6.2L Stalling Off-Camber? Nose Down?

[Lizard Dog]

My understanding is that diesels don't, or are maybe less likely to stall off-camber.

I went wheeling the M1009 this afternoon and was coming down a very steep grade with large holes and rocks. I'm running stock 10-bolts and 31s so I was taking it very slow, just creeping down, but it was steep and crooked so I spent a fair amount of time on three wheels. Thing is, the truck kept stalling. It would start right back up again, but still inconvenient and disconcerting in that moment.

I have never encountered this before. I did some searching but couldn't find related threads. Do you guys suspect an issue I should look into? Any insight is greatly appreciated!

 

[tinygpw]

That should not cause a fuel problem. known them run "keeled over" untill we pulled/pushed them up again. Check the fuel pickup, and of course the fuel level in the tank. (dmetalmiki using nephews log in).

 

[Lizard Dog]

Thanks for the reply dmetalmiki. The fuel pump is 9k miles old and I have had no other reason to think it's faulty so far. I had a nearly full tank of fuel. :/

Could the flexing be opening an air leak somewhere?

Once off that particular hill, it didn't stall again. That was definitely the most extreme grade we encountered tho.

 

[dmetalmiki]

fuel fault.

Thanks for the reply dmetalmiki. The fuel pump is 9k miles old and I have had no other reason to think it's faulty so far. I had a nearly full tank of fuel. :/

Could the flexing be opening an air leak somewhere?

Once off that particular hill, it didn't stall again. That was definitely the most extreme grade we encountered tho.

That could be a cause, and might be difficult to trace, especially if it runs well at all other times.

 

[tourus]

also if the fuel tank is not factory it may not have and baffles in it .. I had a truck that with any thing less than 3/4 tank it would stall and any kind of incline. but yes start right back up . when I did have to replace the tank(due to hole) found that there was no "bowl to hold fuel " .. ??? maybe????

 

[Lizard Dog]

also if the fuel tank is not factory it may not have and baffles in it .. I had a truck that with any thing less than 3/4 tank it would stall and any kind of incline. but yes start right back up . when I did have to replace the tank(due to hole) found that there was no "bowl to hold fuel " .. ??? maybe????

Interesting... I don't know anything about the history of the tank so I suppose that's a possibility! What is the "bowl" you're referring to?

 

[rsh4364]

As far as I can tell there are no baffles in fact.1009 tank,and also no deep spot in tank for fuel pick up.I may be wrong .But Im in the middle of replacing rusty orig.tank with a 31 gal.new tank,neither one has baffles or a deep sump pickup for sending unit.

 

[jpg]

The CUCV fuel tank has no significant sump. It may have baffles, but they only slow the rate at which fuel moves in a tank. They can't keep fuel from flowing downhill.

Aerobatic aircraft fuel tanks use a "flop tube", a flexible fuel pickup with a weighted tip. When all the fuel goes to one part of the tank, due to gravity or G forces, that weight brings the fuel pickup tube to the same place. That's why they can fly along inverted, or at any crazy angle they choose, and the fuel pickup stays in the fuel.

If extreme incline driving is a big part of your life, and the stock fuel pick-up sucks air often enough to annoy you, you might consider installing a flop tube. It would take some thought. You don't want it tangling with the fuel level sensor, or tying itself in a knot.

Or you can install one of these fuel pickups at each end of your tank, and plumb them to your existing pickup tube. These pickups suck fuel, but they don't suck air. With one at each end of your tank, one or the other will always be in the fuel, and if one is in the air it will close, so you don't suck air. For our long, narrow tanks, I think this works better than a long flop tube that might get tangled.

Or, you could just keep your tank mostly full when playing on the steep parts.

My M1010's fuel gauge reading changes dramatically when the vehicle encounters an incline. If the fuel is moving out from under the fuel gauge sender, it's also moving away from the fuel pickup sock. I thought about what would happen if the incline were steep enough and the tank empty enough that the fuel pickup sucked air. I came up with the ideas above. For me, I figure I just need to keep the tank mostly full when playing on the steep parts. If it becomes an issue, I'd go with the pickup at each end of the tank. This hasn't been enough of an annoyance for me to motivate me to mod my fuel pickup.

