simple?

EDIT: OK a little more u tube googling found this guy.



Can't believe I've been turning wrenches for .. lets just say a long time and didn't ever hear about this ... da##i7.
 
Last edited:
A smoke test of the evap system is needed. It needs to be done while vehicle is hooked up to a scanner so the technician can control the purge solenoid and the canister vent valve. Also the pins on the connector on the canister vent valve like to push out of he connector also. Ran across this a few times.

Yea, I've just been side tracked with a bunch of family nonsense and haven't been able to circle back to working on the truck. It still runs and tows fine, so it keeps getting lowered in priority.
 
P0455 is just telling you what department has a fault. Not what the fault is. Smoke can show if you have a small to large evap leak.
The pcm data will tell you if the evap vent solenoid or evap canister solenoid is working. The data can also show if the fuel tank pressure sensor is working.

Gas cap seal by the big oring but also vent thru small valve internally. Aftermarket gas caps are crap. Go Factory on those and evap solenoids

We get $68.00 to properly diagnose problems/issues. How much has been spent on guessing?

Would that you were in Raleigh... I'd pay you $68 to save me the hassle every time... No one is that cheap around here...
 
I have a similar fault code on my LeSabre. The fix, so far, as been to push the "Reset" button every time the "Loose gas cap" warning pops up whenever I first start my car.

The most likely problem, according to research on my car, is a leak somewhere around the gas cap to the tank. And it's probably not going to be a cheap fix to replace the parts I need. I'm thinking, if I ever get around to hand-over-hand inspecting this, that I may just try to seal the leak myself instead of replacing the full neck, or whatever.

Mike Overlay has a good point in post #6...namely how much it costs to have something diagnosed. It really boils down to how much your time is worth to you. If you're going to have to spend all afternoon under your vehicle trying to figure this out, it might be worth $60 to have someone else look at it while you do something else...like, say, fishing.

Here's my advice on this:

I found out from a dealership once that whether you bring your car in to have one problem diagnosed or a dozen problems...the price is the same. So make a list of issues you want them to look at whenever you take your vehicle in. Want a Check Engine fault diagnosed? Fine. Have them check out what's causing that minor shimmy at certain speeds, the Freon leak you put up with because winter hit and you didn't need A/C then, that stupid blinker problem, etc. They'll tell you what they found and what it'll take to repair it. You can then make the decision what to have them repair and what you will repair yourself.
Not all stealerships are like this. The dealership I used to work at charged a diag fee per complaint. Best to ask first.
 
Finally got a chance to make an appointment and take the truck in. Ended up going to Ten Ten automotive based on reviews and research. That place is packed, so although annoying it's a really good sign.

I told them what I had done, and they said they would take a look. Up on the lift it took them minutes to find the leak, some rodent like creature had chewed through the line up on top of the tank where I could not see. He saved my ego by saying it was easy to see if you could get your head up in there, but not so much if you didn't have the lift.

He said that I seemed like the type who would want to do it myself, gave me the part number to order and said I should just order it up and install it, or they could if I didn't want to bother. I'm a cheap ass, so of course I want to order the parts myself and do it since they did the part I couldn't.

I went to settle up the bill and get on my way... and he wouldn't even charge me! I kept saying "you did the work, take the money" but he just told me to come back when I had other stuff to do. So there ya go.

evap_hose_1.jpeg

The hose itself was $46 on amazon, but I figured I would try local first. I was showing a neighbor the part before heading out.... and we wondered if we could just fix it with some fuel line? It's not high pressure or anything.... so 2" of fuel line scrap later it's back in business. If it doesn't work, replacing it with the factory part is trivial.

evap_hose_2.jpeg
 
I've heard good things about them before.
 
Jayne something similar happen to my '84 F150 a couple years ago. Was headed hunting and stop to get gas and smelled gas. Looked underneath and had gas pouring. Was very near the shop where I work so I took a stupid chance and drove it there. Found the same thing on the fuel return line over the tank. I guess the little bastard sat comfortably on the tank as he chewed. I repaired mine the same way and so far it has not leaked.
 
Finally got a chance to make an appointment and take the truck in. Ended up going to Ten Ten automotive based on reviews and research. That place is packed, so although annoying it's a really good sign.

I told them what I had done, and they said they would take a look. Up on the lift it took them minutes to find the leak, some rodent like creature had chewed through the line up on top of the tank where I could not see. He saved my ego by saying it was easy to see if you could get your head up in there, but not so much if you didn't have the lift.

