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1st Gen. Ram - All TopicsDiscussion for all Dodge Rams prior to 1994. This includes engine, drivetrain and non-drivetrain discussions. Anything prior to 1994 should go in here.
Driving along on a highway, flat as a pancake, and I have this mysterious "running out of fuel" episode again. The last few times I had this, it was ~18* F, and I was cruising with my plow in the front of the truck. Today, it's ~ 50*F and it happened again, no plow, no load, flat road, highway cruising speed. I ran out of fuel, with a half full tank (13 gallons).
So I get towed off the Garden State Cash Cow, back home, and $250 out of my pocket less. Pulled the brand new Fuel filter, it's empty. Fill with fuel, crack the bleeders, and it purrs like a kitten. Filled the truck and it took exactly 17 gallons.
Here's my peanut brain theory:
Air in system
How's that ? Pretty good eh ?
Next... Why air in the system ? Well, it could be one of the lines that lead from tank to engine. Funny part is, that truck runs fine now, so why isn't it dumping fuel all over the ground with a full tank ?
Need to pressurize tank and see if we get any squirting.
Next thought: Bad pickup in tank. Good possibility that squiggly hose in the tank is cracked. I'm not emptying a 30 gallon tank, so when it gets low enough, I'll drop the tank and look in there. Parts aren't available anymore, so I guess if it's that (which I don't know yet) I guess I'll have to figure something out.
I'm tired of sitting on the side of the highway, so I'll be keeping a container of fuel in the truck, my hand dandy fuel filter wrench, and a 17mm wrench so that if / when this happens again, and I'm not splattered all over some highway somewhere, I can get it back up and running in a few minutes.
Mine has been a hard start a couple of times when the fuel gets down to 1/2 tank. I have a piston pump so I think it's good. I have tried the air pressure in the tank trick but I didn't see any leaks. So far I just keep it above 1/2 tank. It's down to about there now so I'll see if it does it again.
T-man we have talked about this at length over the phone last time it happened, so you have gotten my advise on this subject.
The fuel is not dumping on the ground as there is no leak with out major pressure...like when the LP that is sucking at 6- 7 PSI or so you get from your diaphragm LP. It is finding the weak link in your system and sucking that air as it is easier than pulling fuel up and out of your tank.
Pressurize the tank with a PSI or two and look for a moist spot to form on any connection from the tank to the LP.
When was the last time you changed out the O-ring seal on your fuel heater [I am guessing you have one] under the fuel filter?
you might be onto summin, dere homey. Can't say I ever have. I think I have a new seal in a box, but I'll have to check. I bought the 2nd gen heater a couple years back, but never installed it.
Good idea. Once we get a nice stretch of days, I'll do a pressure test and see what's happening. Unfortunately I just coated the under side of the truck, so unless it's obvious... I'm kind of screwed
Sounds like you have all the possibilities figured out already.. My guess would be either a leak in that squiggly line in the tank, or a lift pump that gets flaky after it's been running for a bit. Hope you get it solved without too much more trouble.
When was the last time you changed out the O-ring seal on your fuel heater [I am guessing you have one] under the fuel filter?
Do you have a fuel pressure gauge on the truck? Its one of those things that you rarely need, but then is super useful to have when you do need it . . . and is cheaper than getting towed.
It is something of a pain that you can't siphon out the tank without removing the check-valve from the filler tube . . . If I recall correctly, I had trouble with the pick up screen being crudded up, and the float assembly being jammed up with rust, as well as a stiffened coiled hose, but it has been a while, and I didn't take notes.
You could always go for the "live-tap" sump install if you are feeling frisky!
If you are 100% positive the pump is good, that leaves only 2 possibilities. Booth are between the pump and the tank.
#1. A leak between the bottom of the pick up tube and the pump which will allow air to get sucked in.
#2. Your tank is not venting allowing a vacuum in the tank that will prevent the pump from drawing fuel.
In your description #2 makes sense when you say it happens with lower fuel levels. Less fuel weight to overcome the vacuum.
Do you have a fuel pressure gauge on the truck? Its one of those things that you rarely need, but then is super useful to have when you do need it . . . and is cheaper than getting towed.
It is something of a pain that you can't siphon out the tank without removing the check-valve from the filler tube . . . If I recall correctly, I had trouble with the pick up screen being crudded up, and the float assembly being jammed up with rust, as well as a stiffened coiled hose, but it has been a while, and I didn't take notes.
You could always go for the "live-tap" sump install if you are feeling frisky!
Yes, and I read it frequently, as it gives me indications on fuel pressure at the pump. Average on a new fuel filter is 6 to 7 psi. It is still that after being towed home, and the 15 minutes of getting it running again.
Fuel tank was down 2 years ago . nothing inside but clean fuel . no algae , no debris, nada.
Whatever the actual cause is it's obviously a temporary issue, that subsequently fixes itself. Each time this has occurred, the truck fires back up, after manually filling the fuel filter and bleeding. I dive it after, usually to the filling station, but if the pickup tube was broken off, for example, I should, in theory, run out of fuel again, almost immediately. It doesn't. It goes on for miles after restarting.
it's as if a petcock gets turned off, truck dies, it magically gets turned immediately back on, and restarts.
Maybe I should gut one of the fss units I have, get the pull cable lever working, and run it down to nothing In the tank.
