Ethanol and Fuel Lines

I think the Ethanol issues have gotten to the CJ... Replaced the pump this weekend and it's still not pulling fuel from the tank. I'm considering changing all the lines; hard and rubber and POSSIBLY dropping the tank as well. Any other way to TS this would be appreciated!! Any recommendation on hardline resources?

 

Sorry to ask the obvious, but you've changed the filter? And your new filter passes fuel too (so wanted to say 'passes gas').

no reason I can think of to change hard lines unless you have rust in them.

can you get fuel from tank by siphoning (gack if you get it in your mouth, not heathy) or just draining it to a low spot from the fuel lines?

I'd try an electric first, just a few bucks from flaps, hook it near the tank, pump into a fuel can, then move it down the line to see if clogged...

Wonder if there is a screen on the tube in the tank that might be clogged? (May be a glob of varnish clogged it).

others may have other pre-drastic measures...

good luck.

 

Inline filter (x3) was changed before and after the carb rebuild. Had been running fine for two months and then this. Fairly certain the fuel pump (arm) eccentric is not worn inside the engine. That's how I know fuel is not reaching the carb... Fuel is not flowing thru the (clear) filter. I've heard of pressurizing the fuel line and blowing back toward the tank to try and clear any obstruction; but have never tried it. Interesting comment about the metal lines; maybe I'll just start with the rubber ones.

 

Cheapest source for hard line is Del City, AFAIK. http://www.delcity.net/store/Hydraulic-Steel-Brake-Line-Tubing/p_798744 Use your old lines as a pattern, and bend it up. I would try to use as little rubber hose as possible ...

Realize that if there are any leaks in the lines, the fuel pump will not pull fuel from the tank. It's like sucking on a drinking straw with a hole in it. A '71 CJ has a rear mounted tank, and there are short lengths of rubber hose between the hard lines and the tank pickup. On my '75, the return line connection was completely rotted, and let gas spill out the top of the tank. The only way to fix that is to drop the tank and replace the hoses.

I would test that you can pull gas from the tank with a Mity Vac. Connect to the fuel pump feed from the tank. It should take very little pumping to fill the Mity Vac bottle with gas.

 

Now we're talking! I don't have one of those but would certainly buy one to check this. What model would you recommend? I've thought about getting the unit HF advertises; just never had a real need...

 

Comments about the HF model seem positive - http://www.garagejournal.com/forum/showthread.php?t=72423

I bought mine years ago - looks like this is the modern equivalent - http://www.amazon.com/Mityvac-MV8000-Automotive-Test-Bleeding/dp/B00265M9SS - I know I paid less than that... but it must be a decade old.

 

Lacking the Mity Vac, you should be able to siphon to a jar on the floor from the tank line. Any leak or blockage should stop the siphon.

 

You could also rob a bulb off an outboard motor tank and use that to suck out gas from the tank...

 

"I've heard of pressurizing the fuel line and blowing back toward the tank to try and clear any obstruction; but have never tried it."

That would be the very first thing to do. The in-tank filter screen can get clogged with particles.

 

if you want a cheap and only tool required is a hose in the tank and pressurize the tank and instant siphon. better than sucking fumes and drinking gas

 

I went ahead and bought (ordered) the Mity Vac 8500 kit. Been wanting one for sometime now, so perfect opportunity. Since it permits pressure and suction it should work out for a variety of automotive and MC uses... My plan is to hook up to the "INLET" line to the fuel pump and see if there is any blockage by applying pressure toward the tank/ listen for leaks and then pull a vacuum on the same line. Not looking forward to (possibly) having to drop the tank... the four rear bolts for the skid plate look like they could be painful to get out.

 

The two rear corner bolts that hold the tank up are the more troublesome. Removal of the skid plate is straightforward. Unless the bolts are badly rusted, they should thread out of the rear crossmember. IIRC they are self-tapping and there is no nut to hold on the back side.

 

I had the same issue. Mine tank is under the seat though. Same symptoms. I finally traced it to the screen in the tank. I blew air and cleaned it but whatever was in the tank floated right back and my wife had to come rescue me. I had the tank cleaned at a shop and have had no more problems.

 

"Not looking forward to (possibly) having to drop the tank."

I blew back the line, then opened the tank drain to remove sediment. I also put a magnet in the tank which I cleaned frequently until it took out most of the rust particles.

No more problem.

 

So... Not an issue with the fuel tank and lines gumming up as I can tell. The Mity-Vac 8500 is the tool I used to check if there was any vacuum (indicating a blockage) on the line from the tank to the fuel pump inlet by disconnecting at the rubber line near the firewall. Within three pulls on the handle I had a solid stream of fuel and five pulls filled the catch jar. Performed that at least 10 times with same result. At that point there was no need to apply pressure thru that same line toward the tank.
Bottom line (I believe) is the old "cracked straw" syndrome... the clamp on the carb fuel filter inlet hose needed adjustment to prevent a slight leak that I (for what ever reason) didn't initially see. Once I got it to start the leak was visible on the underside of the hose. The loss of that vacuum to flow fuel to the carb is what prevented the engine from running.

OBTW... Not sure why I waited so long to get a Mity-Vac; it's very useful. Just performed my first (no assistant needed) brake system bleeding evolution. Worked flawless!

 

Yep when I first discovered mityvac tools I was like why didn't I get this thing sooner. One man brake bleeding, fluid removal, pressure and vacuum tests it's all awesome.

Just yesterday I received a mityvac tool for pressure testing cooling systems and caps. It was so quick and easy found 2 leaking hose clamps on my silverado and 1 leaking hose clamp on my 48 cj2a. $50 unit new and bought ebay used 1 time for $11.50 free shipping. Simply amazing

 

Chris how did you attach the vacuum hose to the bleeder nipple? Did you put the hose straight on the nipple or did you use the tapered bleed adapters like I did? That was the only way I could get the hose attached at the same time as my wrench.

 

Just a quick note, I put the sender in my 1960 DJ 3 with silicon sealer. It dissolved in the gas and formed a gob on the screen, the Jeep would run for a while and stop. I would hook a hose from a tire and blow backwards thru the fuel line and it would run for a while and the same thing. I finally took out the screen and put an in line filter in it, no silicon this time.

 

Good point... I used a tapered adapter at the end of the Mity-Vac clear tube and then lightly inserted it into the rubber fuel hose attached at the firewall. No issues with sealing at all.

FWIW... I too will be purchasing additional adapters for other uses; first one being the cooling system. I'm a believer!