06 4.4i no fuel pressure
 

Died on the freeway on Sunday - sudden loss of power and engine stopped. Towed home. Cranks and tries to catch occasionally. Verified fuel pump running. Tested pressure at rail and got nothing. Pulled pressure gauge and pressed schrader valve needle and gas dribbled out.

Replaced fuel pump last August after identical symptoms.

https://xoutpost.com/bmw-sav-forums/...ple-hours.html

OBC test 6 shows 0.0 left, 27.0 right and 27.0 total.

Looking over the excellent post from Andrewwynn:
https://xoutpost.com/bmw-sav-forums/...stic-help.html

About to pull both tank covers and see if I have leaks in the siphon hoses. Anything else I should be looking for? I hope the Delphi pump I bough last year isn't failing already.

06 4.4i no fuel pressure
 

27 is Max reading on right tank so indications are an open or a short (whichever causes max).

I'm having a problem where my left sender unit is reading erroneously so I ran out of gas when it stuck at 33L.

I believe you are having a similar problem but on the right sender.

Put in 10L or so of gas it should be enough to register 5L or so on the left. You can use test six as a fuel gauge until you fix the problem. For the last 1/3 of a tank the right gauge only contributes about 1.4L to the total so the left reading really is everything.

Open up right side, hook up the connector when you have the pump assembly out and test six running. Sweep the sensor arm and it should swing from 0-27L. You may see a broken wire on the resistance bar but I can't remember if open is high or low.

If the resistance bar is broken open and low is shorted just short out the wires until you fix it. You should get correct reading for the last 1/3 of a tank it will just never read much over half.

My gauge read about 7/16 tank when I ran out of gas but tank was so empty I could have gotten the remaining fuel out with six paper towels.

After I filled up the left side read only 28 and supposed to be 55 full. After I drove a bit it sprung up to 55. Right side 27. The gauge still read wrong until I reset with test 21.

The erroneous reading should't affect the pressure, should it? It was a new unit as of last August. Does it seem odd to have 0 on the left as well?

It affects the pressure because the tank is none dry. You cant have more than 1.4L of gas on the right side and 0 on the left. Anything over 1.4 on the right spills to the left.

With the right side pegged to max you'll get about 1/3 tank on the needle but as left drops to zero you get no indication of empty tank until the engine stalls.

There might be six oz of gas at the foot of the pump to get just enough to get the engine to catch once and and stall.

It's possible a different faikure has happened but I had the exact symptoms you describe but from the left sender sending too high of a reading. You will most likely see a bone dry tank when you open the port. No reason to open the left side if you put some gas in and the test six shows left reading.

06 4.4i no fuel pressure
 

Not odd zero left. Confirms my theory. The siphon jet did its job and moved every drop of fuel from left to right. The pump then sucked the right bone dry becuase the sender was reporting an extra 27L not there you had no idea.

Better right misreading than left like mine. When left misreading the right reads. Only about 1L for the last 1/3 of a tank and for the last 100 miles or so I have no idea how much fuel I have. Test six reports about 0.6-0.8L the entire time except when the car is moving, much of the time it will actually read zero. Talk about high anxiety.

BMW has a repair bulletin how to repair when it's acting like mine (basically add spring pressure to the sensor wiper arm) but yours appears broken so reading full scale high. If the break is obvious you might be able to repair.

Did you replace the whole sender unit or just the pump? If whole unit the defect should be warranty covered. If not, then if the break is not in the wiper zone you may be able to solder it (obvious heat + fuel precautions required)

Of course I find that I have two 5 gal gas cans and of course both are full of regular lower octane gas....

My options are to use the 87 or so octane or go buy yet another 5 gal container and fill it with the correct gas.

It was the complete unit with sender. Since I had it open to check voltage to the pump, I went ahead and pulled it and you are correct. Bone dry. Wires look intact as do the wipers and tracks. About to check with meter.

Sender reads 19.7 ohms empty and sweeps up to infinite. Seems good. So am I looking at a short somewhere? That will be a pain to track down.

After putting it back together, its now reading correctly- 0.0 0.0 0.0. I pushed and pulled on the sender to see if it would go infinite at empty but it didn't happen. Odd. Bad contact in the connector? The pins looked a little oxidized, but not that bad.

Supposed to be like 450 Ω max


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