Engine Monitor on Carbureted Engine

[Jaybird180]

The Skylane that I'm considering has a JPI EDM-700 installed on an O-470U engine. The seller says that he has been flying it LOP and represents it as a good strong engine.

I like FI engines and would consider converting at OH time, which is likely in 2-8yrs. I'm budgeting for the OH, of course.

Is there any real value in having the JPI on the carbureted engine? FWIW, there is a separate carb inlet temp gauge for forewarning of carb ice plus there is a Shadin totalizer installed also (I would have fed the data into the JPI, but hey).

What are the viable options (short of a P-Ponk) for just converting the engine to FI? My rationale is to eliminate icing potential, reclaiming panel space and also thinking I could run the engine truly LOP for a MPG savings.

 

[Stewartb]

I have an EDM711 primary replacement in my 180 w/ 0-520. I use it to control CHTs virtually every flight. EGTs don't concern me but they would a LOP guy. I have a separate FS450 fuel monitor. Didn't want it added to the EDM. My EDM does have a carb temp probe so I can view that if I want but I never do. My engine doesn't make ice. I can lean my engine for 16gph at 24/2400 and my temps are so flat it's amazing. It's taken a lot of effort and time to get it there, too.

As for FI? Lots of 0-470s and 0-520s in Alaska have Bendix FI installed by field approval. How efficiently it works for LOP? No idea. Bendix FI, unlike TCM's, doesn't require a fuel return line or a header tank. That's why it's the popular choice for adding FI to a carbed airplane.

 

[GeorgeC]

Is there any real value in having the JPI on the carbureted engine? FWIW, there is a separate carb inlet temp gauge for forewarning of carb ice plus there is a Shadin totalizer installed also (I would have fed the data into the JPI, but hey).

I use the JPI for CHT management and fuel flow, and the lean assist mode is helpful even for non-LOP ops.

 

[MAKG1]

An engine monitor also makes some run-up problems considerably more obvious. Doesn't matter if it's carbureted.

 

[PilotRPI]

I have one on my O-300. Leaned out and cruising, I keep my carb at least 40 degrees, sometimes with a touch of carb heat in colder temps, and the CHTs are dead even. If one of them started to fluctuate, it could indicate to me there could be an issue. I like the carb temp readout for the O-300, as it can have icing issues even at cruise power under the right conditions.

 

[bnt83]

The Skylane that I'm considering has a JPI EDM-700 installed on an O-470U engine. The seller says that he has been flying it LOP and represents it as a good strong engine.

I like FI engines and would consider converting at OH time, which is likely in 2-8yrs. I'm budgeting for the OH, of course.

Is there any real value in having the JPI on the carbureted engine? FWIW, there is a separate carb inlet temp gauge for forewarning of carb ice plus there is a Shadin totalizer installed also (I would have fed the data into the JPI, but hey).

What are the viable options (short of a P-Ponk) for just converting the engine to FI? My rationale is to eliminate icing potential, reclaiming panel space and also thinking I could run the engine truly LOP for a MPG savings.

I have a story about my little O320 with a 4 cylinder engine monitor. My O320 is very old in years and still not quite to 1600 hours total time. It seems to use a bit of oil etc.

I was getting ready to leave for a 200 NM trip and everything seemed to be going well, taxied out letting the engine warm up before the mag check.

Mag drop check was bad! Its never happed to me between annuals in 5 years with new plugs and new mags. I did everything I could think of to trying to clear the plug that was shorted out with no luck.

I noted that the EGT was falling off on cylinder #3 with the ignition switch in the "L" position.

From there I taxied back to the hangar and had the cowl off in 5 minutes. I traced the #3 cylinder spark plug wires back to their mags and the lower plug was fired by the left mag. I pulled that plug and found it full of crap, cleaned it, reinstalled and had the cowl back on in about 15 minutes from the time the problem was discovered to taxing back out for departure.

That day, I was pretty happy I had an engine monitor. Most other days it just helps me get the most out of the engine without hurting it, she gets hot sometimes! Its weird because the hottest cylinder changes depending on configuration. I think #4 is hottest in the climb but moves to a different one during cruise.

 

[James331]

Running LOP is only one benifit of a monitor.

For me the real value is peace of mind, I can see trends before they become real issues, I can diagnose engine issues on the ground, helps for leaning even in a carbed engine.

My trust factor in a plane is quite diffrent if I have a JPI700 or better vs just the FAR bare bones, or a single value CHT gauge.


In the futures in planning on replacing my primary engine and fuel instruments and JPI with a EI all in one, much more accurate and with the GPS input and fuel flow, it really helps with systems management

 

[edo2000]

Great topic. I learned some stuff.