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  #1  
Old 01-18-2020, 02:27 PM
AHelliwell AHelliwell is offline
 
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Location: Sun City, California
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Default High EGT and CHT on #4, IO 360

I have a high reading on my #4 EGT 1500+, CHT 361, on IO 360 RV-7 at full throttle departure 2600 rpm. We have checked and changed the spark plugs and switched the sensor. We believe there are no air leaks. Have not yet checked the injectors, as the aircraft has an extended cowl. Temp remains the same.
Please help with advice for the next step.
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  #2  
Old 01-18-2020, 02:35 PM
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BlackhawkSP BlackhawkSP is offline
 
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Quote:
Originally Posted by AHelliwell View Post
I have a high reading on my #4 EGT 1500+, CHT 361, on IO 360 RV-7 at full throttle departure 2600 rpm. We have checked and changed the spark plugs and switched the sensor. We believe there are no air leaks. Have not yet checked the injectors, as the aircraft has an extended cowl. Temp remains the same.
Please help with advice for the next step.
If in fact there are no air leaks, making that cylinder run lean, then next step is to check the fuel line to that cylinder for an obstruction. You might flow the four lines checking for balanced flow.
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  #3  
Old 01-18-2020, 02:57 PM
lr172 lr172 is offline
 
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Quote:
Originally Posted by AHelliwell View Post
I have a high reading on my #4 EGT 1500+, CHT 361, on IO 360 RV-7 at full throttle departure 2600 rpm. We have checked and changed the spark plugs and switched the sensor. We believe there are no air leaks. Have not yet checked the injectors, as the aircraft has an extended cowl. Temp remains the same.
Please help with advice for the next step.
what is high power peak EGT on #4? Mixture can't make EGT go higher than typical peak EGT. Timing, however, can. When one cyl EGT goes above normal peak EGT, it usually means retarded timing, typically due to only one plug firing. CHT typically drops a bit from normal in this case. With only one plug firing, you should expect EGT at least 100* higher than normal for that power configuration.

If normal peak EGT is 1500 or above, I would be looking at a plugged injector. intake leaks typically show no symptoms at WOT / full power. They are more obvious at low MAP operations. if normal TO power normally delivers 1300 EGTs, the 1500 you are seeing could still be from one plug firing even if 1500 is below typical peak EGT. If injector isn't plugged, check the two plug wires.

Larry
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Last edited by lr172 : 01-18-2020 at 03:17 PM.
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  #4  
Old 01-18-2020, 02:58 PM
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bjdecker bjdecker is offline
 
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Location: Georgetown, TX
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For reference sake -- 361F is about what I see on my RV-7 with an IO-360-A1B6, stock cowl during a full power climbout @2700RPM 29"MAP, 16GPH, 15C OAT...

2600RPM is a bit low for full power ops -- what does it do at 2700RPM?
How about your power (How many " MAP, what altitude?), what's your fuel flow and pressure?
How does #4 EGT & CHT compare to the other three cylinders?
Has it always behaved this way, or did it just start?
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  #5  
Old 01-19-2020, 10:28 AM
AHelliwell AHelliwell is offline
 
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Thanks so much everyone. I believe we may have fixed the problem. Found some manifold air leaks on cylinders #2 and #3. Weird as it manifested on the instrument in the panel on #4. Looks like it brought temps back to even with all cylinders. I'm going up today to confirm.
Really appreciate all the replies to help me.
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  #6  
Old 01-19-2020, 10:54 AM
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Mike S Mike S is offline
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Quote:
Originally Posted by AHelliwell View Post
Found some manifold air leaks on cylinders #2 and #3. Weird as it manifested on the instrument in the panel on #4.
Have you checked to make sure all temp probe wiring is to the correct cylinders??
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  #7  
Old 01-19-2020, 12:38 PM
lr172 lr172 is offline
 
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Quote:
Originally Posted by AHelliwell View Post
Thanks so much everyone. I believe we may have fixed the problem. Found some manifold air leaks on cylinders #2 and #3. Weird as it manifested on the instrument in the panel on #4. Looks like it brought temps back to even with all cylinders. I'm going up today to confirm.
Really appreciate all the replies to help me.
While every plane is different , 1500 is a typical peak egt. If you are still getting that at full power down low, you likely need to address something.
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  #8  
Old 01-19-2020, 09:13 PM
AHelliwell AHelliwell is offline
 
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Quote:
Originally Posted by Mike S View Post
Have you checked to make sure all temp probe wiring is to the correct cylinders??
Not yet, on my next day off I will keep working on it. Looks like #3 had the air leak and EGT on #4 is corrected. At least I can fly.
Thanks for your input.
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  #9  
Old 01-19-2020, 09:19 PM
AHelliwell AHelliwell is offline
 
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Location: Sun City, California
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Quote:
Originally Posted by Mike S View Post
Have you checked to make sure all temp probe wiring is to the correct cylinders??
Not yet, but:
On my next day off I will keep working on it. Looks like #3 had the air leak and EGT on #4 is corrected. At least I can fly.
Thanks for your input.
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