EGT rise/CHT drop IO360 RV-7

rv7-ksff · #1 08-23-2008, 09:49 AM

In cruise I noticed a fluctuating EGT in #2. It would rise 50-100 deg and fall back to normal operating temp. At one point the rise peaked and triggered an alarm on my DYNON 180. Initially thought it may be erroneous reading from probe, but then also had concurrent shock cooling alert on same #2 CYL for just a moment. Reducing power seemed to slow down the fluctuations. I have since pulled the plugs out and they look normal. All fuel lines appear tight and no leaking fuel is evident.

Looking for suggestions......

vic syracuse · #2 08-23-2008, 11:07 AM

You might check the probe and the wires going to it, especially if you didn't notice any other fluctuations, such as fuel flow or noise.

Vic

rv7-ksff · #3 08-23-2008, 11:45 AM

Quote:

Originally Posted by vic syracuse

You might check the probe and the wires going to it, especially if you didn't notice any other fluctuations, such as fuel flow or noise.

Vic

No other fluctuations, no noise, fuel flow was normal, but there was a reduction in same #2 cht. Haven't checked the probe yet. Going to change the plugs on #2 and test fly and if that doesn't change anything will next try to swap the probes out..... thanks

az_gila · #4 08-23-2008, 11:55 AM

...the injector on that cylinder?

Going way too lean, more EGT and less power/CHT...

airguy · #5 08-23-2008, 01:19 PM

Agreed - if you saw both CHT and EGT change at the same time on the same cylinder, you've either got spark or mixture issues. My bet is an obstruction in the injector causing it to go lean.

sprucemoose · #6 08-23-2008, 03:52 PM

Next time you notice that happening, try a mag check and see if it does it on one or the other or both mags. Low CHT/ high EGT means gas is burning in the pipe and not the cylinder, which could be a mag problem. However this is often accompanied by some engine roughness. Did you notice any roughness?

What kind of ignition system do you have and how many hours on it?

osxuser · #7 08-24-2008, 11:04 AM

Also look at perhaps an induction leak. Usually running ROP you'd see the cylinder get hotter, but if you near peak or LOP, then it would get cooler. Typically not something that's intermittent either, but I've seen some bad gaskets or loose hose clamps on the induction tubes do that kind of thing before.