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Engine quit on takeoff rollout

B

bjohnson1234

Well Known Member
This morning after a normal run-up my engine quit on takeoff rollout with full throttle and mixture on my Superior XP-360. A few weeks ago I did some maintenance including repairing my air box (the filter had worn through the fiberglass) and installing the "poor man's cold air induction" from Flyboyz (http://www.flyboyaccessories.com/Poor-Man-s-Cold-Air-Induction-System-p/2107.htm). When I took the air box off I cleaned some of the build-up off the inside of the fuel injection servo with some carb cleaner. All gaskets on the induction were scraped clean and replaced with new ones. I did a test flight a week ago and didn't notice any issues during a few laps in the pattern.

On the ground after the failure I noticed a few things:
1. Briefly going to full throttle and then idle caused the engine to quit
2. Fuel pressure would sometimes drop to between 8 and 10 PSI. The boost pump restored pressure to 24-25 and it would stay around 22 when I turned it off, but it would sometimes drop back down when increasing the throttle
3. Engine would sometimes stumble when changing throttle settings. Boost pump made no difference even when non-boost pressure was low
4. Idle was smooth
5. Engine ran smooth at constant throttle, high or low

After double-checking the intake and looking for any other obvious issues, I did a high-speed taxi which ended up turning into a takeoff. The engine ran smooth for a while, but at one point felt like it was losing power on the climb. Anyone have any ideas of what the problem might be? Anyone around DVT that could help me out with it? Thanks.
 
What was the OAT and what type of fuel are you burning? Sounds sort of like vapor lock?
 
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curtis said:
What was the OAT and what type of fuel are you burning? Sounds sort like vapor lock?
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About 100 degrees running 100LL. I've certainly flown in hotter conditions in Phoenix. Vapor lock could explain the takeoff roll quit, but not the other issues. I was able to restart the engine after it quit. I also thought about water in the fuel because I just washed it, but I checked the fuel drains after washing it and then again after filling up the tanks.
 
I would check the fuel screen whether you have a gascollator or fuel filter. And fuel pickup screens in gas tanks.

I remember reading a thread several months back were a guy was having intermittent engine problems. He couldn't find anything after checking this and that so he went flying. We'll his luck ran out one day right after takeoff and severely damaged the plane with an off field landing.

If memory serves me correctly he found his gas tank pickup tubes blocked starving engine of fuel.

Fuel for thought,
Jim
RV9a
 
I'm going to check all the filters/screens and check for any fuel leaks tomorrow. What about a hardened/cracked injection servo diaphragm? The engine only has about 200 hours on it, but I don't know how old the actual servo is.
 
bjohnson1234 said:
After double-checking the intake and looking for any other obvious issues, I did a high-speed taxi which ended up turning into a takeoff. The engine ran smooth for a while, but at one point felt like it was losing power on the climb. Anyone have any ideas of what the problem might be? Anyone around DVT that could help me out with it? Thanks.
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You should ground the aircraft and find someone qualified to help you sort this out before you become a statistic :eek:
 
I would check to see of your cleaning left gunk partially clogging the pressure sensing port in the venturi area.
 
BobTurner said:
I would check to see of your cleaning left gunk partially clogging the pressure sensing port in the venturi area.
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I was initially leaning towards an issue with the injection servo and there could be more than one thing going on here so it's still something worth checking, but that wouldn't cause the low fuel pressure reading. I'm going to dump my engine data into savvy analysis tomorrow and see if there is any useful information there.
 
bjohnson1234 said:
What is the best way to test that?
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First, I would agree that you should not become a statistic, so be sure you have a solution, and don't fly to find out.

Second. For the condition of suction leakage, I am pressurizing the pieces of the fuel system as I go. I am plugging both one end with a pressure gage, adding a valve on the other, pressurizing with air to 35 psi and shutting the valve, The volume of the system is small so a leak gets a pressure drop pretty steady. My plan, as a maximum, is from the tank line, to the servo (post mechanical pump). The best leak detector is Fantastic or 409, but be sure to use it where it can be washed off as it will not play nice with aluminum. If you choose to do this, I would purge the fuel first as it will be a lot easier to detect air leakage.

Others can advise you on good ways to ensure heat is not added to the fuel lines.

