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High EGT on left side

S

sdixon

I'm New Here
Hello can anybody give me a proper help with this problem.

Carburetors are balanced mechanically and pneumatically. This has been double checked. My EGT on the left side reads 80 to 100 degrees higher than the right side. It's just high enough to set off into the yellow zone at 1475

Steve d.
 
You mentioned the carbs have been balanced... does it run really smooth?

If it is a newly completed airplane, you should probably look carefully at the carb, and manifold installation (removed during installation of the cyl cooling shroud) on the hot EGT side, for possible induction leaks.
 
Steve,
Are the EGT temperatures the same when the engine is cold and also when idling?
Put a hairdryer on the suspect probe and watch the display to verify that the left are right sides are not interchanged. That has been a problem for some builders.
Joe Gores
 
Mine runs about 1270F on the hottest. There is an 80-90F difference between left and right, but I can't remember which runs hotter. Your temp seems hi to me, but I only have my engine to compare it to.
 
temps

Hi try heating the sensors with a heat gun and confirm that they are in the correct exhaust the fronts will run considerably cooler than the rears because of the colder air and also try heating each on for the same amount of time and see if they reach a similar temp this will rule out wiring faults etc crossed polarity on thermocouples can give strange results
once you have proved the sensors are reading correctly it is time to start looking for manifold leaks etc
 
Confirm: probe or engine

To expand just a bit on what Joe says... Swap the EGT connections up at the top of the engine and see if the problem moves to the other line on the Dynon. If so, it's the probe.

While you have the connectors off, apply some dielectric and firmly re-install. This will prevent the intermittent EGT spikes some of us have seen.

Any significant difference in plug color right to left side?

Jim
#264 flying 165 hours
 
Last edited:
Switched over the pair of egt leads. Problem traveled to right side. Now I'm checking for induction leaks and replacing probe
 
mixture on the bottom

sdixon said:
Does anyone know how to make that carb run just tad richer. Is there a mixture screw for that
Click to expand...

The mixture control is on the bottom of the carb, and, because of the drip pan, impossible to adjust without pulling the carb off its rubber shock mount.
 
I don't claim to be an expert, but when I went to the CPS Rotax course they said this (the adjustment on the bottom of the carb) is a factory setting that shouldn't be messed with.
 
sdixon said:
Switched over the pair of egt leads. Problem traveled to right side. Now I'm checking for induction leaks and replacing probe
Click to expand...

I'm not the sharpest tool in the shed, but if the high temp traveled with the leads being switched it is not a problem with the engine, it is a problem with the probe. :confused:
 
egt

Dont touch the mixture screws the problem is with your sensor or probes
if the problem can be swapped from one side to the other by swapping the probes the problem is with the wiring not the engine
check the wire colors all the way to the monitor you will find there is a swap somewhere
 
If the problem moved to the other line on the Dynon EGT display, it is the probe or (somehow) its installation. Call Dynon or take your chances getting an answer on the Dynon Forum. In my experience the techs have been very helpful.

If the fix is a new probe you can consider yourself lucky as many of us have dealt with more time-consuming and costly glitches with the Rotax-Dynon interface.

Jim
 
sdixon determined that one of the EGT probes is sending out a signal that is about 90 degrees hotter than the other probe. Is the probe lying or telling the truth? The only way to find out is to replace the probe or swap it with the one on the other side.
But why bother? I would raise the EGT alarm setpoint or disable it after reading the article below by Mike Busch who is an expert on aircraft engines. His articles have appeared in Sport Aviation.

Joe Gores

https://www.savvyanalysis.com/articles/egt-myths-debunked
Mike Busch said,
Even if indicated EGT accurately reported actual exhaust gas temperature (which it doesn't), it's important to understand that exhaust gas temperature does not correlate with stress on the engine . . . . .Absolute values of EGT (e.g., 1475°F) are simply not meaningful and are best ignored. There is no such thing as a maximum EGT limit or red-line, and trying to keep absolute EGTs below some particular value - or even worse, leaning to a particular absolute EGT value - is simply wrongheaded. Don't do it. If you must fixate on those digital engine monitor readouts, fixate on something important like CHT.
Click to expand...
 
Last edited:
The chat is just fine. Swithcing probes this week........btw. If you pull the choke out 1/8 inch it cools down everything whichnisnwhy I don't underrstand why it is not proper to balance the richness based off of egt values. The mechanical balance. The pneumatic balance and then the richness balance.........any takers on that?
 
confused

RFSchaller said:
I don't claim to be an expert, but when I went to the CPS Rotax course they said this (the adjustment on the bottom of the carb) is a factory setting that shouldn't be messed with.
Click to expand...

Hi when you said you switched over the leads did you swap them from the left side of the engine to the right side or did you reverse the polarity of the leads on one side if you switched the leads from the left sensor to the right sensor and the high temp moved to the other side the problem must be with the wiring

and when you pulled the choke out did both temps drop or only one side
and the reason for not adjusting the mixture is that the rotax manual specificaly states that they factory set and must not be adjusted

running with the choke out will make it run coooler but also very rich and will use heaps of fuel
 
crashley said:
running with the choke out will make it run coooler but also very rich and will use heaps of fuel
Click to expand...

This is correct - it can also lead to unburned fuel in the cylinders which washes off the lubricant and can lead to rapid bore wear. A good reason to get the engine off the choke as quickly as possible.
 
if you switched the leads from the left sensor to the right sensor and the high temp moved to the other side the problem must be with the wiring
Click to expand...
It all depends on where the wires are switched, EFIS end, middle, or probe end. There is a convenient splice in the middle at the firewall. If the wires are switched close to the probes, then the wire from that point to the EFIS has not changed. Wire that was connected to the left side of the EFIS is still connected to the left side of the EFIS.
Joe Gores
 
high egt on left side

I have the same problem as the first person has, I switch the probes
and the problem stayed with the left side. The left side is always
higher than the right side. When at full throtle both are the same.
 
The rear left cylinder had the worst air cooling advantage in the rv12. That's what I'm thinking. Anybody else have left side higher temps. Also my cht is the same on both sides within normal limits
 
sdixon said:
The rear left cylinder had the worst air cooling advantage in the rv12. That's what I'm thinking. Anybody else have left side higher temps. Also my cht is the same on both sides within normal limits
Click to expand...

Cyl cooling will have very little effect on EGT readings.
Didn't you already say that you swapped the EGT probe connections and the high reading switched to the other cyl? If so, then it is an indication problem, not something specific to the engine
 
Is this a Skyview installation?

If so, you can reprogram the EMS indications in about two minutes without ever touching a wire.

Bob Bogash
N737G
 
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