uhho, he's back... fuel supply problem

[redbeard]

Yup, I still have the truck, No troubles after the carb rebuild and T-case.. ok full tuneup helped, plugs, wires, filters, fluids, ignition coil and fuel pump with inline 'clear' filter.

Yesterday, it quit running. Dry fuel filter. ok, gas problem, duh. Yes it had gas, 19 gal. I put 20.5 gal in there about 20 miles ago. When I put gas in it 2 wks ago there was a whoosh of air when I took the cap off. Hmm... not normal. After putting 20.5 gal in the 20 gal tank, I thought, wow, maybe I really was literally running on fumesl Vacuum from the filter sucking every thing out. Tried spare fuel filter, same thing.

Called my step-son about coming up today. He did. good kid.After messing with it for awhile, I went and bought new mechanical fuel pump. We blew the line out to the tank and heard lots of bubbles. After the pump, was better but not enuf to keep it running. Gas was kinda spurting out not good flow at all. When we blew through the 2 pumps, the old one passed air but the new one had no flow. Hole in internal diaphragm? Tomorrow I take the pump back toAuto Zone, and go to NAPA for the only one they have in stock... Electric pump time? probably? Wait for IRS refund in 2-3weeks for that. OH, if I go electric, is there anything else that I would need besdie the pump and 12 V source that is off when ignition is off?

We dropped the tank last fall and it did not have any crap in the bottom,It's plastic. Metal parts from float, sending unit or anything else metal was not rusty. Some dirt in filter, not much and I could blow threw it easily.

A friend stopped by when he saw the truck on the side of the road infront of our h ouse. He mentioned it could be the cam lobe or whatever it is called could be worn and not working the pump lever correctly. Is that possible? Ok, anything is possible...Is it something that is a common problem on the 318ci engines?

I think that covers it. Oh, last year I was inquiring about tires. I put the Dynasty mud terrain on and really like them. It's a bit wobbly over 60mph...but I am not using it for long trips anyway. 6 miles around trip and 3 or 4 times every 2 weeks or so. Can't even tell it's carrying 350 gal of water. Empty or full, runs the same. Someday, I will rebuild the engine and wiring so I can use it on trips. 4 wheeler in back and I am all set for hunting. If it had a cap I could sleep in the bed.

Thanks for any answers...

Myles

[Ron in Indiana]

Just a thought but when you said there was a whoosh of air when you removed your cap it may be that your cap isn't venting? You shouldn't have a vacuum in the tank with it sucking air like that. Take off the cap and try it, simple and easy with one more thing to eliminate for a diagnosis. The fuel pump cam could be worn but unless it's a really high mileage engine it's doubtfull in my opinion. You did get the pump arm under the cam when you installed the pump? Just trying all the options. The only electric pump I've worked with is the AirDog I installed on my '01 Cummins and it works great.

[Paul in MN]

Another idea

I have had some fuel supply problems on my W250/360 due to rust cracked steel fuel lines running along the frame where mud and stuff sits on the fuel line and against the frame rail. Also the rubber tubing at the top of the fuel tank going to the steel lines. The rubber has formed cracks from age and allows air to be sucked in with the gas.

I'd sure try the gas cap first, but then inspect the fuel lines very carefully.

Best of Luck!

Paul in MN

[redbeard]

fuel problems

I haven't gotten very far, couple more inches of snow in the last day and a half.

The fuel cap is new. I lost the other one a couple months ago and replaced it. I don't know if the new one is vented or not...Should I see a hole on the outside of the cap?

the tank was removed this fall. I can only hope that my step-son would have noticed bad fuel hose from the top of the tank. Inspection of fuel lines will be difficult unless the 50 deg. days of last week come back. I'd have to get underneath with a hose to wash the frame clean. Maybe a wire brush to expose the lines... the lengths of fuel hose under the hood are new.

Also mentioned was the lever of the fuel pump under the lobe or not...how do you know if it is or not? Note on the lever. the rub spot on the lever of both pumps are different. The old one shows a single rub mark it off to one side and the new one shows a double 'line' run mark pretty well centered.the old one is not any deeper than the new one. I did replace it a year or 2 ago.

If the internal cam is worn, that would explain the new pump not working. Bad new pump also possible...
Myles

[pieter]

Did this problem start around the time you got the new gas cap?
Easiest way to determine this is to just leave the gas cap off and run it on a trip and see if it dies. Then put it back on and run the same trip and see if it dies.

The whoosh when you remove the cap means the tank is not venting and creating a vacuum. Mechanical pump won't be able to compete against the vacuum.