Or run a separate direct power switch to the fss, outside the trucks wiring harness, eliminating the possibility of a intermittent electric failure to the fs, as fss as well
One way or another, I'm sure you guys will figure it out for me
Hey T, I have to apologize, I had trouble with my reply about the heater gasket, and somehow deleted the important part, which was that I don't believe the gasket can be causing the problem, as a leak between the lift pump and the injection pump doesn't suck air, unless it is accompanied by a blockage between the leak and the lift pump . . .
To be 100% clear, when you have this problem, fuel gets sucked out of the filter, so the filter is not full of fuel when removed?
At what point in the line are you reading the fuel pressure? If you are at the filter outlet banjo (in place of the stock bleed screw), I don't see how you could show pressure on the gauge and suck the filter dry. If it is on the inlet side of the filter, then I would think there must be a clog between wherever you are reading the pressure and the filter.
I don't see how the FSS can be causing the fuel filter to be filled with air, not matter what may be wrong with it or other parts of the system.
Yes. The fuel filter is empty when I break down. I fill it up, crank it over, with the injectors loose, it stumbles, I close the injector lines, and it starts back up. Runs like nothing ever happened.
Unfortunately, as I'm realizing it's breaking down, I'm usually on a highway doing 60mph, with cars all around, desperately looking for an "out" to safely park the dead truck, minimal power steering. the minute I get it cranking, it shows fuel pressure.
The Fuel pressure sender is located above the filter where the bleeder screw was, as that was in the instructions, when I bought the kit.
The only reason I questioned the fss is in my mind, each time I'm driving and the pedal disappears, and I realize I'm in a pickle again, I'm wondering if the engine, being at near 2000 rpm, could suck the filter dry, if indeed there was an electrical failure (intermittent) to the fss. Its just an alternative theory of why this is such a weird....once or twice a year occurrence.
Trying to grasp, in my brain, why its a rare , self healing occurrence. If it was the pickup tube in the tank, I wouldn't be able to continue driving for miles after each occurrence, as the fuel doesn't raise up above the supposed break in the line.
The commonalities are as follows:
On flat highway
Doing 50+ mph
Minding own business, just relaxing, when pedal response disappears
Engine dies,
Panic to find safe pull off
Pull filter off its empty
Fill filter, bleed injectors
Drive home for miles.
The self healing aspect of this irritates me. This is why I was exploring the electrical pathway, as I've had plenty of electrical issues that mimicked the self healing principal.
I think I'm going to install a separate, fused switch to the fss that guarantees its not losing power.
Am I incorrect in thinking the fss shutoff, at 50mph, would cause the fuel filter to vacuum suck dry ? Is this a possibility, or am I heading down the wrong path?
I will still try the pressurize tank process, once I get a dry day allowing so. I want to put a gauge and Schrader valve, so I can walk away for a few, to see if the couple pounds of air goes away, if I don't get an immediate leak, like Edwin experience went.
I get what a cluster it is to try to diagnose something when you're in traffic . . . especially in a place where drivers think all vehicles stop like a ferrari, and a car length of following distance is an invitation to change lanes . . . That said:
Am I incorrect in thinking the fss shutoff, at 50mph, would cause the fuel filter to vacuum suck dry ? Is this a possibility, or am I heading down the wrong path?
The FSS can not cause the filter to get sucked dry.
The Fuel pressure sender is located above the filter where the bleeder screw was
Given this, I expect that the fuel pressure registers 0 psi when the truck is dying. Is this correct?
If it was the pickup tube in the tank, I wouldn't be able to continue driving for miles after each occurrence, as the fuel doesn't raise up above the supposed break in the line.
Suction leaks can be very intermittent in appearance. Further, the pickup assembly is designed to create a "reserve" in the strainer basket area, and the float pickup assembly can be bouncing around up and down to an extent.
I would inspect for leaks (to map any damp spots, etc. prior to testing) throw rags around a blower nozzle with the regulator set below ten psi, pressurize the tank for 30 seconds or so, and look for any new wet areas. In my experience, they show up right away. If you don't see anything, you will need to remove the pickup assembly and inspect/test it.
I have the fuel tank cap with the quick connect in it. I'm thinking it would be a good idea to use a schrader valve instead so the tank could be pressurized and checked with a tire pressure gauge. Then walk away for 30 minutes and come back and check the pressure. If the pressure drops then you have a leak. Would the IP allow fuel to bypass and leak into a cylinder etc... and defeat this idea?
As I said before I have this exact problem except it hasn't failed on the street. It usually fails to start when the tank gets down to half on the gauge.
I have the fuel tank cap with the quick connect in it. I'm thinking it would be a good idea to use a schrader valve instead so the tank could be pressurized and checked with a tire pressure gauge. Then walk away for 30 minutes and come back and check the pressure. If the pressure drops then you have a leak. Would the IP allow fuel to bypass and leak into a cylinder etc... and defeat this idea?
As I said before I have this exact problem except it hasn't failed on the street. It usually fails to start when the tank gets down to half on the gauge.
Edwin
Having it loose pressure doesn't prove much as the rubber fuel filler neck seal on the tank is only so strong and will be a leak point.
I would look for leaks, or moist spots of fuel leaking from lines or connections more.
NJT, is the line from the tank the stock hard plastic or has it been replaced with a rubber hose? My theory being that if it is a rubber line it could be deteriorating inside like a bad brake line and it has a flap that occasionally flips up shutting off the fuel.
12-14-2018, 02:17 PM