BTW - Lycoming has a -2 psi limit at the inlet of the mechanical pump. I would prefer a temp and pressure, but that is all they say.

Good luck and don't be rolling the dice.
 
I fly with a guy that had the some problem, the engine quit on take off. Unfortunately the plane became a total loss when it came back down, fortunately he only got some minor injuries.. It was the servo. The IO-360 was overhauled but the servo turned out to have had it's prior service more then 20 years ago. We sent it to Airflow Performance were every single part in it was AD'ed or rotten. They work great when cared for but will fail if neglected, they can kill you. Get it checked!!!!
 
Ok, I have a little more information after uploading my engine data. Fuel pressure was stable at the time the engine quit. All previous flights including the one post-maintenance showed stable fuel pressure with and without the electric pump. Fuel pressure was also stable on my test flight and any power loss appears to be my overactive imagination as the data shows that everything was stable. After landing and turning off the electric pump the fuel pressure was very erratic.
 
This morning I used throttle body cleaner to make sure no gunk was left inside the servo from my previous cleaning and also checked the filter inside the servo. On the ground I was unable to replicate either the fuel pressure drop, the hesitation on throttle change or the engine quitting when going to idle from full throttle on either tank. OAT yesterday was about 41C and this morning it's 35C. My post-maintenance flight a week ago when everything checked out OK was also about 41C.
 
Engine Issues After Washing

I had a similar issue after washing my O360. Found that the air box had a significant amount of water that had accumulated even though I was careful not to spray directly into the intake. On takeoff roll the engine stumbled and I aborted. Taxied back to hanger, pulled the cowl off and noticed small drip at back of airbox. Drilled a 1/8 hole at the lowest point and outside of the filter area and half a cup of water drained out. After allowing the drip to stop I ran it up on the ground and no issues. Take off and flight around the pattern was uneventful Now when I wash the plane I stuff a bright orange foam Nurff ball into the intake.

Hope you find the problem.
 
X21RV6A said:
I had a similar issue after washing my O360. Found that the air box had a significant amount of water that had accumulated even though I was careful not to spray directly into the intake. On takeoff roll the engine stumbled and I aborted. Taxied back to hanger, pulled the cowl off and noticed small drip at back of airbox. Drilled a 1/8 hole at the lowest point and outside of the filter area and half a cup of water drained out. After allowing the drip to stop I ran it up on the ground and no issues. Take off and flight around the pattern was uneventful Now when I wash the plane I stuff a bright orange foam Nurff ball into the intake.

Hope you find the problem.
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This was my first flight after just washing the plane and there was liquid and "gunk" in the air box when I took it off. I'm not sure if it was water and/or fuel. I also drilled a hole in the bottom to make sure no more liquid accumulated. Sucking up water on full throttle would certainly explain the engine quitting and I'm unable to replicate any issue at all after cleaning the throttle body a second time. I'm still concerned about the low fuel pressure, but so far unable to replicate that either.
 
I've had a ongoing issue with fuel boiling at idle on hot days causing "hiccups" at idle. I wonder if the fuel pressure drop could have been from running it up repeatedly on the ground on a very hot day trying to diagnose the engine failure? I had my plane out at Don's shop about a year ago to look at that issue and he made a few small tweaks to make it better.
 
Carb cleaner

What do you think carb cleaner would in a fuel injection servo. If fuel is the lubricant then carb cleaner may break down the seals as it is a drying agent. For what it's worth
 
As it turns out carb cleaner is not ideal, but also probably not harmful in most circumstances from my research. It is designed to clean off a different mix of contaminants and it is designed to dry more quickly, but most of the ingredients are the same. There are some auto throttle bodies that can be damaged by carb cleaner because they have a special coating, but apparently that is pretty rare. When I cleaned it the second time I used throttle body cleaner that is designed for fuel injected engines.

denbobp said:
What do you think carb cleaner would in a fuel injection servo. If fuel is the lubricant then carb cleaner may break down the seals as it is a drying agent. For what it's worth
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After spending most of the day at the hangar I have come to the following conclusions:

1. The low fuel pressure is most likely not related to the engine stopping. Engine data shows the fuel pressure was normal during the taxi, runup and aborted takeoff. The erratic fuel pressure readings didn't start until I was troubleshooting on the ramp. I think they are most likely the result of the heat of the engine, a 100+ degree day and running on the ramp for extended periods. The electric pump restored normal pressure and I didn't see the problem during any of my tests today.

