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High #4 EGT

Rollout34

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I'm looking for a little help to figure out why my number 4 EGT is usually 100 degrees hotter that my other EGT's. I have a RV6a with an IO-320 160hp Lycoming engine with an Advanced 5600 10" screen that shows all 4 EGT's and all 4 Cyc head tempts.

I have owned this airplane for 4 months and use it to commute to work. My commute is normally 3.5 hour flight. I usually fly between 8000' and 12000' msl. This is a new problems that just started with the last 2 weeks.

I usually fly lean of peak using Mike Buschs information and I realize he says not to worry about Higher EGT's. However my #4 EGT is much higher than the others. Yes, the cylinder tempt is well within limits at 343 with the EGT being 1458 (in the Red). (#1 330/1365, #2 357/1380, #3 353/1320, #4 343/1458) its certainly annoying since it sets the alarms off on the display screen both visual and audio. The number #4 EGT has recently went above 1500, above the limits on my screen. I was at 11300 msl and an OAT of 40F, on last weeks flight. Yesterday, taking off and flying at 2500 msl I saw almost a 200 degree difference in tempts. #4Cyl head of 339 (good) with an EGT of 1551 super high. The other 3 EGTs were 1376/1393/1331. 3 hours later into the flight at 8500msl an OAT of 52F #1 329/1380, #2 351/1383, #3 350/1328, #4 341/1495.

Can I clean or replace the probe? or is there other trouble shooting that I should look at?

V/R Brent
 
I'm looking for a little help to figure out why my number 4 EGT is usually 100 degrees hotter that my other EGT's. I have a RV6a with an IO-320 160hp Lycoming engine with an Advanced 5600 10" screen that shows all 4 EGT's and all 4 Cyc head tempts.

I have owned this airplane for 4 months and use it to commute to work. My commute is normally 3.5 hour flight. I usually fly between 8000' and 12000' msl. This is a new problems that just started with the last 2 weeks.

I usually fly lean of peak using Mike Buschs information and I realize he says not to worry about Higher EGT's. However my #4 EGT is much higher than the others. Yes, the cylinder tempt is well within limits at 343 with the EGT being 1458 (in the Red). (#1 330/1365, #2 357/1380, #3 353/1320, #4 343/1458) its certainly annoying since it sets the alarms off on the display screen both visual and audio. The number #4 EGT has recently went above 1500, above the limits on my screen. I was at 11300 msl and an OAT of 40F, on last weeks flight. Yesterday, taking off and flying at 2500 msl I saw almost a 200 degree difference in tempts. #4Cyl head of 339 (good) with an EGT of 1551 super high. The other 3 EGTs were 1376/1393/1331. 3 hours later into the flight at 8500msl an OAT of 52F #1 329/1380, #2 351/1383, #3 350/1328, #4 341/1495.

Can I clean or replace the probe? or is there other trouble shooting that I should look at?

V/R Brent
Since you're fuel injected, check for an induction leak (excess air) to that cylinder. Second thing is to check for is a restriction in the fuel line to that cylinder (also would cause a leaner condition to that cylinder). If
those don't pan out then the next culprit would be the EGT probe.
 
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You did not mention what type ignition you have. The higher temp could be a plug dropping out in that cylinder. Do a mag check at altitude and you will eliminate or confirm that possibility. I have had a light speed speed ignition that test fine on the ground but above 6000 feet one side of one coil would drop out.
 
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You did not mention what type ignition you have. The higher temp could be a plug dropping out in that cylinder. Do a mag check at altitude and you will eliminate or confirm that possibility. I have had a light speed speed ignition that test fine one the ground but above 6000 feet one side of one coil would drop out.

+1

MOst likely reason is a plug not sparking. It is not uncommon for a plug to spark at 1800 RPM Rich, but not at 2500 RPM lean and higher MAP. Second would be an issue with the probe itself. If running LOP, an induction leak would result in a lower EGT, not higher.

