PMDG FUEL IMBALANCE TROUBLE SHOOTING

[Guest Sartori23]

All right, Did some testing last night and this is what I found. When the center tank runs dry the engines die. After the center tank pumps are shut down and the engines restarted, you can turn the center tank pumps back on without the engines dying. The imbalance issue appears to be caused by running the APU. It pulls about 10lbs or so a minute from the right wing tanks. I started cold and dark,used the APU to power up the aircraft until after engine start. I noticed in the time it took to get everything up and running and get my flight plan loaded into the FMC the APU had consumed 230lbs of fuel from the right tank. The imbalance stayed at 230lbs with the APU shutdown. About 20 minutes after takeoff I fired up the APU to see if the imbalance would increase in flight. Sure enough, with the APU running for about 7~8 minutes, the imbalance went from 230 to 300 lbs.Hope this helps.Carl Moore

[Guest Darren Howie]

G'dayHere are my settings.I experienced a No 2 flameout on expiration of fuel in the centre tank.My data:1) FS2004 on Win XP Home2) Yes3) No4) FS2004 aircraft fuel menu5) 6500-500-65006) No7) APU on ground prior to start.Turned of prior to t/o.8) Flameout at centre tank expiration.9) Yes i have SU1.1All the best and keep up the great work on the NG of flight sims.Darren Howie

[Guest]

1.) FS2K22.) No unlimited fuel3.) Yes, shutdown and start-up on a second leg, did not use the center pumps and the first.4.) Fuel menu?? I only know of one within FS, not fuel settings at start-up.5.) Full-1500-Full6.) no, not on 2nd leg, on first leg yes about 1hr prior to balance the wing tanks after APU operations.7.) yes, it was off when flameout occured.8.) Right engine flameout.9.) YESSIR.Eddie Doloughty

[Guest iandavid]

To add to my post on imbalance.I suffered from continual engine shutdowns with no fuel in centre tanks and I thought it was pilot error. I appear to have solved the flameout problem - not the imbalance by doing the following.I loaded up the default 737-400, powered up and started engines. I then did a complete shutdown (ctrl+shift+F1) to shut of the fuel and turned all power off. I saved this flight as a "cold and dark pre PMDG" flight.Now when I'm in FS9 and want to fly I select the above flight and then go to the PMDG 737. So far I've had no flameouts. This may well be a red herring but there may be something in this which will give a clue to the problem, I don't know.Just my two pennys worth.Paul gardner

[Guest Glaudrung]

Ok, here we go:-startup at ksea on runway with engines shut down.- running Fs9- no unlimited fuel (I can run out ouf fuel and then engines should shut down)- I didn't set any fuel valves in the menu of Fs9. Inside the cockpit all fuelpumps were "on" and no crossflow applied- I used the pulldown menu from Fs9 to adjust the amount of fuel to- both wingtanks to a full 100% and the center tank to only 5% (for test reasons only)- again no crossfeeding- I used the APU to start engines and after both engines running I shut the APU down. This resulted in a slight imbalance between the right and left wingtank. (left lower than right = normal)- takeoff with full power... both engines pulling fuel out of the center tank... when this went dry, flameout of both engines... No imbalance except for the slight difference between left and right because of apuLuc "Glaudrung" BrusselmansBelgium

[Guest Glaudrung]

By the way...is there some other way to adjust the fuel, other than the pull down menu from Fs9 to adjust fuel and payload...???I have been wondering about this since I first read this thread...Luc

[Guest]

Hiafter looking to the default Boeing 737-400 from FS9 I notice, that in the aircrfat.cfg the number of tank selector is = 1After changing our PMDG to the number 3 I got back to 1.And ?I tested ( 2 times only ) and it works.When the center tank goes dry, you get the message "fuel", I shut down the pumps of the center tank and the engines run now from the wing tanks, without any problems.Try it !Gerhard / Vienna

[Guest AirbusBuff]

Why is it that the left tank is hard limited to 29% of capacity with APU on? Technically if all tanks are full and the APU is drawing off left, from 100% there will be an imbalance and why no other pumps are turned on except aft 1. Once APu is cut out, xfeed oughta balance the 2 wing tanks in flight.APU should not be drawing fuel at a high rate or constant rate even if left on in flight since fuel economy varies with altitude.Can you check this out. I try to fill left tank for flight but hard limited to 29% max until I shut it down.

