EGT Lean of Peak

[Conifer]

I have a Superior IO-360 on my RV7A,a Dynon D180 and a Generation 3i electronic ignition. I cannot go to lean of peak. The engine quits almost after reaching peak. For example 8500' 22 MAP 1479F at peak EGT and 10.7 GPH. My EGT probes are all 4 located at 21/2 inches from the port. The GPH given by the EMS is accurate up to 1/5 of a gallon. Is it a problem of probe location ? fuel injectors or else. Some told me that the probes are to far away from the port by at least 1/2 inch. Any solution suggested

[nomocom]

Welcome to the forum..

That engine behaviour does sound odd. However, don't worry about probe distance, doesn't matter, though wherever they are, it's nice if they are all the same distance.

I'd suggest more data. Try something like 12 gpm, write down all egt's, then 11 gpm, all egt's, then maybe half a gallon steps until she dies. Let us know what you find out. Note fuel flow where she goes rough or quits.

Just thinking outloud here, LOP operations are more demanding of the ignition system that ROP...maybe an issue there

[Martin Sutter]

I too have the same engine with dual P-mags in my 7A. At 8000' with power set at 22" and 2350 rpm 40 degrees lean of peak the fuel flow is 7.1gph. What is important is the fuel flow between the peak of the first cylinder versus the last one. On my engine that value is 0.3gph. This delta should be no more than 0.5gph for smooth lean of peak operation. The actual temperatures are are relative and depend on probe location. For example my GRT engine monitor installation manual allows for any distance between 2" and 8" from the exhaust port as long as it is the same for all probes.

Martin Sutter
building and flying RV's since 1988
EAA Technical Counselor

[AlexPeterson]

I have an injected O360, and here is some data from yesterday:

8500' indicated, 4C, 30.31, 2300 rpm, 22.7" WOT.

Fuel Flow, TAS (knots)
8.3, 171
7.9, 172
7.8, 170
7.5, 167
7.1, 164
6.9, 155

Peak at these power settings, which closely mirror yours, should be around 7.6 to 8 gph. I didn't record egt, but fastest speed should be just rich of peak.

You should be way rich of peak at 10+ gph at your power settings. Something is wrong - timing, fuel flow, ?.

[Steve N.]

[quote=Conifer;411643] For example 8500' 22 MAP 1479F at peak EGT and 10.7 GPH.

Is your electric fuel boost pump on? If so, your indicated fuel flow will be higher than when it is off. At least that's how mine works.

[David-aviator]

Originally Posted by Conifer

I have a Superior IO-360 on my RV7A,a Dynon D180 and a Generation 3i electronic ignition. I cannot go to lean of peak. The engine quits almost after reaching peak. For example 8500' 22 MAP 1479F at peak EGT and 10.7 GPH. My EGT probes are all 4 located at 21/2 inches from the port. The GPH given by the EMS is accurate up to 1/5 of a gallon. Is it a problem of probe location ? fuel injectors or else. Some told me that the probes are to far away from the port by at least 1/2 inch. Any solution suggested

Conifer,
If the OAT was like 0 degrees C, the indication is about normal. I can not fly lean of peak in very cold weather, the engine wants to quit probably due to the high density of the O2 being sucked in.

[Radomir]

No this does not look normal to me... and 0C is not terribly cold..(relatively speaking)... You should have no problems running LOP (at that alt/OAT)... (mine's running great LOP with same parameters)

If this was my plane, I'd try different ignition.

PS.. Location of your EGT probes is just fine..

Originally Posted by David-aviator

Conifer,
If the OAT was like 0 degrees C, the indication is about normal. I can not fly lean of peak in very cold weather, the engine wants to quit probably due to the high density of the O2 being sucked in.

[Conifer]

Originally Posted by Conifer

I have a Superior IO-360 on my RV7A,a Dynon D180 and a Generation 3i electronic ignition. I cannot go to lean of peak. The engine quits almost after reaching peak. For example 8500' 22 MAP 1479F at peak EGT and 10.7 GPH. My EGT probes are all 4 located at 21/2 inches from the port. The GPH given by the EMS is accurate up to 1/5 of a gallon. Is it a problem of probe location ? fuel injectors or else. Some told me that the probes are to far away from the port by at least 1/2 inch. Any solution suggested

.
Thanks for all your suggestions. Let me give you some precisions.
The problem existed prior to install Generation 3 ignition which is an electronic ignition system. The electronic ignition system works perfectly well and offers besides the redundancy aspect of the installation, the advantage to be able to switch from electronic to conventional mags (Slick) which are intact after installing the electronic ignition using a toggle switch on the panel. So I can say that the problem is still there and has nothing to do with the electronic ignition or conventional.
Following your suggestions, I plan to: 1- check the accuracy of the Dynon D180 EMS fuel flow by checking accurately the fuel consumed starting from a full tank in level cruise for half an hour and comparing the EMS fuel flow value and the actual quantity of fuel used.
2- Establish a spread sheet of parameters at 8500', 2300 RPM and 21" MAP starting from 70F ROP and slowly leaning by 0.2 GPH increment, noting the EGT for each cylinder until one cylinder starts to rattle. The following step being to get in touch with Precisiion Airmotive, give them the spread sheet and ask them if the situation can be remedied by changing the injector on one or several cylinders. This is the plan, any suggestions will be appreciated.

[N54SG]

Not sure if this is going to help at all, but I am dealing with the same issue.

Superior XP-400SRE
Precision Airmotive Silverhawk EX

Probes are all 2" down
Peak EGT ~1300 (low by comparison)
All peak within .1 gph (all 4 peak at exactly the same time)
Less then .1 gph past peak the engine quits
Now, my fuel flow is way different, so that isn't going to compare to the other engines.. about 10.5 gph at peak.

I have data logging that can get all 16 channels each minute, that is how I was able to get these numbers. Leaning .1 gph each minute.

Moral of the story, if you learn anything, would love to see what you find out.

Thanks

[yakdriver]

Are you using the lean find mode of the D180? Don