Frustrated! Any suggestions?

Good Afternoon,

After some 4 wheeling the other weekend, I was driving the CJ home when the engine shut off on the highway.

Well, I should back up. While 4 wheeling I noticed a running gas leak coming from the back. Apparently the 30 year old hoses gave out around the Liquid Check Valve, but I managed to do a field repair (duct tape) and keep her running on the trail.

So, the engine shut off b/c the vacuum line going into the LCV snapped. Again, I managed to do another field repair and get her home.

I ordered another LCV from www.jwjeeps.com and replaced the broken part, along with all the hosing and clamps.

While doing the repairs, I also cleaned the jeep and replaced the fuel filter, which was one of those clear plastic ones, but it had mucho chunks floating in it. When the engine (AMC 304) was rebuilt, they took out the original factory fuel filter and replaced it with an inline.

O.K., so the repairs were done and I was back on the road. I had taken the jeep to work about and around various errands to test her out. No problems.

Then, as I was going across town to visit my brother and show the nephew the jeep (he thinks it's a jungle gym) the engine shut off again.

The fuel filter I installed was much smaller than the original, but still the same style, clear-plastic w/ the orange internal filter.

I barely got the jeep home and garaged it until I figured out what to do. The easiest thing was to replace the fuel filter again, which this time I installed a much larger FRAM inline metal canister. Again, the jeep fired right up and ran like a champ for a day or two.

Now, heading to work, the same darn problem happened again! Once I hit the high end of second geer (T-150) the engine shut off again!! I rolled into a neighborhood waited a moment and she fires right up. It should be noted that never during this time have I lost electricity.

So, here's my question. Could it be that the fuel filter is clogged again??? I think unlikely, but it's possible. The jeep was stored for many years before I picked it up.

Could it be also that it was a faulty LCV that I installed? Could there be another problem that I'm not considering? Any help is GREATLY appreciated!

Thank you!

 

Correction, it was www.jwjeep.com. Any suggestions is greatly appreciated!

 

I would bet your gas tank is full of rusty mud.
You need to take it off and look at whats going on in there.

Very common on rigs that spend some time just sitting around.

New filter will just do it again.
If you break the filter you will have a bigger problem.

A glass filter is nice because you can clean it but I'm pretty sure you have a bigger prob.

 

You were out wheeling with 30 year old gas hoses?

Oh, and I agree about the gas tank. Take it off and get it cleaned out. Radiator shops can do this quite well. It probably has 30 yrs of crud in it.

 

Haha!! No, no, most things have been upgraded or replaced. I just neglected the two hoses from the LCV to the tank, and one from the vacuum connection to the LCV. It only leaked on an extreme uphill. Honestly, and this sounds stupid, but I just didn't think about them.

O.K. So it sounds like I have a bunch of junk in the tank. I guess that is to be expected. Is it worth it to try and clean the tank? Is there any additives that can help clean it out w/out taking it off?

If I have to replace it, is the 21 gallon upgrade worth it? Does it fit in w/out too many modifications?

 

you will have to take it off. but on my fathers ford tractor he had the same thing happen. drained it and filled with distelled viniger and and then drained it 24 hours later and then rinsed. worked good on that tank.

 

Assuming......

Its your tank (probably).

just cleaning it out will not fix all the surface rust in there.

Take it to a shop and they will check it all out and they can boil it out.

Doing this halfway will mean doing it again.
Believe me I know.

If it is shot I would go bigger. But make sure it will fit first.
CJ's are infamous for not being stock.
like say wider springs may make for cleance issue's. ect.

Some here have had a hard time getting the tank out as well.

One Idea would be to stick some thing down the filler tube and pull it out and check for crud, rust ect. Or cut open the filter and see what you get just to make sure.

common symptom is it will idle but when revs go up, down the road it cloges up and starves for gas then will start back up and idle.

 

you prolly got crud clogging the fuel pickup and after it stalls the crud falls away. BUT! check to make sure there IS crud in the tank so your not going on a wild goose chase. Another thought is if you have the Carter yf carb I had the float needle seat back off and lower the float level to the point that on high load it would stall. But that was after a rebuild.

Just some ideas. Good luck!

 

I know the 21 gallon tank sits lower, there's extensions for using the stock skid plate. I personally wouldn't want to lose the clearance.

I had this same issue. All old rubber, main tank full of crap. Had to drop the tank and just replaced it with another steel one. With the sending unit kit, and fill tube it cost around $135 iirc. The new tank had to be shaved around the edges to fit in.

