boomer
Well Known Member
Here?s my engine tale of woe. I am looking for any things I should look at, particularly single items that could cause an engine to temporarily stop running and not restart on the ground. All input will be appreciated.
Aircraft: RV-8, IO-360 M1B, Hartzell constant speed prop, 180 hours, last condition inspection Nov 2013, no engne problem previously noted. Oil sample taken 2/2014 (good). Compression 80/78 on all cylinders (Nov 2013).
Feb 3, 2014: A short late afternoon flight(.6 hr) before an anticipated period of bad weather. Basically straight and level profile with altitude up to 5000?. Ground temp was 72 deg F. Field elevation 500?. Fuel approx 15 gal. in each wing tank.
Flight went normal until back in the traffic pattern. I entered via an overhead pattern (1000? agl , 145 ias) and pulled the throttle to idle as I rolled into a 60 deg. bank for the break. Electric boost pump was on and mixture was full rich. Kept the engine in idle until touchdown. On roll out the prop stopped. I was able to roll off the runway and attempted a restart via the start switch. Engine turned over but would not start. Boost pump was still on. I turned off the boost pump and tried various hot and cold start techniques but could not get the engine to fire. Climbed out and walked back to the hangar where I got my truck and pulled the plane back to the hangar. Before pulling it inside I tried one more start, got a tiny bit for fire (really a cough) but it would not start. I was out of time by then and had to leave the aircraft in the hangar.
Due to family illness and bad weather, I did not return to the aircraft for 10 days. I fully expected to find a broken or disconnected mixture cable, but all the engine controls were fine. Before attempting a start, I disconnected the fuel line where it enters the throttle body to check the fuel filter there. I did notice that the fuel seemed to be under pressure in that it spurted out rather than pouring as it normally does. Checked the fuel filter and fuel flow by running the boost pump. Both OK. Started the engine after reconnecting the fuel line, and it started fine after coughing a bit (probably due to air in the fuel line). Since then it has continued to run normally on the ground up to short full power runs on simulated takeoff?s.
I downloaded the Dynon D-180 data (5 sec. interval), and everything seemed normal. It seems evident that the engine stopped generating power when I pulled it to idle in the break. Fuel flow (red cube between boost pump and engine fuel pump) went from 14 GPH to 8 GPH when pulled to idle but remained at 3.5 GPH or greater throughout the pattern. It was reading 4.75 GPH when the RPM went to zero. All other parameters seem normal, and I will post a screen shot of the data in the pattern.
This episode felt just like carburetor icing, but I am fuel injected, or vapor lock, but I had the boost pump on and the OAT was 72 deg F. Also, I have run this engine on days up to 108 deg. F with no vapor lock problems.
I have since done numerous ground runs with no abnormal indications. Here is what I have checked, all without noting discrepancies (unless noted):
1. Fuel flow at entrance to throttle body, exit of throttle body, mixture cut off, and at injectors.
2. Fuel flow with engine driven fuel pump.
3. Fuel filters
4. Fuel injectors
5. Fuel lines for leaks
6. Idle setting (slightly rich)
7. Spark plugs (a little blacker than previous but clean and dry)
8. On/off/start switch
9. Magneto ground check
10. Induction tubes tight
11. Exhaust tight at cylinders
12. Cylinder oil drain hose clamps (loose but not too loose)
13. Engine ground
14. Air inlet system: filter/snorkel/throttle body
15. Fuel tank vents
I have an engine man coming tomorrow and would like to see if anyone can think of anything he should check.
Thanks in advance, John
Aircraft: RV-8, IO-360 M1B, Hartzell constant speed prop, 180 hours, last condition inspection Nov 2013, no engne problem previously noted. Oil sample taken 2/2014 (good). Compression 80/78 on all cylinders (Nov 2013).
Feb 3, 2014: A short late afternoon flight(.6 hr) before an anticipated period of bad weather. Basically straight and level profile with altitude up to 5000?. Ground temp was 72 deg F. Field elevation 500?. Fuel approx 15 gal. in each wing tank.
Flight went normal until back in the traffic pattern. I entered via an overhead pattern (1000? agl , 145 ias) and pulled the throttle to idle as I rolled into a 60 deg. bank for the break. Electric boost pump was on and mixture was full rich. Kept the engine in idle until touchdown. On roll out the prop stopped. I was able to roll off the runway and attempted a restart via the start switch. Engine turned over but would not start. Boost pump was still on. I turned off the boost pump and tried various hot and cold start techniques but could not get the engine to fire. Climbed out and walked back to the hangar where I got my truck and pulled the plane back to the hangar. Before pulling it inside I tried one more start, got a tiny bit for fire (really a cough) but it would not start. I was out of time by then and had to leave the aircraft in the hangar.
Due to family illness and bad weather, I did not return to the aircraft for 10 days. I fully expected to find a broken or disconnected mixture cable, but all the engine controls were fine. Before attempting a start, I disconnected the fuel line where it enters the throttle body to check the fuel filter there. I did notice that the fuel seemed to be under pressure in that it spurted out rather than pouring as it normally does. Checked the fuel filter and fuel flow by running the boost pump. Both OK. Started the engine after reconnecting the fuel line, and it started fine after coughing a bit (probably due to air in the fuel line). Since then it has continued to run normally on the ground up to short full power runs on simulated takeoff?s.
I downloaded the Dynon D-180 data (5 sec. interval), and everything seemed normal. It seems evident that the engine stopped generating power when I pulled it to idle in the break. Fuel flow (red cube between boost pump and engine fuel pump) went from 14 GPH to 8 GPH when pulled to idle but remained at 3.5 GPH or greater throughout the pattern. It was reading 4.75 GPH when the RPM went to zero. All other parameters seem normal, and I will post a screen shot of the data in the pattern.
This episode felt just like carburetor icing, but I am fuel injected, or vapor lock, but I had the boost pump on and the OAT was 72 deg F. Also, I have run this engine on days up to 108 deg. F with no vapor lock problems.
I have since done numerous ground runs with no abnormal indications. Here is what I have checked, all without noting discrepancies (unless noted):
1. Fuel flow at entrance to throttle body, exit of throttle body, mixture cut off, and at injectors.
2. Fuel flow with engine driven fuel pump.
3. Fuel filters
4. Fuel injectors
5. Fuel lines for leaks
6. Idle setting (slightly rich)
7. Spark plugs (a little blacker than previous but clean and dry)
8. On/off/start switch
9. Magneto ground check
10. Induction tubes tight
11. Exhaust tight at cylinders
12. Cylinder oil drain hose clamps (loose but not too loose)
13. Engine ground
14. Air inlet system: filter/snorkel/throttle body
15. Fuel tank vents
I have an engine man coming tomorrow and would like to see if anyone can think of anything he should check.
Thanks in advance, John