IO320 Help

[Elwell81]

I made my first flight today and had an interesting event occur. I climbed up to 6500 ft to just do some quick stalls and then come right back down for landing. However, when I started to level off and pull the throttle back, I got to about 1400 rpm and the engine died. I tried everything thing to get it back but it would just crank and not start. I was about to shut everything down and prepare for a dead stick landing (I was directly over the airport) when I decided to try to restart like I would on the ground, with the mixture in idle cutoff. It came to life and ran better with the mixture pulled out quite a bit from full rich. I left it like this all the way to the ground and had no more problems.

Any opinions on what might have happened?

Its a Superior XP IO-320 with dual P-mags and Silver Hawk EX. I've got the data-log from the G3X touch through entire sequence of events so if any additional info is needed let me know. Thanks

[Mike S]

Originally Posted by Elwell81

I made my first flight today

Andy-----------congrats on the new fledgling

[Elwell81]

Originally Posted by Mike S

Andy-----------congrats on the new fledgling

Thanks, I appreciate it. Definitely a little more exciting than I had expected.

I just hope somebody has some ideas on the engine issue.

[cajunwings]

Initially sounds like fuel system is dumping way too much fuel thru engine and over rich mixture is putting the fire out. The Bendix RSA servo's have exhibited this failure mode. More info is better, did this happen on first flight with just 20 minutes on new plane and engine? Do you have EGT and fuel flow readings up to power interruption? And after relight? Look at Fuel Vents yet? Did you switch tanks on this flight?

Don Broussard. A&P, IA

RV 9 Rebuild in Progress

[Elwell81]

Originally Posted by cajunwings

Initially sounds like fuel system is dumping way too much fuel thru engine and over rich mixture is putting the fire out. The Bendix RSA servo's have exhibited this failure mode. More info is better, did this happen on first flight with just 20 minutes on new plane and engine? Do you have EGT and fuel flow readings up to power interruption? And after relight? Look at Fuel Vents yet? Did you switch tanks on this flight?

Don Broussard. A&P, IA

RV 9 Rebuild in Progress

To answer your questions, yes, happened on first 20 minutes on new plane and new engine. I had 30-45 minutes of ground run before first flight. Fuel flow at take off peaked at 13.6 gph @ 2400 rpm, with EGT's from 1205-1285.

After restart, the fuel flow was 4.5 gph @ 2000 rpm, with EGT's from 1300-1390. This was leaned quite a bit.

I switched tanks when trying to restart, from left to right, and it finally restarted. Although I believe it had more to do the mixture setting than anything. The boost pump was on through the whole event and the fuel pressure never dropped below 28 psi. Would it still maintain fuel pressure if there was a venting problem? The vents are per plans. Thanks for your help.

[mahlon_r]

Make sure the vent in the flow divider isn't blocked!
Good Luck,
Mahlon

[cajunwings]

By the way, congrats on your first flight and successful return to Earth.

Logic says this has to be either ignition or fuel trouble. Sounds like wing tank fuel venting is probably OK but take off the fuel caps and by mouth pressure up the tanks verify vents are clear. Mahlon has a good suggestion as well Do you have EGT & FF data @ 6500' right before power reduction and engine quitting? Where was the mixture set during the climb? When the engine quit did it run rough and die or stop instantly like you turned off the mags? Will it now make full power on the ground and give you the same EGT & FF as before?

[Elwell81]

Originally Posted by mahlon_r

Make sure the vent in the flow divider isn't blocked!
Good Luck,
Mahlon

Now that's something I hadn't thought of, mainly because I didn't know there was one. Is it fairly obvious on the flow divider? I remember seeing a blocked off port that says "pressure" I think, but nothing else. I will pull the top cowl and take a look.

[Elwell81]

Originally Posted by cajunwings

By the way, congrats on your first flight and successful return to Earth.

Logic says this has to be either ignition or fuel trouble. Sounds like wing tank fuel venting is probably OK but take off the fuel caps and by mouth pressure up the tanks verify vents are clear. Mahlon has a good suggestion as well Do you have EGT & FF data @ 6500' right before power reduction and engine quitting? Where was the mixture set during the climb? When the engine quit did it run rough and die or stop instantly like you turned off the mags? Will it now make full power on the ground and give you the same EGT & FF as before?

It didn't die like a killing the mags, it seems like it was fuel related, either to little or too much. Mixture was full rich except for one brief moment in the climb when I leaned it a bit to see if I had any rpm gain. Here are a couple snapshots of the logs. It runs fine on the ground, haven't seen any changes in FF or EGT. Going to check the fuel vents and flow divider vent today when I get to the hangar.

[skylor]

Originally Posted by Elwell81

It didn't die like a killing the mags, it seems like it was fuel related, either to little or too much. Mixture was full rich except for one brief moment in the climb when I leaned it a bit to see if I had any rpm gain. Here are a couple snapshots of the logs. It runs fine on the ground, haven't seen any changes in FF or EGT. Going to check the fuel vents and flow divider vent today when I get to the hangar.

It appears that something disrupted fuel flow. One thing you don't show in your data is manifold pressure. If you can't find any fuel system related issues, I would look carefully at your induction system and make sure you don't have something loose in your air box partially or intermittently obstructing your FI servo inlet.

Skylor