Weird Fuel Problem...

[Jax2A]

2002 3.7L Sport...

After finally fixing (I think) a overheating problem (replaced the fan relay, t-stat, hoses and radiator), I now have a strange problem.

After driving the Jeep a couple of days after the radiator replacement, I parked it on Sunday night with a half tank of gas. I rode my motorcycle Monday and Tuesday. Wednesday morning I went to the Libby, turned the key and it cranks & cranks but doesn't catch. Back off the key and the gas light comes on and the gauge is bottomed out.

So...

Anyone ever hear of a problem like this? It's on a gravel drive, no obvious signs of a leak. No obvious signs of tank damage.

Is there a spot low enough in the fuel lines that could leak and siphon out the tank?
Is it possible someone could siphon it that dry? (I wouldn't think so)

Last night I got home late and I only had about a quart of gas on hand to put in the tank and it wouldn't start on that (should it have?) and I didn't see it leak out.

Plan is to get more gas today and try again with a couple of gallons worth, but suggestions are welcomed...

Jack

 

[rockymountain]

Do you have any records on how many miles you've driven on said tank of gas? Maybe you have a bad sending unit.

 

[Jax2A]

80-100 miles... I keep my mileage/fill ups in an app call Gas Cubby on my phone religiously but I can't go look at my odometer right now.

 

[rockymountain]

If that is in fact true then the gas got out somehow. Have you got under it and looked for holes in the tank? I've heard of people drilling through the tank. They're just plastic. Now, if you have a skid plate then it would be different.

 

[tjkj2002]

Sounds like a bad guage or bad level sensor and you ran out of gas.

I know my gas gauge is wildly off,has been from day one(bought brand new) but does not matter as I never let if fall under 12 gallons(18.5 gallon tank).

 

[Jax2A]

No holes or cracks that I've been able to find yet. That's why I was wondering if a leak in the fuel line at a low point might continue to siphon off the tank after the engine shut off.

No skid plate either.

 

[rockymountain]

I'd also think you would smell gas if it was leaking that bad. If you had a half tank and came back to find it empty then around 10 gallons would have leaked out. That would smell. If you only got 100 miles out of the tank then that would be around 5 MPG. Something isn't adding up here.

 

[Jax2A]

Ran out of gas 100 miles after filing up? Right after backing in to my parking spot and shuting off the engine? Too coincidental and unlikely... plus it does scrape out better mileage than that, even though sometime it doesn't seem that way. Normally get about 18.3 mpg.

Sounds like a bad guage or bad level sensor and you ran out of gas.

I know my gas gauge is wildly off,has been from day one(bought brand new) but does not matter as I never let if fall under 12 gallons(18.5 gallon tank).

 

[tjkj2002]

No holes or cracks that I've been able to find yet. That's why I was wondering if a leak in the fuel line at a low point might continue to siphon off the tank after the engine shut off.

No skid plate either.

If you had a fuel line leak you would know,1st by smell,2nd by severe power loss,and 3rd would almost result in a fire if that bad.

You could have stuck open injectors leaking by but that much would mean your engine crankcase is full of gas.

 

[Jax2A]

I know, that's why I was thinking gas theivery... but is it possible someone could siphon it that dry? I wouldn't think so.

I'll know more once I pour a couple gallons in it tonight I guess but I thought the collective might have already experienced something like this.

I'd also think you would smell gas if it was leaking that bad. If you had a half tank and came back to find it empty then around 10 gallons would have leaked out. That would smell. If you only got 100 miles out of the tank then that would be around 5 MPG. Something isn't adding up here.

 

[Jax2A]

Agree with the smell and fire... and was running fine when parked.

If the injector stuck that would be a heck of a lot of gas to get in the block/crank case... don't think it would fit but I'll check the oil to make sure.

Plus with the injectors being higher than the tank, I wouldn't think it would continue to siphon out the gas.

If you had a fuel line leak you would know,1st by smell,2nd by severe power loss,and 3rd would almost result in a fire if that bad.

You could have stuck open injectors leaking by but that much would mean your engine crankcase is full of gas.

 

[Jax2A]

No update on the "leak" last night... was raining too hard to check, everything looked like it was leaking. Hopefully things will dry out for tonight.

Does anyone know if OBD will throw a code/check engine light if the fuel pump is dead? Would be nice to know for peace of mind even though I'll know if I get to pour gas in it tonight to check for leaks.

 

[Jax2A]

OK, more info...

I no longer believe the tank is empty even though it sounds like it when you thump on it. I put 4 gallons in it and no leaks or drips... I think I have a electrical or computer problem now:

Further investigation reveals front wipers don't work (but squirter does) and I'm guessing the gauges don't work because the fuel gauge should come up with the key on, and probably the fuel pump.

All other electrical devices seem to work including back lights on the cluster.

I disconnected the battery with no results... Confirmed the fuses and relays are good... So I guess my next step is to go rent a code reader to see if that tells me anything.

Anyone know of anything that would knock out the gauges, fuel pump and wipers even though everything was working fine before sitting for two days?

 

[rockymountain]

How's the battery?

 

[tjkj2002]

Check the fuel pressure,gauges are had at any auto parts stores for fairly cheap.The test port is on the passenger side fuel rail,kinda under the heater hoses/coolant tank on the 3.7.Just screw on,turn key to "Run" and check the pressure,should be about 58psi with KOEO(Key On Engine Off) +/- 2-3psi.

 

[Jax2A]

Battery is good.
Fuel pressure, check is next on the list but do need to get a gauge since I don't have one.
Tried all the key-on-off tricks to get the codes, but none worked.
The hold-tripmeter reset-key-on-off trick to check gauge cluster did work but gave no codes.
Ordered a OBD-II code reader last night (wifi to tie to my iPhone) off the internet but found out this morning that Advance Auto doesn't do readers through there tool loaner program but will read your codes at their store. Since it won't start to take it to them, I guess I'll get a gauge and test the fuel pressure and wait for my code reader to arrive.

 

[Jax2A]

Ok, bought a gauge and checked fuel pressure on the rail. Zilch.
So either fuel pump is dead or not getting power...

However since my fuel gauge and wipers aren't working either, I suspect the problem may not be limited to the fuel pump.

Guess I'm back to waiting for my code reader to arrive. Ordered a wifi unit so I can tie into vehicles through my iPhone. Hope it gets here soon.