Novak Conversions Jeep Wrangler TJ engine mounts

What I learned fixing an evap leak

Tin Man

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Oct 28, 2020
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Georgia
My 2002 was throwing a code for an evap leak. I replaced the fuel cap and all of the fittings I could see in the engine bay. Still got the code. I learned it is super helpful to have a smoke test kit. Once I had that, I found the fittings at the fuel tank were leaking heavily.

Once I dropped the tank I found the Y connector that connects the evap lines was broken. This is a 1/4 X 1/4 X 3/16. I also found that I could not find this connector anywhere locally, so I used a 1/4 X 1/4 X 1/4 brass fitting that I found at the hardware store. I am sure there are other options out there as well as brass, but that is what I found. I was able to attach a piece of 3/16" hose to the 1/4" fitting and that seems to work. I also found a 1/4" to 3/16" reducer nipple that I was going to use, but it worked without it, so I figured less fittings is better. I also had a leak from one of the rollover valve nipples, but it turned out it was just the hose. Once I put a new 1/4" hose on it, there was no leak.

Here is the biggest thing I learned. The gas tank with over half a tank of gas in it is heavy. I knew it would be, but if I had to do it again, I would wait until it was damn near empty before I pulled it. I used an ATV jack to lift it up while I pulled the nuts, and then I used the ATV jack to slowly lower it to do the work. The same jack worked well to put it back in place, but there is a certain amount of wiggling that has to be done to line up all of the bolts. This would have been much easier if the tank was closer to empty. In hindsight, I have a pump and could have emptied the tank, I was just too lazy to empty it and figured I would fight with it. In hindsight, it would have been faster to empty it and my shoulders would hurt less this morning.

Lastly, I found 2-3 other very small pinhole leaks in the top of the tank. I just decided to leave them alone (mostly) for now. I am not sure if they are big enough to throw a code. I guess I will find out. I did have some clear silicone caulk, so I brushed and cleaned the areas and smeared some of that on there. I am reasonably sure that fix is temporary at best. My other option was duct tape, maybe I should have used both. I am going to see if I can find a decent used tank locally or I may pick up a plastic welding setup and try that. Dropping the tank should be a bit easier next time. The bolts and nuts I used are new and won't need to be cut off. I should be able to drop the tank with less gas in it, drag it to my driveway and give it a good cleaning as well. The thing is nasty and the straps need to be replaced. Once I have the parts and stuff I need, I will tear it off again.

As I was working on this system it made me wonder why I couldn't bypass the gas tank in the evap system. I realize it would essentially remove the entire reason for having the evap system and it would vent fuel vapor to the atmosphere. I would imagine if I tied the two 1/4" hoses from the rollover valves to each other it would seal the system and not throw a code. The tank would vent out of the rollover vents and would possibly cause a fuel smell in the cab. May also not pass emissions, but I don't have emissions testing here. Anyway, anyone ever bypassed the tank?

That's all I got, fun project. Seemed daunting at first, but the only hard part was dealing with the heavy ass gas tank.

Tin Man
 
Thanks for that. I will look into it. My shoulders will need to recover before I go at it again :)
 
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There are a few tank repair products out there. I've used a JB Weld fuel tank repair. I ran a drill into the side of a gas tank (metal) years ago, and that has held up for 10 years now. They make a metal and plastic tank repair kit, so know which one you're buying if you go that route.

If you want to go a step further you can pull the tank, clean it out and slouch around a sealer like Redkote or POR tank sealer. I've used both in metal tanks, and they work well, but it's probably overkill for a plastic tank after you've done an external repair.
 
There are a few tank repair products out there. I've used a JB Weld fuel tank repair. I ran a drill into the side of a gas tank (metal) years ago, and that has held up for 10 years now. They make a metal and plastic tank repair kit, so know which one you're buying if you go that route.

If you want to go a step further you can pull the tank, clean it out and slouch around a sealer like Redkote or POR tank sealer. I've used both in metal tanks, and they work well, but it's probably overkill for a plastic tank after you've done an external repair.

JB weld is another good one. I have used Redkote and POR in motorcycle tanks. I could also just drive around with a CEL on. I have been doing that for years. I laughed last night when I test drove it. I made it all the way to the endo of my driveway without a CEL. Today I made it all the way to work with no CEL. That may be the longest I have driven without a code in a while :)
 
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I could also just drive around with a CEL on. I have been doing that for years.

I wouldn't play with potential fuel tank leaks. Not only do you have to worry about things coming in, like water, but you more so be concerned about things coming out, like fuel in the event of a rollover. I don't think death via gas fire is a chance I'm willing to take.
 
I wouldn't play with potential fuel tank leaks. Not only do you have to worry about things coming in, like water, but you more so be concerned about things coming out, like fuel in the event of a rollover. I don't think death via gas fire is a chance I'm willing to take.

I assume this is in reference to bypassing my fuel tank. I agree, I was just curious. Truth be told, I am probably going to go out in a gas fire, spectacular motorcycle crash or disappear fishing offshore some day. None of which I look forward to, but I am going to keep doing it.
 
like fuel in the event of a rollover. I don't think death via gas fire is a chance I'm willing to take.
Don't wear your seatbelt and that won't be a possibility. 🤫
WRECKED JEEP (2017_11_20 00_38_12 UTC).jpg
 
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A cousin of mine died when he was 10 because a tractor he was riding on rolled over on top of him and spilled diesel fuel on him.

Very sad. What was the actual cause of death, the rollover, or was there a fire?
 
Novak Conversions Jeep Wrangler TJ engine mounts