Sometimes engines just motor and won't start

[kneighbour]

I mentioned in another thread that sometimes the engines will not start. Best to start a new post, I thought.

 

Tonight I did 3 starts, 2 on external power and 1 on battery. The first one on ground power failed. The other two worked just fine.

 

I all cases I used the checklist and to the best of my knowledge did not miss any steps. But it is possible.

 

One thing I have noticed. When you press the START switch, the engine starts to motor up. The Temp goes to about 29 degrees and stays there and the RPM goes to 20% and stays there (forever).

 

Also, within a few seconds you hear a pretty strong blast of air (if it is going to work). I don't know where this air comes from, or indeed if it is an air blast at all.

 

If the engines are not going to start, this 'air blast' does not occur. You then have to reload the aircraft (with all that entails).

 

I know it is not much to go on, and it does not happen very often, but perhaps other users are seeing this as well and have noticed something I have not?

 

And by 'not often' - it has happened perhaps 3 or 4 times in the last 10-15 starts.

 

V1.3 in Windows x64. XP 10.36.

[JGregory]

Kerry,

 

I mentioned in another thread that sometimes the engines will not start. Best to start a new post, I thought.
 
Tonight I did 3 starts, 2 on external power and 1 on battery. The first one on ground power failed. The other two worked just fine.
 
I all cases I used the checklist and to the best of my knowledge did not miss any steps. But it is possible.

Have you ever used the Auto_Start feature?  I'll bet the aircraft will start correctly EVERY TIME you do!  If it doesn't then something in your system is interfering with the proper operation of the Saab (hardware perhaps?, another plugin?). However, if it does start every time you use Auto-Start then what does that tell us? ... most likely user error, especially since I have not heard of this problem from anyone else.

 

Page 125 of the manual clearly states the following... "Hold the START switch to L or R position for two seconds and release."  Not doing this could certainly result in an engine not starting.  In addition, if the condition lever is in the fuel cut-off position the engine will not start.

 

One thing I have noticed. When you press the START switch, the engine starts to motor up. The Temp goes to about 29 degrees and stays there and the RPM goes to 20% and stays there (forever).

Right... so the starter motor is running but it sounds like there is no fuel and/ or no ignition.

 

Also, within a few seconds you hear a pretty strong blast of air (if it is going to work). I don't know where this air comes from, or indeed if it is an air blast at all.
 
If the engines are not going to start, this 'air blast' does not occur.

It's not a blast of air, it's called "combustion", and it's a good thing.  If you don't get combustion you will not get an engine start.

Edited June 27, 2015 by JGregory

[kneighbour]

Have you ever used the Auto_Start feature?

Only a couple of times. Worked each time. But have not used it enough to build up a history.

 

"Hold the START switch to L or R position for two seconds and release."

Yep  - that is what I do. Probably even a bit longer.

 

 

 

Right... so the starter motor is running but it sounds like there is no fuel and/ or no ignition.

Ok. Since that noise I hear on a good start is combustion firing up, that makes sense. I originally thought it was lack of fuel causing the problem, because when it goes into start sequence, the fuel gauges turn off. But that is just the gauges turning off.

 

I certainly have the Condition levers on the indent. Also have enough fuel. So not sure what else to check. Oh - one thing there - I always put BOTH condition levers on the Start line, plus the throttles on Idle.

 

If one engine does this, the other engine will be the same. ie neither will start.

 

If nothing else, surely the engines should not motor on forever? Is there not a timeout function in the startup sequencer? Having to reload the aircraft seems a bit extreme.

Edited June 27, 2015 by kneighbour

[JGregory]

Kerry,

 

As I stated previously... Auto-Start is the key to diagnosing where the problem is coming from.  It has worked for you every time so far.  Try it again... I'm sure it will continue to work every time.  So, if Auto-Start works then the Saab is working properly and there is something on your end that is not working, which may also be causing the starter to run on endlessly.  I can't diagnose your system for you.   No one else is reporting engine start problems.

[kneighbour]

I was not even intimating that there was anything wrong with the systems (except for the fact that once it starts motoring, it goes until doomsday). I fully agree it is something I am doing. Using Autostart will not help in diagnosing that. I don't think it is a checklist item as they are all pretty much digital - ie I either do them or I do not.  And I do them.

