HIGH EGT ON ONE CYLENDER

[ChristianGodin]

Hello, 

I have a 201 and the egt/cgt are indicating as follow:

1. 1126.  331

2. 1411   365

3. 1047.  335

4. 1087.  314

Does any one could tell me how I should interpret the high EGT on cylinder no. 2.

Thank You

[WardHolbrook]

Probe issue perhaps?

[jackn]

Quote: WardHolbrook

Probe issue perhaps?

[sreid]

Does it run smooth on each mag individually on the ground and in flight?

[ChristianGodin]

I will check the mags in the air and get back. On the ground it does ron smothly. Indeed EGT and CHT are both higher then the other. I am away from home. Is it safe to fly like this I have two 3 hours leg to do in the next days.

Thank You

 

[danb35]

In-flight mag check is the first thing I'd look at, GAMI spread is the second.

For the in-flight mag check, in cruise flight, run the engine as lean as it will run smoothly, and then run it first on one mag, then the other, for about 30 sec. each.  You should see EGTs rise consistently across all cylinders.

For the GAMI spread, at 65% power or less, lean the engine until the last cylinder to peak is at least 20 degrees F lean of peak EGT, and ideally 50 degrees.  Note the fuel flow at which each cylinder peaks.

Plugged injector is a likely culprit; induction air leak somewhat less so.  How were you running the engine when you got these temp readings?  MP/RPM/fuel flow/altitude?

[ChristianGodin]

I was flying at 7000 feet, and MP was 21 approx., RPM 24 and FF 9.5. Then I raised te FF at 11 and EGT remained pretty much the same. When I started the decent, the airspeed raised and the EGT raised to 1490 for cynlinder no. 2.

[Cruiser]

Are these new readings or something that you have always seen? I.e. is this different than what you normally get?

At 7000' 21x24 9.5FF my IO360 is LOP but the EGT is in the 1430°F range. If you are only getting 1047-1126 for EGT readings the probes are probably further down the exhaust stack. Check that all probes are the same distance or nearly so.

If you went from 9.5 gph to 11 gph without change to EGT there is something wrong with the monitor.

[danb35]

What happened to the CHT when you went to 11 gph?  Did you try going a little leaner instead (say, 8.5 gph)?

[Cris]

 

 

1.Indicato shows: a gradual or sudden rise in EGT of one cylinder. When temperatures are 50°F above normal the display will blink to warn you of the rise in temperature.

 

Probable cause: A) A fouled or defective spark plug or ignition wire. A plug with a cracked insulator may misfire at high altitude but function normally on the ground.

 

What to do: Switching to left and right mags momentarily will determine which plug or lead is at fault. Switching off the good plug will cause the EGT in affected cylinder to drop while all others will rise. A fouled plug may clear itself when mags are switched.

 

Probable cause: A reduction in the fuel supply to one cylinder. A partially plugged injector will cause EGT to rise. A leak in the fuel supply tube between the fuel distributor and injector will have the same effect. A completely plugged injector or fuel supply will result in no combustion.

 

What to do: Switching mags will cause EGTs to rise in all cylinders. There will be no drop in temperature as with the fouled plug.

[garytex]

#2 has the longest intake runner, prone to vibration wear at the upper flange giving induction leaks.  Also the culprit in several loose nut scenarios.  

[jetdriven]

Umm,  the IO-360 all 4 runners are the same length.  This engine was made to run LOP.

 

[ChristianGodin]

I stop by the mecanic shop "Griffen Aviation Service" at the airport of Hyannis, Massachuset. The problem was, indeed, a foule spark plug and the injecter of the same cylinder that was partly block.

Thank You all.

N.B.: These guys at Griffin gave me a very good service.

[garytex]

Jetdriven.  2 may be same length, but it is the least supported, and a frequent source of troubles.  The two or three guys that have had loose intake nuts reported on the forum were on #2.  I got the heads up about #2 runner from Mark at Custom Airmotive, in Tulsa.  He is a well respected engine overhauler, and is a sharp and observant guy.  When my mechanic and I were puzzling over the repeated #2 cyl problems in the logs, and disassembled on the shop floor of my new F, he pointed us to the problem (Intake tube, with fretting on the flange giving intake leaks).  Look at the thing, it also looks like a candidate for vibration.  His other words about #2 were that that is a frequent case cracking location.  Aviation Consumer did a statistical analysis on cylinder SDR's several years ago that came up statistically significant for #2, whether it be the front cyl on a LYC or back on a CONT, #2 led the parade.

Luckily our friend above's troubles were cured elsewhere, but when #2 gives leaner EGT, I think it's worth considering an intake leak.

Gary