2. There may or may not be an issue with the servo. I missed a valuable troubleshooting step by cleaning the throttle body a second time before running the engine again, but I have not been unable to replicate any of the problems on the ground that I had yesterday.

3. The most likely cause of the engine stopping was water in the air box from washing the plane. There was a small pool of liquid in the air box when I removed it, but I'm not sure if it was fuel, water or a mix of both. My guess it that it was water because the fuel would probably have evaporated in that time. I have since drilled a small hole in the airbox to prevent anything from pooling in it again.

So, I'm left unsure if there is an issue with the servo. The engine runs perfectly on the ground now and I went through some of the troubleshooting steps, but didn't have the equipment to do others. I think my best bet is to call Don tomorrow and get his input and potentially have someone else do some testing of the servo.
 
In his post he says "I have since drilled a small hole in the airbox to prevent anything from pooling in it again"
 
bjohnson1234 said:
After spending most of the day at the hangar I have come to the following conclusions:

1. The low fuel pressure is most likely not related to the engine stopping. Engine data shows the fuel pressure was normal during the taxi, runup and aborted takeoff. The erratic fuel pressure readings didn't start until I was troubleshooting on the ramp. I think they are most likely the result of the heat of the engine, a 100+ degree day and running on the ramp for extended periods. The electric pump restored normal pressure and I didn't see the problem during any of my tests today.
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Where in the fuel system are you measuring the fuel pressure?
 
I'm also planning on making some changes to the fuel line routing. The installation is non-standard and has a lot of potential to pick up heat.
 
bjohnson1234 said:
The output from the mechanical fuel pump splits and one line goes to the fuel pressure sensor and the other to the servo.
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The typical poor running at idle power with hot engine on the ground is caused by fuel boiling in the injection lines from the spider to the injectors at each cylinder. But, that has no effect on the fuel pressure between mechanical pump and servo. If you saw low pressure there during your testing, perhaps the fuel pump got hot enough to cause the fuel to start to boil there. The fact that turning the boost pump on caused the engine to run better fits this theory.

Do you have fire sleeve on the fuel lines from firewall to servo? It helps to avoid fuel boiling in those lines, plus provide additional safety in the event of a fire ahead of the firewall.
 
Kevin Horton said:
The typical poor running at idle power with hot engine on the ground is caused by fuel boiling in the injection lines from the spider to the injectors at each cylinder. But, that has no effect on the fuel pressure between mechanical pump and servo. If you saw low pressure there during your testing, perhaps the fuel pump got hot enough to cause the fuel to start to boil there. The fact that turning the boost pump on caused the engine to run better fits this theory.

Do you have fire sleeve on the fuel lines from firewall to servo? It helps to avoid fuel boiling in those lines, plus provide additional safety in the event of a fire ahead of the firewall.
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Yea, that's basically what I was thinking. Fuel boiling in either the gascolator or the fuel pump itself. There is fire sleeve on all the FWF fuel lines. I have a blast tube going to the gascolator, but nothing to the fuel pump. It might get some air from the blast tubes for the LASAR control box.
 
Trivia... in Canada, it is so cold... your hand cramps up and O's become U's.
Just can't get over the top. Even their loops in RV's are ovals...
 
Oh, one other thing I did was use K&N filter grease to create a better seal between the filter and the airbox to keep any water out
 
Humm, I've never seen a FI plane without a gascolator. It's imperative you keep any contaminants out of the injection system.
 
FasGlas said:
Humm, I've never seen a FI plane without a gascolator. It's imperative you keep any contaminants out of the injection system.
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My understanding (which might be incorrect) is that the gascolator is not effective at trapping water in an FI engine because the higher fuel pressures will just push it through. There are other filters for contaminants in the system. I have had several very knowledgable people, including Don at Airflow Performance, tell me that I should remove it.
 