[Guest Ian_Riddell]

"Can you check this out. I try to fill left tank for flight but hard limited to 29% max until I shut it down."This is a known bug, Mr ...er... "Buff". It has been mentioned many times in the forum. Pausing the sim with the "P" key before refilling the tanks will allow you to put in as much fuel as you want ;-)Regards.Ian.

[Guest GeoffC]

** If you already have this post apologies.Robert,I have had the flameout problem many times and seem to be able to re-create it. Basically I tend to load the flight from create flight and once loaded adjust the fuel. Now my logic here is based on a PSS and I think Dreamfleet issue, but don't quote me. Basically in one of them if I set the centre to zero and the wings to say 30% the engines would shut down. To avoid this I always left 5% in the centre and the problem goes away.Tonight I tried two flights from EGCC runway 24R with Activesky running (I hope this isn't too much detail). I ran this up from create flight and once loaded altered the fuel to 30% 5% 30%.I then spent some time setting up the FMC to fly to EGNM (A very short trip of 40nm). After doing that and setting the MCP I taxied to the runway. It seemed to be burning centre tank fuel very fast as I was down to 200LB by this point. I only came to this conclusion when I did the whole thing again and it burned more slowly.Anyway, with everything setup I got onto the runway and started to roll. Between 80kts and V1 the centre tank emptied and I lost engine 2 (As always). Due to my piloting ability I veered right and game over. One point here, I never get an audible alarm and I don't know if I should. If not I would like to recommend one to Boeing.After all this excitement I did the whole thing again, however the centre tank lasted much longer so I took off. Part way into the flight the centre tank emptied and engine two died. On this occassion I restarted and landed safely at EGNM as you will be glad to hear.I took screen shots of the panel and overhead during both flights if you would like them for reference. Please let me know and I can email them. I wasn't sure what the protocol is here regarding attachments. I will now answer you settings questions:1) What version of FS are you using?20022) Do you have "unlimited fuel" deselected? (I ask because after tens of hours of testing in FS9 I realized I had this box checked....duh)Yes3) Have you manually set the fuel valve within MSFS before/during your NG flight?Before flight4) Which fuel menu did you use to set your fuel leve?Inside flight sim before take off5) What was the fuel level in each tank approximately at Takeoff...30% 3% 30% and second time30% .5% 30% 6) Had you conducted ANY crossfeed operations during the flight?No7) Had you operated the APU at any time during the flight? Was it On/Off when the flamout occurred?No and off8) Did you experience IMBALANCE, FLAMOUT or both?Flameout9) Please tell me you are running SU1-1, right? YepI hope this helps solve the problem.RegardsGeoff

[Guest Steve_Park]

Well, after about a hundred flight's in the NG, it finally happened to me. I was departing on a flight from KSEA to KBOS (AA230) and started at the gate with engine's running. Aircraft was 737-700 2D Cockpit-American Airlines. After getting in the cockpit, I set up the FMS, configured upper panel (Light's, window heat, cabin power, SB/NS Sign's). Started SBRelay 1.1, SBHost.dll, and SBMain.exe, Roger Wilco, connected to mulitplayer, host, internet, etc for online flight. After programing the FMS, I removed about 10,000 lbs of fuel from the center tank, wing tanks at 100%. About 3 hour's into the flight (while I was in another window checking servinfo in vatsim) I noticed that I was losing altitude. Back in the cockpit and had suffered a double flame out and was decending out of FL330. I fired up the APU, configured the bleedair for restart and lost only about 8,000 feet before I got the first engine back on line. Re-engaged GEN1, AP, and ALT HOLD. Got engine 2 fired up, got electric's back on line, cleared alarms, turned off APU and began climb back to assigned altitude. Now, WHAT HAPPENED. I had always in the past gotten a fuel message when the center tank ran dry, but this time, double flameout.1) What version of FS are you using?FS9 on Win XP Home/SP1, FSUIPC 3.06 (registered version), DX 9.0b2) Do you have "unlimited fuel" deselected? (I ask because after tens of hours of testing in FS9 I realized I had this box checked....duh)Yes3) Have you manually set the fuel valve within MSFS before/during your NG flight?Before flight4) Which fuel menu did you use to set your fuel level?Aircraft->Fuel pull down within FS5) What was the fuel level in each tank approximately at Takeoff...100% - 70% - 100%6) Had you conducted ANY crossfeed operations during the flight?Yes, after double flame out and APU start to restart engines, had about a 1100 lb. imbalance Right - 7760 Left 6620. Used crossfeed to correct imbalance. 7) Had you operated the APU at any time during the flight? Was it On/Off when the flamout occurred?Yes and OFF8) Did you experience IMBALANCE, FLAMOUT or both?BOTH9) Please tell me you are running SU1-1, right? YesSteve ParkKSDF