Larry
 
I just had a similar problem. The EGT on my No. 1 Cylinder would be running along at about 1400 and then drop off the scale, or pop up to 2400! Replaced the probe. it's now running a bit warmer than the other three but will "burn" in a bit I am sure. You could swap probes around but likely it's the simple problem.
 
Clean the #4 injector and see if that cures the problem. I'm guessing it cannot be an induction leak as you are running wide open throttle at that kind of altitude. At WOT the differential between ambient pressure and manifold pressure is very small, meaning any leak is leaking the least it could for any configuration considered.
 
This is not an injector issue. Dont go pulling them out for the risk of creating a problem is greater.

If you are LOP, and its running smooth, its not a partially blocked injector with a higher EGT. If it was it would be lower EGT.

Most likely a spark plug problem.

Do a LOP, in-flight mag check. You will soon see which mag is connected to the faulty plug.

A good mag check will have them all rise and not run rough.
https://www.youtube.com/watch?v=R0RjCgxNvp4

And change your alarm setting. No need for alarms on EGT.
 
Why not just swap probes around between cylinders and see if the problem follows the probe. I am guessing it will. Buy a new probe and install. Done.
 
Ahh I did not catch the LOP, in that case a partially plugged injector would likely be so lean it would just quit running.

Instead of swapping probes why not just swap both plugs to a different cylinder? Probably easier than moving the probes...
 
Before doing anything just do the inflight mag check. Simple and requires no maintenance actions. You will know where to go from there.
G
 
Why not just swap probes around between cylinders and see if the problem follows the probe. I am guessing it will. Buy a new probe and install. Done.
I just swapped EGT probes. I will see if the problem moved to the Number 2 EGT when I do my test flight today. I will also do the inflight mag check that most people suggested as well.
Thank you all, for your responses. Great info and website.
V/R Brent
 
Before doing anything just do the inflight mag check. Simple and requires no maintenance actions. You will know where to go from there.
G
I had the cowlings off for the oil change, so I moved the egt probe to the number 2 position. I also noticed that the #2 probe was really bent, however that one was working good. I will do the inflight mag check as you suggested.
V/R Brent
 
During my test flight, the problem moved to the number 2 EGT. That confirms it was a bad EGT probe. Once I figure out which probes I have I will order a new one. Thank you guys for your input
V/R
Brent
 
I'm looking for a little help to figure out why my number 4 EGT is usually 100 degrees hotter that my other EGT's. I have a RV6a with an IO-320 160hp Lycoming engine with an Advanced 5600 10" screen that shows all 4 EGT's and all 4 Cyc head tempts.

I have owned this airplane for 4 months and use it to commute to work. My commute is normally 3.5 hour flight. I usually fly between 8000' and 12000' msl. This is a new problems that just started with the last 2 weeks.

I usually fly lean of peak using Mike Buschs information and I realize he says not to worry about Higher EGT's. However my #4 EGT is much higher than the others. Yes, the cylinder tempt is well within limits at 343 with the EGT being 1458 (in the Red). (#1 330/1365, #2 357/1380, #3 353/1320, #4 343/1458) its certainly annoying since it sets the alarms off on the display screen both visual and audio. The number #4 EGT has recently went above 1500, above the limits on my screen. I was at 11300 msl and an OAT of 40F, on last weeks flight. Yesterday, taking off and flying at 2500 msl I saw almost a 200 degree difference in tempts. #4Cyl head of 339 (good) with an EGT of 1551 super high. The other 3 EGTs were 1376/1393/1331. 3 hours later into the flight at 8500msl an OAT of 52F #1 329/1380, #2 351/1383, #3 350/1328, #4 341/1495.

Can I clean or replace the probe? or is there other trouble shooting that I should look at?

V/R Brent[/QUOTE

After moving the #4 EGT probe to the number #2 position I noticed the problem is now in the number 2 position. That confirms that the EGT probe was bad. Thank you guys for your input.
V/R
Brent
 
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