Recommended to remove the gascolator...but you still need a fuel filter (or two), usually located before the fuel line penetrates the firewall. This is done to minimize heat absorption.
 
bjohnson1234 said:
My understanding (which might be incorrect) is that the gascolator is not effective at trapping water in an FI engine because the higher fuel pressures will just push it through. There are other filters for contaminants in the system. I have had several very knowledgable people, including Don at Airflow Performance, tell me that I should remove it.
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The gascolator is the pre-filter, water separator and particle trap before the finger screen in the servo. If you sump the gascolator prior to start up any water and contaminants will be removed ( in theory). There is no pressure in a gascolator, just flow. I'm an A&P and I've never seen any FI engine not have a gascolator. They are in every plane we build. I can't see any reason not to have one. But they certainly aren't required in a home built. I've never seen one fail and I would much rather clean a gascolator then the servo screen and injectors.
 
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FasGlas said:
The gascolator is the pre-filter, water separator and particle trap before the finger screen in the servo. If you sump the gascolator prior to start up any water and contaminants will be removed ( in theory). There is no pressure in a gascolator, just flow. I'm an A&P and I've never seen any FI engine not have a gascolator. They are in every plane we build. I can't see any reason not to have one. But they certainly aren't required in a home built.
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The fuel tank drains are the lowest part of the system for collecting water prior to startup. The reason not to have a gascolator is that it transfers heat to the fuel. There is another filter prior to firewall penetration, it just doesn't have a drain for collecting water.
 
gascolator

Never saw a gascolator on McDonnell Douglas, Boeing or airbus.
 
FasGlas said:
Humm, I've never seen a FI plane without a gascolator. It's imperative you keep any contaminants out of the injection system.
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The last 3 airplanes I've owned were fuel injected - and not a one had a gascolator. All had filters, however.
 
Each to their own. It's not required in home built's, nor is any other parts we install for safety or convenience. But we do for safety and convenience.
 
FasGlas said:
Each to their own. It's not required in home built's, nor is any other parts we install for safety or convenience. But we do for safely and convenience.
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In my case, the gascolator is making the plane less safe. By transferring heat to the fuel it's increasing the chance of vapor lock while not providing much of any real benefit beyond the fuel filter at the electric pump. There are several things I could do:

1. Nothing
2. Remove the gascolator
3. Add a cooling shroud to the gascolator and connect the blast tube to it
4. Remove the gascolator and add a second pre-firewall fuel filter

So, what kinds of failures would necessitate a 2nd fuel filter (3rd actually because there is on at the servo)?
 
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Walt said:
Gascolators IMO are a hazard on an RV due to the high under cowl temps creating an ideal environment for vapor lock, in addition, they are not rated for the pressure of a FI system.

Note the "Note" on ACS website:
http://www.aircraftspruce.com/catalog/appages/acsgascolator.php
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Unless you're mounting a gascolator after the fuel pump where is no pressure, it's flow. If anything it would be a vacuum, if the tank got plugged.

Has anyone here ever measured the cowl temps at the firewall? I have and do every flight. I live in SoCal, very hot, the temps never hit 150F at the top cowl, the hottest point. I have a much tighter cowl then an RV.

These discussion always remind me of an old auto radio show I was listening to maybe 25 years ago. They had a guy from GM on there taking questions. It was just a matter of time before the holy grail of engine topics was asked. " I want to remove my radiator thermostat because everyone tells me my engine will run better if I do ". After a few seconds the guy from GM said " I get this question asked of me more times than I can remember ", " the answer is, If the engine didn't need it no car maker would waste the money to install it ". I will never forget that answer.

All I can say about the use of gascolators is my own experience. Every experimental I've been involved with, from Reno racers to OSH grand champion winners, and everywhere in-between, has a gascolator. Not one has ever failed, leaked or burst. Not one has gotten vapor lock from a gascolator. It's far more likely a fuel line next to a 400F cylinder would get vapor lock then the fuel in a gascolator at the bottom of a firewall.. Heat rises. But again, each to their own.
 
FasGlas said:
All I can say about the use of gascolators is my own experience. Every experimental I've been involved with, from Reno racers to OSH grand champion winners, and everywhere in-between, has a gascolator.
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I would hazard a guess that you have not been involved with too many F/I RV's in that case.

Add my plane to the long list of gascolator free F/I RVs.
 