 

My current hypothesis is that I am not accurately lining up the Condition levers. They certainly LOOK like they are lined up, but will try to play with slight misalignments and see if that is the issue.

 

Did 3 starts yesterday, no problems.

[ryanbatc]

Try the popup throttle position picture (it should be on the gizmo sidebar thing)...  maybe your peripherals are slightly off.

[kneighbour]

Try the popup throttle position picture (it should be on the gizmo sidebar thing)...  maybe your peripherals are slightly off.

Yep - that is what I plan to do.

[alpha12125]

just to chime in, i have had this problem a few times ( 5 times out of 100), but sofar it is not reproducable for me.  i do everything by the checklist and then i start the engine and the temp starts rising to 30 degree and just stops but the sound will continue and then stay at a constant level, like there is no fuel injection though. this happens to always one engine not both. I stop the start procedure and the other engine will start normally. However the faulty engine wont start no matter what i try. I have to reload the airplane and it will work 100% everytime.

 

It does happen very rarely and while i can't rule out that i did something wrong on the startup, i go by the virtual checklist everytime. I will try to figure out some reproduction steps, if it happens the next time. But like I said it does happen rarely for me.

Edited June 29, 2015 by alpha12125

[kneighbour]

Good to hear that other users having the same/similar problem. I don't feel quite so stupid!

 

Usually when it happens to me, neither engine will start once one fails to start. But now I know not to bother - I know i have to do a reload, so perhaps sometimes the other engine will start sometimes.

 

I stop the start procedure and the other engine will start normally

Not sure what you mean here. How do you stop the start procedure? One of my issues is that the engine will stay in motoring mode for ever. I have had the battery down to 10V and dropping. I have even turned both batteries off then on again - the motoring continues unabated. This is with no external power. Edited June 29, 2015 by kneighbour

[AlphaCharlie]

Hi,

 

This happens to me very sporadically as well. Similar sort of incidence to what alpha12125 describes and similarly, only 1 engine that becomes inoperative.

Generally, a Gizmo reboot or Aircraft reload from the X-plane menu will resolve the issue though on occasion, I have needed to reload X-plane to clear the issue.

So far with v1.3 this has only happened once since installing making this a tricky customer to pin down and reproduce reliably, but the frequency has definitely decreased substantially since upgrading from 1.2 to 1.3.

 

Just wanted to let you know you are not alone guys

 

To the devs - I appreciate there's not a lot to go on here, but will post back if I find anything interesting in the logs or am able to reliably reproduce.

 

Thanks,

Alex

[kneighbour]

Had another 'dry start' last night. First flight - ie just loaded up X-Plane and first and only aircraft loaded was the 340A passenger variant.

 

This time I checked the Condition Levers with the  Trq Popup. They were EXACTLY on the line, as was the throttle. So misalignment there does not seem to the the issue.

 

Once I reloaded the aircraft and started ok, I had another 'problem'. As soon as I started the Left engine (first), the hydraulic pump came on and stayed on (I was not sure what that sound was at the time, so I took off).

 

I took off and after a short time I got a Hydraulic system failure on the fault panel. I turned off the Hyd Pump manually and all was fine. Hydraulic pressure was 0 though. If you turn the pump on, it fires up and the pressure goes from 0 to 2900 ok. But the pump does not turn off. I turn the pump off manually, and all is fine for a few minutes. But the pressure bleeds out, so after a short time (minutes), the warning light comes on again. I fired it up just before landing to get pressure in the system for the landing gear/flaps and landed ok.

 

Image 1 is early in the flight. 0 in the Main Accumulator, and the Mechanical Accc normal.

 

Image 2 is near the end of the flight. The Main Acc had been pumped up and is slowly dropping down to 0. The Mech Acc is right up - so do not knows what that means.

 

I only mention all of this in case it has some bearing on the engine start issue. Having a fault in flight like this is really nice - very nice touch if it was a random failure.