[bobbyjoh 11]

Hi Robert and fellow PMDG pilots,I too have had this situation occur. One item that still concerns me from Robert's original post is that he cannot get this to occur. I think we should have a review of what is the test aircraft.cfg and what everyone else is running. One thing many of us changed was the number o fuel selectors. In the early days of the 737NG, we changed it from from the original 1 to 3. That may have helped the fuel imbalance problems. However that was fixed with the patches. Now none of us know what is cuasing the flameout problems.Here is my response to Robert's question;1) What version of FS are you using?FS2004 under Windows XP Pro2) Do you have "unlimited fuel" deselected? (I ask because after tens of hours of testing in FS9 I realized I had this box checked....duh)No 3) Have you manually set the fuel valve within MSFS before/during your NG flight?No4) Which fuel menu did you use to set your fuel level?I use the FS Aircraft options setting for fuel load5) What was the fuel level in each tank approximately at Takeoff...100% left and Right Wing and 40% Center6) Had you conducted ANY crossfeed operations during the flight?NO7) Had you operated the APU at any time during the flight? Was it On/Off when the flamout occurred? I turn on the APU during pre-flight for electrical power and then to start the engines. I turn it off after engine start. It was never on during flight8) Did you experience IMBALANCE, FLAMOUT or both?I got a fuel imbalance, but that was from fuel being used by the APU during preflight. I did get a flameout during flight when the center wing tank went to empty.9) Please tell me you are running SU1-1, right?Yes I running SU1-1.This is a real mystery, why it can't be reproduced by everyone.CheersBob JohnsonDenver

[erict 9]

My first two flights with this product I experienced double flameouts when the center tank emptied. The first time was right after takeoff around 4000 feet! Scared the hell out of me. =P1) What version of FS are you using?FS2002 on Win XP Pro/SP1, FSUIPC 3.06, DX 9.0b2) Do you have "unlimited fuel" deselected? (I ask because after tens of hours of testing in FS9 I realized I had this box checked....duh)Yes3) Have you manually set the fuel valve within MSFS before/during your NG flight?No4) Which fuel menu did you use to set your fuel level?Create flight --> Fuel settings5) What was the fuel level in each tank approximately at Takeoff...100% - 30% - 100%6) Had you conducted ANY crossfeed operations during the flight?No7) Had you operated the APU at any time during the flight? Was it On/Off when the flamout occurred?Yes and OFF8) Did you experience IMBALANCE, FLAMOUT or both?Flameout9) Please tell me you are running SU1-1, right? Yes, definitelyGreat product BTW, needs some tweaking like most complicated panels.Cheers,Ericwww.virtualATP.org

[bobbyjoh 11]

New Twist to this problem. Today I flew from KMIA to KEWR (Miami to Newark). My fuel load was 21446 pounds. I set fuel via the FS9 options aircraft fuel with 100% in both wing tanks and 15% in the center wing. I also made a change in my 737-700 aircraft.cfg and set the number of tanks back to one from three AS THE ORIGINAL PMDG 737 CFG WAS SET.After takeoff, I forgot to check the fuel levels and ran out fuel in the center wing tank shortly after level off. To my surprise I got an annunciator light for fuel, and an fuel feed switch to the wing tanks and NO FLAMEOUT!!!!!This has NEVER happen since I have had the 737, however I have never had the aircraft.cfg set to one tank either. Could this be the culprit of the PMDG team not seeing the flamout problem and the rest of us seeing it? I will test again tomorrow to see if this happens again.Hope this helpsBob JohnsonKDEN

[Guest Fltsim Phil]

Robert:I experienced a flameout for the first time this weekend flying the "Advanced Tutorial" as described in Tim Metzinger's posting. Here were my settings:Version: FS2002 with SU1-1 updateFuel levels at takeoff: L&R Tanks-100% Center Tank-20%, no crossfeed operations at any timeAPU: Ran at start-up, switched off during taxi to takeoffApproximately 20-30 miles before reaching BNA VOR, the center tank fuel exhausted, I received a caution "FUEL" light on the annunciator panel, and the RIGHT engine flamed-out. Fortunately I was able to restart it with no altitude loss since the LEFT engine was still running and the FMC was flying the plane.I will attempt the flight again either tonight or tomorrow night. I hope this information is helpful.Flightsim Phil