I ended up using my old fill tube. It has an overflow line that feeds to the tank, no replacement was furnished with the kit, and I wasn't sure I could make it seal tight on the new tube. Luckily my old fill tube seems to be in good shape.

My under seat tank was pretty good, just a little bit of gunk. I'm running some gas through it with 2 inline filters and plan on just swapping them out often until it starts to run clean. No way that would have worked with my old main tank, too much crud.

One goofy think I noticed is that the under seat tank has no seperate return, it uses the return to the main tank. So you can't run it on just the spare tank, and if you have both... w/ the spare tank on and the main tank full then there's no place for gas to return. I can't think of an easy solution to that one.

 

I would install a fuel filter before the fuel pump, to catch the crud from going thru the pump......maybe it is to late for that....
I'd install a new filter, then carry a new for a spare; easy to switch out on the road; this will also test the crud theory.
dropping the tank may be the ultimate cure for the problem.

 

all you really have to do is to remember to run the main tank first unitl it's very low; then switch tanks.
but as you drive, returned fuel from the front tank will gradually refill the rear tank; so you'll notice the front tank fuel gauge will drop rapidly; when the front tank runs low, simply switch back to the main.
This of course is assuming the front tank holds less fuel than the rear tank.
you'll still have to be careful of overflow
in the end, you will have filtered the fuel a couple of times

 

The gas tank theory makes alot of sense. I guess bringing the jeep back to life and driving her around allowed the gas in the tank to kick up all the old gunk in the tank. The symptoms described are exactly what is going on, and replacing the filter only solves the problem for a short while.

I checked with some radiator places. They said it's about $100 to have my tank cleaned. They warned me that it doesn't always work. They said sometimes they get the tanks out of the boiler that they use to clean them and it ends up causing more damage.

If that's the case, I would end up having to buy a new tank, which can be purchased for about $150.

The question now is, Steele or Plastic? I think I would stick with the 15 gallon to keep the clearance. They say the plastic ones are pretty tough, and all new cars have them, but I have a hard time believing the plastic would hold up in the Arizona backroads.

What would I ever do w/out this forum?

 

After dragging my '73 home from the middle of the pasture, getting it running, and spending days trying to get the gas clear, I put a new tank in (under $100). I couldn't believe the amount of crud and water in the old tank. No problems since.

 

http://www.thejeep.com/mtstanks/jeep.htm

Plastic tanks!


My blazer has a steel tank and plastic skid plate

 

i found some pretty cheap steele tanks @ http://www.xtremeterrain.com/p111.htm

 

i am going to go a different route here. I had this happen to me on my willys truck. it was unpredictable, and usually happened at higher RPMs. as soon as it shut off and i coasted to a stop it would fire right up and run fine. Until i got down the road a bit and it did it again. Turned out that the paper element inside my clear plastic filter was collapsing on itself. Yes, it was oriented correctly, but it was collapsing. It took me a while to catch it in the act and i finally only did after watching it while running it at higher rpm for a couple minutes in the driveway. sure enough it would slowly start to collapse and starve the engine. then as soon as the pump stopped pumping due to engine not running it would take about 15 seconds for the filter element to relax back into its natural state and it would flow fine again.

for me, i quit buying cheap clear filters. I bought the clear holley job with replaceable filters in it. i have them in both the M38 and the truck now so i can interchange spare parts if I need to.

Could be crud in the tank, but start with the simple stuff first and replace that filter with a good 10 dollar job.

seems to me the problem didn't really start until AFTER you replaced the old filter with the one on their now. I would start there. As the late Grandville King used to say, "refer to the last repair".
good luck

 

Rodger that!! I'll try the $10 filter first! I'll post when I have the results!

 

I agree, I have the 22 gal replacement tank, the extra range is nice, but I miss the clearance, I have scraped the rear tank several times while offroad.

Jay

 

Alright. I put one of those fancy-schmancy glass fuel filters on w/ the mesh filter that you can swap out. Then I took it for a ride around the neighborhood and tried to rev the engine as much as possible downshifting and accel. Sure enough, when the engine warmed up, she stalled once on a main street, fired right back up and continued to run home. I checked the filter after I was done running around and there are NO particles of any kind in it.

Is it possible the problem is with the replacement Liquid Check Valve that I installed? Any other ideas?

 

Could you by-pass the check valve and test drive the beast?