I was in bonanza (only 300 hours on the engine) yesterday in IMC, and the engine started running a little rough. After a while, the roughness turned into a jolting miss. The engine was missing and it was becoming more frequent as the flight went on. I Lean the airplane for 25 rich of peak in every phase of flight, so i don't think i fouled it by running it too rich. Has anyone has problems with their engine missing before? any ideas? Maybe it's not even a miss. Maybe it's detonation or something.
Engine trouble
- Thread starter jikky54
- Start date
esa17
Well-Known Member
What type of fuel containment does the Bo have? Some bladder wing tanks are certified to hold an obscene amount of water which recently caused a friend of mine to put his down in a soy bean field.
What type of engine instrumentation does the plane have? Could you tell if any of your temps were askew from normal?
How did it change in relation to your altitude? I.E. Better when lower...
What type of engine instrumentation does the plane have? Could you tell if any of your temps were askew from normal?
How did it change in relation to your altitude? I.E. Better when lower...
I have an EGT, fuel flow, CHT, and Oil temp. Cylinder and oil temps looked fine, but im starting to wonder if the EGT is not calibrated. It peaks at about 1325 and i run it at 1300 and the fuel flow looks normal at these temps. I think the engine book says it's supposed to run a little higher. The miss, if that's what it was, didn't seem to get any better or worse with altitude, mixture, prop setting, or manifold pressure setting. I had to shoot an ILS down to 500 at addison with the engine running like this and i had no idea what the problem was. I don't know what kind of fuel containment it has, but i sumped the out of the fuel. I probably dumped a gallon out, just to be safe because it got rained on. I got a really good fuel sample before i took off. No contaminants and no water.
Inverted25
Well-Known Member
did you try isolating it by trying running on the left or right mag only to see if it was a mag problem
jhugz
Well-Known Member
:yeahthat:
Make sure when you do this if the engine dies you let it. Don't immediately go back to both and blow up your exhaust.
Douglas
Old School KSUX
Single probe or a six probe EGT/CHT gauge?
What % power were you running?
Did you do a mag check after landing?
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Thing to try next time-
You didn't mention it, did you switch tanks?
Try turning the fuel pump on, but don't leave it on. It could kill your engine. Adjust mixture with fuel pump on.
Check your mags - if you have a bad mag, run on the good mag and en-richen the mixture because you will be running hotter on one.
It's says Lubbock, but you were IMC and could try ALT air.
Other than that, that is about all you can do from the cockpit.
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Do you own John C Eckalbars book "Flying the Beech Bonanza"?
It is really a must read for anybody who often finds them-self inside a beautiful bonanza.
What % power were you running?
Did you do a mag check after landing?
------
Thing to try next time-
You didn't mention it, did you switch tanks?
Try turning the fuel pump on, but don't leave it on. It could kill your engine. Adjust mixture with fuel pump on.
Check your mags - if you have a bad mag, run on the good mag and en-richen the mixture because you will be running hotter on one.
It's says Lubbock, but you were IMC and could try ALT air.
Other than that, that is about all you can do from the cockpit.
------
Do you own John C Eckalbars book "Flying the Beech Bonanza"?
It is really a must read for anybody who often finds them-self inside a beautiful bonanza.
Douglas
Old School KSUX
True, you could get a back fire, but it would be easier to retard the throttle.
It's a six probe EGT and the hottest cylinder wasn't much hotter than the others, maybe 100 degrees. I got a good mag drop before i took off and after. I did notice that the engine backfired on startup and it never does that. The hottest cylinder was no. 2. I did, however, neglect to try one mag at a time in the air.
trafficinsight
Well-Known Member
kinda sounds like a sticking valve to me, but based on the information given it could be a lot of things.
es-splain me please.
We are neck and neck!!! I am gonna win...
PS Explain this to me too I don't get it.
BrewMaster
Well-Known Member
If the engine dies, let it die, otherwise you will ignite all the unburned fuel in the exhaust pipes. It sounds like a backfire and could literally blow out your exhaust. I had a student do this to me once. She had pretty twitchy hands to begin with and went to far when checking the right mag. Always warn your students about this, not so good on engines or exhaust systems.
I don't think I would be too comfortable with trying to isolate a mag in imc. I would try everything I could think of first, isolating a mag would probably be my last choice.
I don't think I would be too comfortable with trying to isolate a mag in imc. I would try everything I could think of first, isolating a mag would probably be my last choice.
Mag check, yes. Failing engine, not likely. If it won't ignite in the combustion chmaber, it's probably no going to ignite in the exhaust system either. There has to be a fairly close ratio of uncontaminated air/fuel for proper ignition. Otherwise it will just burn like a puddle of fuel. And if it's dying, there probably isn't the correct ratio.
Engine quiting to me sound like me trying to fix it before it get s to the point of quitting completely. Even if it is running rough.
