Make sure the Crossbleed valve is set to Open. Make sure packs and recirc fans are off. Make sure APU and engine bleeds are on. You might need to spool up the left engine a bit to start.

Make sure the Crossbleed valve is set to Open. Make sure packs and recirc fans are off. Make sure APU and engine bleeds are on. You might need to spool up the left engine a bit to start.

Engine bleeds need not be on for APU start.

Saves me forgetting to turn them on later :(

Recirc fans are electric items linked only to te air conditioning air recirculation after the packs (they collect air in te cabin, filters and put inside te mixing manifold to be sent again in the cabin. These have nothing to do with engine start.For apu start engine bleeds can be either ON or OFF. The only important thing is to leave OFF the APU bleed. and, if left engine is running, never use a dual bleed configuration (Amber light) so, for the left side use only one source, or the APU or the engine.

AUTO logic was posted few posts above, seeing it you will understand that to let the ISOL valve to AUTOMATICALLY open for a cross engine start, you simply need to put one of the following switches to OFF to automatically open the valve:ENG1 Bleed ORENG2 Bleed (obviously for cross start you must leave the running engine bleed on) ORLH pack ORRH pack . This means that in all conditions, on ground, when starting an engine the valve in AUTO position is always open because, bleed or not bleed, the packs are OFF.Also if you want to use both packs with only the APU running, you can turn off one of the engine bleed, the apu will feed both packs, same as forcing the isol valve in the open position.737 has not too much automatic systems, but it is strange that if there is one with an automatic feature, it is disregarded by a lot of people. :)

Make sure the Crossbleed valve is set to Open. Make sure packs and recirc fans are off. Make sure APU and engine bleeds are on. You might need to spool up the left engine a bit to start.

Yikes. Don't run the engine above idle with the APU bleed open.

Yikes. Don't run the engine above idle with the APU bleed open.

Which leads me to an off topic question. If a back pressure scenario exist (engines past idle with dual bleed light) will the APU respond appropriately on the NGX? ie possible automatic shutdown due to over temp. I can't test now as I'm not at home.

Yikes. Don't run the engine above idle with the APU bleed open.

I knew something was wrong as soon as I posted that! I forgot that APU bleed shouldn't be open when doing that. I'd make some NG pilot

I'm also having APU starting problems, LOW PRESSURE lights up and can't even get ground power to start up engines, and have reset all failures, went to the extent of un-installing and re-installing but still the problem persists... Please help me, I NEED TO FLY!!!Leandro

The Low Pressure lamp should light for a second a bit as the APU spools up. Are you allowing it to start or are you setting the APU to off when you see the lamp?Are you using Ground Pneumatic source and not Conditioned Air?Are your Air Conditioning Packs OFF?

Check you removed the pitot covers!! Not sure if I'm confusing sims, but if you start the APU with the covers on, the APU will fail to start due to bad intake air (i.e. the APU door is still closed)!I had a bad start the other day for no good reason, and all failures were disabled. I think the reason was covers.EDIT: I just tried with the covers on and it started OK. I seem to recall I did not HOLD the switch in START, but only clicked it at the time of the failed start.Best regards,Robin.

I know that much, the APU does not spool up, I do allow it to start, I'm not using ground sources at all, Air Conditioning packs are off!!!I'm starting from COLD AND DARK!!! Still the problem persists!!!

Edited February 13, 201214 yr by Pestanas

Check you removed the pitot covers!! Not sure if I'm confusing sims, but if you start the APU with the covers on, the APU will fail to start due to bad intake air (i.e. the APU door is still closed)!I had a bad start the other day for no good reason, and all failures were disabled. I think the reason was covers.EDIT: I just tried with the covers on and it started OK. I seem to recall I did not HOLD the switch in START, but only clicked it at the time of the failed start.Best regards,Robin.

What covers do you refer to? I don't seem to be able to hold down the switch in START, I have never had to do that before!!! These problems all started after I formated my PC and re-installed everything!! :(Leo

He was supposing that in the NGX was simulated the APU intake cover (wich as far as I know it doesn't) that will be installed when you set the pitot covers from the menu.Same for the switch, I tried to hold to the START position but always returned to ON after half second. The APU will miss to start (with a fault) if it was already started, shut down and started again within few minutes. In this case I think that the fault triggers too often, but, I can live with it.

 

These problems all started after I formated my PC and re-installed everything!!

Did you update your FSX installation to SP2? Coulda missed that. Were you prompted with a activation message after re installing the NGX?Do you have any issues getting the aircraft up and running using just external power and pneumatic air?If you do have issues getting things up and running, I'm thinkin there could be an activation issue here.