[russ300h]

This Jeep is driving me nuts. I inherited it from a neighbor in a deal we made. I don't know what to do with it. I was thinking about keeping it, but..... The problem - Since I have been driving it the fuel gauge has been off. According to what I find the fuel tank is 25 gallons I have been filling it up at an indicated quarter of a tank. It only takes 13 gallons. Yesterday the gauge went down to the top of the red section and I wasn't concerned because it "should" have plenty left. Don't you know, it ran out of gas!! I call a friend, get a fuel container and bought some gas. I added about a gallon, just to get me to the nearest station about half a mile away. It starts up, runs like crap and dies. I tried this three or four times with the same result. I had to call a wrecker and have it brought to a garage. Close to sixty years of driving, I have never had a problem like this. Then again, I've never run out of gas on as new a vehicle. Does anyone know why the Jeep acted in that fashion in the way it did and what a remedy might be? I want to have some idea when I go to pick it up. Any input appreciated!! This forum is the best for helping with problems like this TY!!!!

 

[AllanC]

. . . The problem - Since I have been driving it the fuel gauge has been off. According to what I find the fuel tank is 25 gallons I have been filling it up at an indicated quarter of a tank. It only takes 13 gallons. Yesterday the gauge went down to the top of the red section and I wasn't concerned because it "should" have plenty left. Don't you know, it ran out of gas!! . . .

On Jan 06, 2021 you posted a question about this vehicle. Did you resolve the issue with the P0700 code and the intermittent stalling and no start?

I have checked several sources of information about fuel tank capacity on a 2006 Jeep Commander and all indicate 20.5 gallon capacity. So you do not have as much fuel as you think. If there is an owner's manual in the vehicle you can cross check fuel tank capacity.

I am thinking the fuel level sending unit is failing and sending erroneous resistance readings to the instrument cluster. It is possible that you have a wiring problem but most likely there is a problem with the sending unit. The unit is attached to the side of the fuel pump module so gaining access requires dropping the fuel tank.

 

[russ300h]

On Jan 06, 2021 you posted a question about this vehicle. Did you resolve the issue with the P0700 code and the intermittent stalling and no start?

I have checked several sources of information about fuel tank capacity on a 2006 Jeep Commander and all indicate 20.5 gallon capacity. So you do not have as much fuel as you think. If there is an owner's manual in the vehicle you can cross check fuel tank capacity.

I am thinking the fuel level sending unit is failing and sending erroneous resistance readings to the instrument cluster. It is possible that you have a wiring problem but most likely there is a problem with the sending unit. The unit is attached to the side of the fuel pump module so gaining access requires dropping the fuel tank.

Hi Allan: Thanks again for your input! The Jeep only showed the P0700 code that one time and it never returned. I kept starting it while it was parked for about three days (about a dozen times) and never had the problem again. Eventually I dared to take it out and drive it. with no further problems.

My mid 70 year old brain could have read 20.5 and think it was 25! The only thing good about getting old is it beats the alternative!! Even so, when the indicator was on the beginning of the scale where the red section ended I could only add 13.7 or so gallons .That should still give me six or so gallons remaining ! What bothers me this time is after adding new fuel, why does it run so rough and just quit? Over almost sixty years, I have run out of fuel a few times. All I have ever had to do is add gas and I would be on my way. This starts, runs like it is on four cylinders for about ten seconds and then dies. Back to my Durango R/T I guess! Still has a computer, but never a problem with it!! You guys here are terrific Thank YOU!!!

 

[AllanC]

. . .Even so, when the indicator was on the beginning of the scale where the red section ended I could only add 13.7 or so gallons .That should still give me six or so gallons remaining ! . . . .

Thirteen point seven ( 13.7 ) divided into 20.5 is about 0.67 or 2/3. When driving the vehicle does the fuel gauge suddenly dip to empty and then return to a believable reading on the gauge? With a full fuel tank, does the gauge pointer indicate full?

. . . What bothers me this time is after adding new fuel, why does it run so rough and just quit? Over almost sixty years, I have run out of fuel a few times. All I have ever had to do is add gas and I would be on my way. This starts, runs like it is on four cylinders for about ten seconds and then dies. . . .

When does this erratic running and then stalling occur? After running the tank empty, you add a fuel gallons, engine starts but runs erratic and then stalls? Or does the erratic running / stalling occur after stopping to add fuel at a retail station (tank not empty), you restart and the erratic running occurs?

 

[russ300h]

Hi Allan: No, I have never seen it dip below the red portion on the gauge. When full, it pegs to the right and shows just beyond the full marker. I have always added fuel when it dropped to what I would call the warning segment. Whatever the capacity, I knew it was (should have been) above empty at 13.7 gallons. I was going to go to my usual station only a few miles away.. It started running rough and died in the parking lot of a CVS. Called a friend, got a can of gas and added about a gallon. Then attempting to start it, it runs rough and stalls This is the ONLY time it has showed these symptoms. I just (wrongly) figured that I had a little cushion when the indicator was at the top of the red (warning) section. As the old saying says: Go Figure!!!!! Thank You again I really appreciate the help I can get here. .

 

[AllanC]

. . . No, I have never seen it dip below the red portion on the gauge. When full, it pegs to the right and shows just beyond the full marker. I have always added fuel when it dropped to what I would call the warning segment. Whatever the capacity, I knew it was (should have been) above empty at 13.7 gallons. I was going to go to my usual station only a few miles away.. It started running rough and died in the parking lot of a CVS. Called a friend, got a can of gas and added about a gallon. Then attempting to start it, it runs rough and stall . . . . .

There should be a low fuel indicator lamp symbol that illuminates when the fuel tank has about 2.225 gallons remaining. Have you seen that indicator turn on?

The fuel tank is a long and narrow configuration with the fuel pump module mounted in the center. With only 2.225 gallons remaining when the low fuel situation occurs, it is possible that city driving with stop and go and turning causes fuel to slosh and move away from the fuel pump pickup. If there was a moment when the electric pump lost its fuel prime and air entered the system, this would cause surging and a stall. See image. But the fuel pump module has a plastic well around the pump intake that tends to keep fuel located at the pump pickup for low fuel level conditions.



So you have an intermittent condition which causes stalling. It could be a mechanical problem of low fuel level and the fuel is moving away from the pump pickup and causing the pump to lose its prime. Or it could be an intermittent electrical problem with a poor connection to the ignition system or fuel delivery system.

The Jeep Commander uses a FCM / front control module but does not have a TIPM / totally integrated power module. So all the relays in the system are accessible in the fuse box and easily replaceable. Next time this happens try swapping the fuel pump relay and the starter relay in the fuse box. Test to see if the vehicle will restart easily.

To validate the low fuel / fuel pump losing its prime try this test. Allow fuel level to reach the low level as indicated on the gauge and low fuel lamp illuminates. Find and park on an inclined area with nose of vehicle substantially higher or lower than rear. Will the engine continue to idle or does it stall? If it stalls then you know a low fuel level condition that leads to the pump losing its prime is occurring.

These are some ideas to try. Intermittent stalling is difficult to diagnose and isolate.

I did some research and got lucky and found a download for the factory service manual for 2006 - 2010 Jeep Commander. This may be of some help to you. I used McAfee virus protection scanning software and did not find a virus in the file.

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