To the OP. Depending on what engine you have in the bonanza, I'd get a compression test done at the very least. With it still running, all be it rough, it could be a number of things. Pluged injector, cracked head, broken ring, burnt valve, sticking valve, etc. A compression check would eliminate a cyl. problem right off the bat. But takeing it to a mechanic, that's probably the first thing he would recomend anyways. It a direct indication of the health of the cyl's.
Engine quiting to me sound like me trying to fix it before it get s to the point of quitting completely. Even if it is running rough.
To the OP. Depending on what engine you have in the bonanza, I'd get a compression test done at the very least. With it still running, all be it rough, it could be a number of things. Pluged injector, cracked head, broken ring, burnt valve, sticking valve, etc. A compression check would eliminate a cyl. problem right off the bat. But takeing it to a mechanic, that's probably the first thing he would recomend anyways. It a direct indication of the health of the cyl's.
BrewMaster
Well-Known Member
Considering none of us have any idea what is wrong, I'm not gonna "hope" it doesn't blow out my exhaust in imc. The point was if it's gonna die, let it die, trying to restart probably won't work anyways and if it does, there is a chance it could blow out your exhaust and you just broke your engine that was gonna come back to life. If it the engine wasn't going to restart then there is no point. The point being is that there is no reason to try to restart, let it die and then try it. There is a small chance of this happening, but it's not worth it, what you would gain is very little and what you could lose is a lot.
jhugz
Well-Known Member
Try it on a runup (low descent power setting) and then tell me what happens. Now imagine it at a cruise power setting. You will blow up your exhaust.
The airplane will continue to run again once you introduce the spark. If you check the mags in the air and the engine dies let it. Then pull your power all the way back to idle and re-introduce the spark. The engine will come back fine w/ out blowing up the exhaust.
BrewMaster
Well-Known Member
Yep, I was just illustrating what happens if you just leave the throttle in and reintroduce the spark.
An engine will run if you remove the exhaust completely. I'd rather have to spend money on exhaust than a funeral.
I know what happens when there is a burnable cocktail in the exhaust. It's never good. But I spent more than a few years makeing a living diagnosing/repairing engines. 9 to be exact. If it won't burn in the engine, it simply wont burn anywhere. When you increase the pressure of the fuel in a cyl., it will burn much more eaisly than it will in an open enviroment like an exhaust system. And the spark/heat is already there to light off whatever is already in the exhaust system from the other cyl's. You have to completely eliminate a source of ignition and then re-introduce it to get the bang we all know when you, "oops," go to far with a mag check. They are two completely different scenarios. You should never let the engine die, and then try to re-start, if it can be avioded. What if the needle sticks, and the float bowl wil not re-fill(carb talk)? What if it continues to run rough for 15 mins., all the way down to the ground. Fix it NOW, not when it finally decides to quit. The fuel from the other cyls. is still on fire when it leaves the cyl, thats why the unburnt fuel get's ignited in the 'oops' situation. And the engine is stil running, so you will not get the pop from the mixture in the exhaust.
FWIW Jhugz, the reason why you don't get the bang when checking during a pre-shut down mag check vs. a run up, went to far with the key mag check is has nothing to do with the power setting. But it has everything to do with how much fuel is present. Take an airplane up to altitude, pull it back to idle with an excessively rich mixture, and listen to it pop and backfire. The reason it's happening is because unburnt fuel is makeing it's way into the exhaust, and being ignited as it exits. The other scenario you speak of is because at a highr power seting, with more air velocity going through the engine, the fuel is in more of a vapor state (properly atomized) and will more redialy burn because of a closer air-fuel raio to optimum. And due to that, it will ignite while still in the exhaust, not while exiting.
I'm hungry, I gotta get some lunch.
MidlifeFlyer
Well-Known Member
What were the temperatures outside? Any chance of induction air icing?
deadstick
Well-Known Member
With a 6 pt EGT, your indicator would tell you which cylinder was having a problem regardless of the cause (fuel, air or fire). If it's a JPI, can you download the data?
As for the boost pump, you can put it on low to purge any vapors from the line. Does it have the altitude-compensating fuel pump?
As for the boost pump, you can put it on low to purge any vapors from the line. Does it have the altitude-compensating fuel pump?
XLR99
Well-Known Member
I'm wondering if there's a correlation to running 25ROP - that seems very hot to me. Most of the reading I've done lately points to running further ROP like 100-150, or LOP (assuming IO-XXX with decent injectors and 6pt EGT/CHTs).
I used to have a ppt from an engine management seminar that talks about the Red Fin area, plotting intra-cylinder temps and pressures at various mixture settings. At a range around peak there is the highest probability of doing badness to the engine.
Which engine, what power settings were you running, etc?
I used to have a ppt from an engine management seminar that talks about the Red Fin area, plotting intra-cylinder temps and pressures at various mixture settings. At a range around peak there is the highest probability of doing badness to the engine.
Which engine, what power settings were you running, etc?