Edited July 4, 2015 by kneighbour

[JGregory]

Kerry,

 

I need reproducible steps in order to diagnose this problem (or any problem, for that matter).   I appreciate the report but, without defined steps to reproduce the problem, any attempt to fix this would be like finding a needle in a haystack.

[kneighbour]

I need reproducible steps in order to diagnose this problem (or any problem, for that matter).

As a software developer myself, I can appreciate your desire for a perfect world. Perhaps if you approach the problem from the other direction. What conditions will stop combustion, and perhaps just as importantly, what makes the engine motor until the heat death of the universe? The motoring problem would not be so bad if it stopped in a realistic time, and as I imagine it does in real life. Then the start could be attempted again.

 

Perhaps I can check these inputs before each start - perhaps even putting some variables up on the screen (if possible) to check.

 

Mere suggestions

[Jakob Ludwig]

Kerry,

 

I need reproducible steps in order to diagnose this problem (or any problem, for that matter).   I appreciate the report but, without defined steps to reproduce the problem, any attempt to fix this would be like finding a needle in a haystack.

 

I may have a hint, as I got into this "issue" (may not call it like this) this morning. I flew with a different aircraft before (a single engine piston), which I shutdowned by cutting down the fuel with the mixture lever on my ch hardware throttles. Than I loaded the key and axis assignment config for the SAAB, with a plugin called X-Assign (I have 3 global configs, main difference is axis assignment for engine control). My Saab config has only the throttles axis assigned for each engine and no other engine control axis (prop, condition, mixture). 

 

This resulted in loading the SAAB with fuel mixture cut-off by the aircraft before, concluding an impossible start-up with the Saab. I changed my config back (where I have mixture control), brought the mixture lever to its full position, changed the config again and than like magic, the SAAB ignited both engines with no problems at all. 

 

So it looks to me, that the SAAB condition lever is unable to allow fuel flow, once the mixture control was set to zero with the aircraft loaded before the SAAB. 

[JGregory]

I may have a hint, as I got into this "issue" (may not call it like this) this morning. I flew with a different aircraft before (a single engine piston), which I shutdowned by cutting down the fuel with the mixture lever on my ch hardware throttles. Than I loaded the key and axis assignment config for the SAAB, with a plugin called X-Assign (I have 3 global configs, main difference is axis assignment for engine control). My Saab config has only the throttles axis assigned for each engine and no other engine control axis (prop, condition, mixture). 

 

This resulted in loading the SAAB with fuel mixture cut-off by the aircraft before, concluding an impossible start-up with the Saab. I changed my config back (where I have mixture control), brought the mixture lever to its full position, changed the config again and than like magic, the SAAB ignited both engines with no problems at all. 

 

So it looks to me, that the SAAB condition lever is unable to allow fuel flow, once the mixture control was set to zero with the aircraft loaded before the SAAB. 

Jaggo, 

 

Excellent reporting, thanks for that.  I will have a look into this and let you know.

[kneighbour]

For me it has always been the first flight of the day. I am only flying the 340A, and I do nothing special with assigning axis controls.

[Polar1955]

So what are you telling us we should do, push the condition levers for the CH axis to the full up, before assigning them? I will try starting with condition levers full forward ( and using only SAAB controls) then after start if successful will assign levers for the CH axis. You may wish a step by step procedure so as to make it clear as to what to do. If I read you correctly, this is something I looked into and tried, I will try again so as to see if it does fix the problem.

 

 

I got a good start using the above procedure as I outlined, I will nn to try this many times to see if your idea continues to work as I have had times where I can get multiple starts before encountering another bad series  starts. Thank you for your idea, hope this is the fix

Edited July 9, 2015 by Polar1955

[Polar1955]

Some good news:

Did not reboot computer w/ each attempt, reloaded XP for each of the 4 starts

I got 2 good starts w/ CH condition lever axis out of the detent position and levers full forward, did not assign levers till both engines started.

With CH levers in the full detent on third attempt the engines failed to start

The next attempt number 4 was a success using the new procedure.

It is late here but I did have issues assigning the condition levers, getting axis 13 okay what should have been axis 12 was getting the number 10 on 2 starts, was able to correct on the 4th. I will look into this tomorrow to insure it is not me or my axis levers.

