Honda Accord Gas Cap - Fix Check Engine Code?

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My friends '98 Accord LX 2.3L 4 banger, 140K keeps throwing an evap check engine light for the gas cap. About every 300 miles or so.
I've heard the OE Honda cap is the fix; I think they are like $60?

Please advise; I appreciate your thoughts.
 
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A new cap for the vehicle is like $6 max on Rock Auto:

https://www.rockauto.com/en/catalog/honda,1998,accord,2.3l+l4,1315583,fuel+&+air,fuel+tank+cap,5900

The cap has an o-ring which seals the cap and tank. Look at the filler neck and identify where the o ring contacts the inside of the neck. Look for rust or other crap which may cause the o ring to not seat correctly. If the sealing surface is rusty, it needs to be cleaned well. I'd use a rag and brake cleaner on it and clean it until the surface finish is uniform without any surface roughness.
If that doesn't help, then you have other leak issues in your system that needs to be diagnosed.
 
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my 99 accord does the same thing...the light is on at times but usually stays off longer right after i fill up...i was told it's the gas cap but not willing to pay $60 so i live will an intermittent check engine light
 
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Same thing happened to my friend's. Have to go to the Honda dealership and get an oem cap.
For only $2.84 he can get an aftermarket cap, bummer is the shipping is more that the cap at $4.99.. So yeah, paying 12$ which is 1/6 of the price of the cap isn't worth it.
I hope it fixes the evap leak... Does the code specifically indicate that the leak is from the fuel cap? One of my older cars, a '96 buick had an actual code for the gas cap, the code literally said gas cap leak, or something like that.
 

JeffKeryk

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A new cap for the vehicle is like $6 max on Rock Auto:

https://www.rockauto.com/en/catalog/honda,1998,accord,2.3l+l4,1315583,fuel+&+air,fuel+tank+cap,5900

The cap has an o-ring which seals the cap and tank. Look at the filler neck and identify where the o ring contacts the inside of the neck. Look for rust or other crap which may cause the o ring to not seat correctly. If the sealing surface is rusty, it needs to be cleaned well. I'd use a rag and brake cleaner on it and clean it until the surface finish is uniform without any surface roughness.
If that doesn't help, then you have other leak issues in your system that needs to be diagnosed.
There is a new Stant cap on it now. The car has never been out of CA; it is in excellent shape otherwise.
I think I have to bite the bullet and buy a Honda cap.
 
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My friend's Accord is a 94. Wonder if it's basically the same as yours Jeff? His indy mechanic actually told him he had to use a Honda oem cap when he showed up at his garage to inquire about the dash light.
 
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There is a new Stant cap on it now. The car has never been out of CA; it is in excellent shape otherwise.
I think I have to bite the bullet and buy a Honda cap.
Yup, that stinks. Have you checked the o-ring mating surface on the fuel filler neck for rust or corrosion that can affect the sealing ability of the o ring on the cap?
And yes, looks like you're getting a new OE cap.
 
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I sold a car at a discounted rate to a gentlemen who beat me down because of an evap leak code.. I tried a new cap, figured it was a gremlin I didn't care to track down because the light didn't bother me. He paid for the car and said to me "watch this".. He removed the gas cap and used a rag and cleaned around the mating surface of the filler neck... Started car back up and light was off. He took pleasure in rubbing it in my face brutally. What a ****. So now I check my fuel neck o-ring mating surface for corrosion with a flashlight about once a year while or so while getting gas. I've never had any issues with evap leaks (thank god) since then.
 
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I have to change the gas cap for a P0171 in my Highlander.
I opt for an OE from stealership around $25.
The CEL turn off by itself.

It happened 2 times after filling up the gas so I figure it was the cap.
 
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I have similar problem with a Hyundai. I looked at the design of the cap and the seal. I also have a spare cap off of some other car and I noticed they basically the same. The seal is not an O ring, more of a C or U shape being open on one side. The threads of the cap have a stop so when you tighten the cap all the way it stops on the threads not the seal. My local parts store has assorted O rings and I am thinking of buying a thin Oring that will fit inside the original C or U seal to make it effectively thicker and seal better when the cap threads hit their stop.
I believe Hank is correct about corrosion.
 
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I had the same problem with my '12.
I took some sil-glyde and rubbed it into the ring on the cap.
For good measure, I sprayed heck out of the inside of the cap with silicone spray.
After making sure the fuel neck was clean, I put the cap back on.
No problems since. The thread that I started should be on this site somewhere.
 
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I have to change the gas cap for a P0171 in my Highlander.
I opt for an OE from stealership around $25.
The CEL turn off by itself.

It happened 2 times after filling up the gas so I figure it was the cap.
A P0171 cannot be fixed by a gas cap replacement. A P0171 is a lean code.
 
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Evap leaks can have many causes, if the cap doesnt turn the money light off it is time for a smoke test. Always use an OE cap, no exceptions. Aftermarket radiator and gas caps are not worth a pee hole in the snow.
 

JeffKeryk

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Evap leaks can have many causes, if the cap doesnt turn the money light off it is time for a smoke test. Always use an OE cap, no exceptions. Aftermarket radiator and gas caps are not worth a pee hole in the snow.
Some things ain't right. $6 or $10 for a gas cap is expensive if it is no good.
Now don't get me started on bogus Amazon NGK spark plugs... Sheesh!

Slap me in the face if ya don't like me, but fake plugs? That's a low blow.
 
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Girlfriend's Honda weekly lit the check engine warning light. Ordered a Gates gas cap from Amazon for under $4. Installed the Gates cap and instructed her to turn the gas cap until she heard 3-4 clicks after the attendant pumped her gas. Solved the problem of the weekly check engine warning light. Reinstalled the OEM cap and had her continue to turn the gas cap after filling. No problems with the OEM cap.

I think the problem is that gas station employees aren't instructed the proper way to tighten the cap down after filling. To test the theory I went to the gas station she uses to refuel. I didn't touch the cap after the attendant replaced it. Within 10 miles my check engine light lit. I re-tightened the cap. It took about 25 miles for the check engine light to go out. Just my experience.
 
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