FasGlas said:
Unless you're mounting a gascolator after the fuel pump where is no pressure, it's flow. If anything it would be a vacuum, if the tank got plugged.

Has anyone here ever measured the cowl temps at the firewall? I have and do every flight. I live in SoCal, very hot, the temps never hit 150F at the top cowl, the hottest point. I have a much tighter cowl then an RV.

These discussion always remind me of an old auto radio show I was listening to maybe 25 years ago. They had a guy from GM on there taking questions. It was just a matter of time before the holy grail of engine topics was asked. " I want to remove my radiator thermostat because everyone tells me my engine will run better if I do ". After a few seconds the guy from GM said " I get this question asked of me more times than I can remember ", " the answer is, If the engine didn't need it no car maker would waste the money to install it ". I will never forget that answer.

All I can say about the use of gascolators is my own experience. Every experimental I've been involved with, from Reno racers to OSH grand champion winners, and everywhere in-between, has a gascolator. Not one has ever failed, leaked or burst. Not one has gotten vapor lock from a gascolator. It's far more likely a fuel line next to a 400F cylinder would get vapor lock then the fuel in a gascolator at the bottom of a firewall.. Heat rises. But again, each to their own.
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If you are blindfolded standing in a wind tunnel, you can't tell the difference between a fan in front of you "pulling" and one behind you "pushing". There is still "pressure" going through the gascolator even though mechanical fuel pump is pulling the fuel through instead of pushing it. Also, the electric fuel pump is pushing it through.
 
FasGlas said:
Unless you're mounting a gascolator after the fuel pump where is no pressure, it's flow. If anything it would be a vacuum, if the tank got plugged.

Has anyone here ever measured the cowl temps at the firewall? I have and do every flight. I live in SoCal, very hot, the temps never hit 150F at the top cowl, the hottest point. I have a much tighter cowl then an RV.

These discussion always remind me of an old auto radio show I was listening to maybe 25 years ago. They had a guy from GM on there taking questions. It was just a matter of time before the holy grail of engine topics was asked. " I want to remove my radiator thermostat because everyone tells me my engine will run better if I do ". After a few seconds the guy from GM said " I get this question asked of me more times than I can remember ", " the answer is, If the engine didn't need it no car maker would waste the money to install it ". I will never forget that answer.

All I can say about the use of gascolators is my own experience. Every experimental I've been involved with, from Reno racers to OSH grand champion winners, and everywhere in-between, has a gascolator. Not one has ever failed, leaked or burst. Not one has gotten vapor lock from a gascolator. It's far more likely a fuel line next to a 400F cylinder would get vapor lock then the fuel in a gascolator at the bottom of a firewall.. Heat rises. But again, each to their own.
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Here in Phoenix the ambient temps are 110. The difference between the gascolator and the fuel line is that the gascolator is a good conductor of heat and a firesleeve wrapped fuel line is not. Interestingly enough, the fuel line to my spider doesn't run between the cylinders, it comes up from behind the engine and goes through the baffle. Just because in your personal experience no one has gotten vapor lock doesn't mean that it doesn't happen. The original suggestion to remove the gascolator came from Don at Airflow Performance and I think you'd be hard pressed to find anyone here who doesn't think he's an expert on the topic. Since I bought my plane it's had an issue with fuel boiling in the lines causing small hiccups at low rpm when the plane is hot. Other people with the same problem have fixed it by removing the gascolator. There is little doubt it contributes to the problem and it's very likely that my non-standard fuel routing is causing a problem, the only question is the seriousness of it. Did my plane vapor lock on the runway or did it suck up water? Probably the later, but I don't know for sure.
 
Mike, I do fly with some RV's, as you know, and we work on some as well. I can't recall any RV Reno racers.... We all use the same components for the most part and as I stated these are my experiences with many FI Lycoming powered aircraft. Maybe it's the build and not the parts. I can't say.

bjohnson, Pressure is not the same as flow! If you have your fuel tank wide open to you filter and the pump is pulling the fuel through it it is not pressure, it's flow. There is constant pressure and there is constant flow. A Harley Davidson engine runs on only a few PSI of oil pressure but flows a gallon a minute of oil over the bearings and cylinders, put a gauge on the pump port and read 5 PSI.
 
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