He said that I seemed like the type who would want to do it myself, gave me the part number to order and said I should just order it up and install it, or they could if I didn't want to bother. I'm a cheap ass, so of course I want to order the parts myself and do it since they did the part I couldn't.

I went to settle up the bill and get on my way... and he wouldn't even charge me! I kept saying "you did the work, take the money" but he just told me to come back when I had other stuff to do. So there ya go.

View attachment 12747

The hose itself was $46 on amazon, but I figured I would try local first. I was showing a neighbor the part before heading out.... and we wondered if we could just fix it with some fuel line? It's not high pressure or anything.... so 2" of fuel line scrap later it's back in business. If it doesn't work, replacing it with the factory part is trivial.

View attachment 12748
I noticed you carried feed or something like that in the back of your truck it was all over the top of your tank. That is probably what attracted them. Funny thing about squirrels they like to chew on fuel tanks and gas caps.
 
Last edited:
I noticed you carried feed or something like that in the back of your truck it was all over the top of your tank. That is probably what attracted them. Funny thing about squirrels they like to chew on fuel tanks and gas caps.

The truck mostly hauls pine shavings, gravel and hay, and the shavings are sorta everywhere. I'm sure he had a nice little pine bed setup in there and just decided to taste the hoses. Little bastard.

The only thing good that's come out of this is the wife saying "maybe we should park the truck in the garage"? If she puts her car in the carport and lets me move the truck inside... it will all be worth it. :)
 
If she puts her car in the carport and lets me move the truck inside... it will all be worth it.

Until you have to work on her car! Isn't that the same thing as putting fresh food out for El Rodento? :)

Seriously, though--glad you had a happy automotive ending. Maybe I'll drive to Top Ten sometime...
 
Until you have to work on her car! Isn't that the same thing as putting fresh food out for El Rodento? :)

The truck sits most of the time, her car would move every day ensuring that any camping rodents would move along. That's the theory anyway.
 
Put some miles on the truck yesterday, and the "tighten gas cap" message came back and then the CEL came on a little while later. Looks like the smoking gun was only one of the culprits. A second gunman on the grassy knoll? Sigh.
 
Dang. Nice shop..Wish I knew of one like that around Midland.
A & B Automotive in Stallings is the best around & honest as the day is long. Earls techs have been with him for years & he takes care of them. I did all my work for many years until i got tired of laying on concrete not to mention I can barely get back up from that concrete.
 
Shop knows how to take care of their customers.
You did him a favor, he can work on more serious repairs.
 
Last edited:
Put some miles on the truck yesterday, and the "tighten gas cap" message came back and then the CEL came on a little while later. Looks like the smoking gun was only one of the culprits. A second gunman on the grassy knoll? Sigh.
Bring it back on by and we will see what it is. I was afraid some of thoose shavings might have been sucked into the system or there is another hole on top of the tank where we can't see it. Just call and set up a time that works for you.
 
Last edited:
First up I'm going to order the part. Many people question the quality of the hack and since it's not a SHTF scenario I can still use amazon to solve problems.
 
Bring it back on by and we will see what it is. I was afraid some of thoose shavings might have been sucked into the system or there is another hole on top of the tank where we can't see it. Just call and set up a time that works for you.

I made a solid effort to try to find any other leaks in that area but nothing was obvious. It will probably be two weeks or so, gotta find another day I can take off to get down there.
 
New hose installed this morning and I went to clear the CEL to see if it returns and notice I now have two codes. 0442 "small leak" is also popping up. Maybe the small leak was being masked by the massive leak? Time will tell.

Also, and this is just an annoyance at GM, but the hose didn't come with one of the necessary fragile plastic sure to fail over time clips that was required. I was able to get the original one off the old hose, but why they couldn't include the proper 1 cent plastic clip on the $42 piece of hose just shows how shitty of a company they really are. The whole point of buying overpriced OEM parts is to ensure 100% correct fitment.
 
Tagged for the same issue with mine.

Sent from my SM-G930P using Tapatalk
 
Two more issues found, at least one required lifting the bed up (easier than dropping the tank I suppose). The charcoal canister had been chewed through in a couple of places behind the cover plate, and one of the hoses on top of the tank that leads to the filler neck had been eaten. Some time off work and a low-end AR worth of parts and labor and we're back on the road.

evap_can_1.jpg
 
I have never seen that much rodent damage done to one car before. I would put out some rat poision you have some hungry varmints. They will eat your whole truck by this time next year if you do not get them first.
 
Last edited:
Back
Top Bottom