 

Important note, the levers must be full forward before starting XP

 

Your idea seems to have real promise here, good work

Edited July 9, 2015 by Polar1955

[JGregory]

Polar,

 

It is late here but I did have issues assigning the condition levers, getting axis 13 okay what should have been axis 12 was getting the number 10 on 2 starts, was able to correct on the 4th. I will look into this tomorrow to insure it is not me or my axis levers.

I'm not sure what you are describing here.  When you assign the CLs using the Saab pop-up, you will be told what index was assigned.  It doesn't matter what the index number is, but you do need to make sure that the lever(s) are assigned to "none" in the "Joystick& Assignment" window (as described on Page 11 of the "Introduction & Settings Manual" that came with the Saab).

Edited July 9, 2015 by JGregory

[Polar1955]

Thanks, I was aware of that and just forgot to change those settings, in any event I fired up the acrft w/ no problem, I will continue to fly the plane and if the described procedure I am following fails I will contact you. By the way, after changing the CL settings in the assignments of XP I did assign the Cl's in SAAB pop before starting the engines,( I still had the levers full forward before starting the XP) not sure why this is necessary but it works.

[kneighbour]

Polar1955, on 09 Jul 2015 - 5:52 PM, said:
It is late here but I did have issues assigning the condition levers, getting axis 13 okay what should have been axis 12 was getting the number 10 on 2 starts, was able to correct on the 4th. I will look into this tomorrow to insure it is not me or my axis levers.

This happened to me once also. One axis assigned itself to 31 as per normal. The other axis assigned itself to some random (10,11,12) axis and subsequently would not move. Reassigned several times and finally got it onto 32 as it always does. Still would not work.

 

Had to reload XP to get it to work as normal. They ALWAYS assign to 31 and 32 on my system, so if they do not, I know something is wrong.

[Polar1955]

I don't know what it is w/ this throttle system etc. but I hope I have it fixed. I am sure the developers had their reasons for the CL's being set up the way they are but not being a pro, someone will nn to explain it, I have never seen anything like that before, usually once the controls are set up it works that way for all acrft. The throttle pop up to me is very understandable due to the various throttle positions for the SAAB. 

Many Thanks to JGregory for his insight and help on this problem I hope the karma lol stays w/ me us.

[Tiger6k]

I just wanted to chime in because I just recently bought this plane for X-Plane 10.36.  I loaded the plane, clicked auto-start, and it just gets stuck at 39 degrees C and ~20% RPM.  As I am writing this, the "Do not disturb" message is just blinking, and the plane is stuck in this start-up.  

 

This is also happening every time I "reboot" the aircraft.  I have not tried restarting X-Plane yet, and the last airplane I was flying was the Bell 407.

 

I don't have any axis set up for the condition levers, as I am using all the axis for mixture and prop for other aircraft.  

 

Hope that helps!

 

A new customer,

 

Kris

[JGregory]

I just wanted to chime in because I just recently bought this plane for X-Plane 10.36.  I loaded the plane, clicked auto-start, and it just gets stuck at 39 degrees C and ~20% RPM.  As I am writing this, the "Do not disturb" message is just blinking, and the plane is stuck in this start-up.  

 

This is also happening every time I "reboot" the aircraft.  I have not tried restarting X-Plane yet, and the last airplane I was flying was the Bell 407.

 

I don't have any axis set up for the condition levers, as I am using all the axis for mixture and prop for other aircraft.  

 

Hope that helps!

 

A new customer,

 

Kris

 

Kris,

 

I believe we have found a possible issue where this may occur.  It is possible that if you have you hardware setup for other aircraft they are setting some X-Plane datarefs inappropriately.  As a workaround I would disconnect the hardware prior to using the Saab.   There are some fixes in the next update that should resolve this issue.

[alpha12125]

Kris,

 

I believe we have found a possible issue where this may occur.  It is possible that if you have you hardware setup for other aircraft they are setting some X-Plane datarefs inappropriately.  As a workaround I would disconnect the hardware prior to using the Saab.   There are some fixes in the next update that should resolve this issue.

That sounds very plausible, i am using saitek thottles aswell. might be the common ground from everyone experiencing the issue