random multiple mossfire when cold

[andrewwynn]

I got those when my CPS failed. I also had similar codes when my wife's fuel pump died.

Drive down to zero miles DATE (or at least single digits): do it where you can phone a friend for a couple gal of fuel or bring a gas can in the "trunk" in case it's the fuel pump.

I don't know why it would change when warm but the fact the fuel pump runs 100% of the time the engine is running it could be as simple as once it warms from from use it works better.

The fuel delivery system on E53 will not deliver the last 1/8 of a tank once the fuel pump gets to "end of life" an "soft fails" the usual symptoms: misfire on WOT, weird cold starts and of course "running out of gas" with as much as 1/4 of a tank (in my case about 75 miles DTE like clock work: happened twice before I figured out the fuel pump was weak not dead).

You can either verify you have enough fuel pressure coming back to the left side of your tank (I forget the requirement) or simply drive the car down to single digits DTE. An x5 will starve of fuel when it can't supply both enough pressure to run the engine (50psi) *and* supply enough volume at pressure to syphon the gas from the left side of the tank when below 30L remaining. It's very sensitive to this and as it starts to fail you might stall at 5-10 DTE then 20,40 miles and eventually 1/4 tank. If you can drive to 5 miles DTE (there is an unmeasured 5L of fuel below zero DTE that typically means you can actually go 15-20 miles past empty. I recommend performing this test semi annually. This test will rule out the fuel pump/supply.

If you haven't changed the CPS/s or if pO had done so but used other then OEM that would be my prime suspect. I've only ever replaced the one on the intake side and we have the 3.0 but both of ours failed like clock work at 130,000 miles. lean bank codes that cleared themselves.

Does the car ever actually stall? Mine would stall on slow speed throttle off situations: 5/10 mph creep through parking lot or intersection (always a crowd pleaser especially after the idiotic "unintended acceleration" scandal that introduced us to the brake interlock and the for whatever reason x5 you can't start from the 1 position! Not the most pleasant introduction to x5 ignition curiosities: stall coasting 5mph in intersection; put in N , can't start, turn key off, can't, car in N, put car in P , car jerks to a stop because you didn't brake, turn key off, turn key to start, FINALLY start the car, put in drive from N. Oops can't: not in N. Realize that you had to shift to P to get key to 0 so you can finally start the car!

Seriously!?!? Can't restart a coasting stalled car!? WTF!? Seriously!? I've driven dozens of cars at least 15 makes, this was the only one I couldn't just turn the key from 1 to 2 after putting into neutral while coasting to start. Holy shit!

Oh : it's misfire :-D


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[hpy540]

andrewwynn, thanx for the input but this is the infamos n62. i cant find a vaccume leak. now so bad even if i unplug valvetronics solenoids it goes into engine failsafe. runs so bad but very cold here. 6°F this morn. only 23° F this afternoon. not good. i cant seem to find the answer. it is on 26miles till empty. still runs but runs horrrible, i can shut off and then half throttle it. it will climb to 3-4k rpm and run. but eventually drops in rpm to a sugeimg pulsing idle and failsafe.

[andrewwynn]

Have you had a shop scan and give you a report? It looks like time to bite that bullet.

People wonder how (as computer it guy) I can have an answer so quick to some often times very perplexing issues and the answer is that I've seen it before. It might take 20 seconds for a pro to know exactly what is the problem and that piece of information is quite valuable.

Multiple random codes is starting to sound like "common denominator" e g computer brain. I would definitely get somebody with experience and a "next level scanner" (can do abs and airbag) to scan and report. Don't clear any code for a while even if you have to putt putt putt to the dealer.


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[hpy540]

If you have a scanner it runs fine once warmed up. I an unplug valvetronics, warm her up. Then plug in and hit the highway & meet u

[upallnight]

Originally Posted by hpy540

just random multiple missfire. a few codes from last week were lean bank 1 and lean bank2 but those are gone.

Although most lean codes are the result of vacuum leaks, other conditions can set lean codes. A failing fuel pump that is not able to provide the required fuel pressure can cause a lean condition. You have a starting place with the lean codes.

If you have a scanner that can display live data, I would look at the short and long term fuel trims of both banks. Maybe a clogged fuel filter is the culprit. What type of maintenance schedule have been done on the X. Is it regularly maintain, or just fix once problems start to arise.

Originally Posted by andrewwynn

Have you had a shop scan and give you a report? It looks like time to bite that bullet.

People wonder how (as computer it guy) I can have an answer so quick to some often times very perplexing issues and the answer is that I've seen it before. It might take 20 seconds for a pro to know exactly what is the problem and that piece of information is quite valuable.

Multiple random codes is starting to sound like "common denominator" e g computer brain. I would definitely get somebody with experience and a "next level scanner" (can do abs and airbag) to scan and report. Don't clear any code for a while even if you have to putt putt putt to the dealer.


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[hpy540]

although i have a laptop with gt1 i cant seem to get to anolog values with this car. I have run to down to low fuel, it has 29 miles left on DIC right now. it still runs. this thing is the most frustrating engine combo i have ever dealt with, Ferrari is easier. when puch the schrader valve on fuel rail seems right for pressure. you get used to 60psi or so.

[andrewwynn]

50psi. If much higher that means the regulator isn't working and it's not sending the excess back to the left tank. That said, extremely rare for "lifetime" fuel filter to fail on an x5. We need to get some quality scan numbers hopeful while it's "moss" firing. If it clears up once warm it has to be a solvable problem. How long does it have to warm up before it behaves? 90 seconds (sec air pump)? Does that engine use one? Or temp dependent? Chugga chugga until closed loop?


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[hpy540]

miserable untill closed loop. then ok. iwould not be against driving down to meet to see if we can solve this.

[upallnight]

Open loop means it is following a predetermine set of values for the engine and not relying on the 02 sensors to adjust the mixture. If your fuel pressure was at 60 psi and not 50 psi it could be the engine is running too rich at open loop. You will need to actually determine what the fuel pressure is and not rely on the press the schrader valve to determine the fuel pressure in the rail. You need to connect a fuel pressure gauge at the fuel rail and get an actual reading. A lot of info can be determine if you are able to view Live Data. Unable to get live data you might as well load the parts canon and fire away.

[hpy540]

Originally Posted by upallnight

Open loop means it is following a predetermine set of values for the engine and not relying on the 02 sensors to adjust the mixture. If your fuel pressure was at 60 psi and not 50 psi it could be the engine is running too rich at open loop. You will need to actually determine what the fuel pressure is and not rely on the press the schrader valve to determine the fuel pressure in the rail. You need to connect a fuel pressure gauge at the fuel rail and get an actual reading. A lot of info can be determine if you are able to view Live Data. Unable to get live data you might as well load the parts canon and fire away.

as the fuel pump is not variable voltage...... if it runs fine when warm, shouldnt be fuel pump. &, it is not just a miss, it pops and farts and both rich and lean, intake pop &exhaust pop. and only had small missfire issues before i did coolant crossover. & i did not pull Valvetronics solenoids to do coolant crossover. i have done smoke test and carb cleaner spray test.IDK.