 

[gringeltaube]

OP says it started right back up again, (every time) after stalling. I don't see how a 6.2L can do that and run right and smooth immediately after, if the cause was air sucked-in anywhere down the fuel supply line? It usually takes a lot of cranking until everything was primed again.


G.

 

[dependable]

Aerobatic aircraft fuel tanks use a "flop tube", a flexible fuel pickup with a weighted tip. When all the fuel goes to one part of the tank, due to gravity or G forces, that weight brings the fuel pickup tube to the same place. That's why they can fly along inverted, or at any crazy angle they choose, and the fuel pickup stays in the fuel.

Never thought about it much before, but the lowly string trimmer or chain saw uses similar device to operate at all angles.

 

[jpg]

OP says it started right back up again, (every time) after stalling. I don't see how a 6.2L can do that and run right and smooth immediately after, if the cause was air sucked-in anywhere down the fuel supply line? It usually takes a lot of cranking until everything was primed again.

I imagine he had a mixture of air and fuel. Imagine the fuel pickup near the edge of the fuel in a steeply inclined tank with fuel sloshing around vigorously as he negotiates a steep off-road trail. Sometimes it sucks air, sometimes fuel. So the fuel lines would have a mixture of fuel and air. When the truck stalls, the violent movement stops, and the fuel settles down. At that point, you will either suck all air and you're screwed, or all fuel and you're good to go. In that circumstance, one would be wise to "coast" downhill to as level a spot as is both safe and possible, and then start your engine there. That maximizes the chance that your fuel pickup is submerged.

It's all guesswork, of course.

 

[gringeltaube]

It really doesn't matter how air got into the IP. What I'm trying to say is once it got enough of it and the IP actually "pumped air" into the lines you are done for a while. There is no way that engine could just be restarted immediately after it stalled, and continue running - which is what the OP is describing.

Must be something else with the fuel shut-off, either electrical or mechanical.

 

[hatzie]

If the lift pump coasts for long enough to almost re-prime the system... the already warm engine would restart with only slightly more than normal effort because there's fuel in the filter again. Slight and short rough running might be ignored.

 

[Lizard Dog]

It really doesn't matter how air got into the IP. What I'm trying to say is once it got enough of it and the IP actually "pumped air" into the lines you are done for a while. There is no way that engine could just be restarted immediately after it stalled, and continue running - which is what the OP is describing.

This is true, I just had to kiss the starter and it would start back up, like a normal, warm engine. No feeling of having to re-prime.

Thanks for the great responses here guys, I'm glad I'm not the only one that was puzzled.

 

[Lizard Dog]

Must be something else with the fuel shut-off, either electrical or mechanical.

I'm not familiar with the fuel shut-off. What/where is that?

 

[cucvrus]

Top of the injection pump. Electrical built into the injection pump cover. That is what shuts off the engine. Heavy red wire. I doubt if that is the problem. Could be a dirty fuel filter or a return line that is restricted or getting pulled or cinched.

 

[Lizard Dog]

Could be a dirty fuel filter or a return line that is restricted or getting pulled or cinched.

Thanks, good call. I'll start with the fuel filter; I did the spin-on filter mod about 8k miles ago and haven't changed the filter since.

 

[WhiskeyDelta]

Was this a fix?
Sorry to jump in late but I'm having the same issues. Maybe even worse. I can't go up much of an incline at all or have it full throttle for too long before it "starves it's self". Well that's what I think. I just got the truck and have not pulled anything apart.

 

[dependable]

Change your fuel filter first, probably needs it anyway, and it may help your problem.

 

[cucvrus]

Low fuel level in the fuel tank itself will also do this. And the fuel pick up sock is dirty and not getting sufficient fuel supply to sustain a very short period of time being un-submerged in the fuel. That is my guess from afar. Have you ever changed the lift pump? Have you ever looked inside an aged lift pump. Not very nice inside. They will run a long time on a failing lift pump with out you even noticing it. Usually it just up and fails. If you have not changed it and you don't know when it was changed. Good time to change it and service the in tank fuel sock. Huge improvement. Good Luck I hope you have the repairs made for the April Rausch Creek Off Road Adventure/Jamboree.