Pieter

[OLD DODGE]

Check the gas cap as Pieter suggested but also here is some extra info.

The small block chrysler has an eccentric that bolts on to the front of the camshaft. If you have the pump off of the engine you may be able to peek inside to see if its intact or damaged. You may have to use a flashlight and a mirror. The eccentric is pictured below.

Also if the fuel pump is off you can get your finger in the timing chain cover hole and feel the tension on the chain. If its loose, time to replace it.

[redbeard]

going with electric pump.

I decided to go with an electric fuel pump and see what happens. It has like 5-9 psi rating. They had a smaller one for 2 bbl carbs, but I got the larger of the 2 incase I do switch to a 4bbl some day. AND the larger one was cheaper. 48 vs 85 or something. go figure. I also bought a vented cap to be sure.

Tomorrow afternoon I plan to install the pump. Now, I've always heard and the instructions for the new e-pump say to mount as close to the tank as possible. I have the plastic tank that sits on the drivers side and sits longwise in the frame. I can (probably) mount the pump on the passenger side as this seems to be the best place to easily access the steel line to cut and install pump. I have 16g wire that I can run from the engine compartment to the pump. Is this a heavy enough wire? I know it should come off a switched power source like maybe the wipers.

Of course, the easy choice is to mount it on the inside of the right fender or passenger side of firewall. Where ever the fuel line is easily accessed without running 4 feet of fuel hose to and from the pump. Any ideas or suggestions appreciated.

Local opinion from a couple ASE mechanics is the lobe on the timing chain broke. They said to try and see if it's there or feel it and see if it moves or is stationary. They said it's not always the piece itself but what holds it in place that breaks. I am going to try looking or sticking a screwdriver in there and see what I can see/feel.The pump is out so it wouldn't hurt to look.

In answer to a couple other posts, I replaced the fuel cap months ago. No trouble with vacuum until the fill up 2 weeks ago. Inspection of fuel lines show no obvious problems, signs of leaks, stains, etc. Of couse the question of vaccuum is still there. If the pump wasn't getting enough movement to pump gas, why would it cause a vacuum? It's not like the fuel source is above the liquid or close to it even.

Well to be continued...

anyone need 2 16.5 stock wheels? just thought I'd ask.

Myles

[mmwb]

I don't remember, but is there a vent tube on that unit?

[redbeard]

vent tube

Vent tube? I have no idea. I am trying to avoid removing the tanks as it's essentially full of gas. I do have 2 floor jacks so usinga 2x6 on the jacks, it shouldn't be too hard to get it down. hopefully, it would be down enough to see. With a vented cap, does it need vent tube?

If it has one, does the vent tube show when the tank is in place?

They are calling for snow again...Hopefully I'll have enough sun to stay warm on the ground. It's clouding up already.

Myles

[redbeard]

last question I hope...

I won't bury the question in a lot of other stuff. I bought an electric fuel pump and I need advice on the best place to put it.
Do I have toinstall the pump near the fuel tank which would be under the truck? Can I install it in the engine compartment? Firewall location would be closest to the tank. Can any 12v circuit that is activated by the ignition switch be used?

Thanks.
Myles

[mmwb]

I think the strength in the electric pump is in pushing, not pulling. It may have enough power to pull from the engine compartment, but will have to work harder to do so. Ie, shorter life of the pump. Mount it back by the tank. Run the line off of a fused relay from the ignition circuit. Use a heavy enough wire, and protect it from rubbing where you run it.

[MoparNorm]

That is correct. Fuel Pumps work better pushing, the closer to the tank, the better.

[redbeard]

fuel pump location

Thanks. It's the answer I was expecting.

Any suggestions for which circuit to use?

If I take the power off the firewall connections into cab, which wire circuit should I connect to?

thanks

myles

[MoparNorm]

It needs to be a keyed hot wire, to a relay and then the pump. If the engine dies, the pump should no longer be "hot". You do not want the pump running when the engine is not.

[greg rider]

It needs to be a keyed hot wire, to a relay and then the pump. If the engine dies, the pump should no longer be "hot". You do not want the pump running when the engine is not.

New vehicles shut off the fuel pump if the engine dies. This is to prevent the pump from feeding a fire in the event of a crash. Do not wire to an ignition hot as it could stay on in a crash. Best bet is go to a bone yard and get a crash switch from a Ford car. The switch is almost always in the trunk on the side somewhere. It will be marked with a warning sticker. Use at least 14g wire and a fuse or breaker. Remember when you mount things inside the frame rails that the driveshaft thinggy likes to throw mud, water, grease, and other goodies so try to protect it (the pump & wires) from damage.