High CHT and EGT on one cylinder
Moderators: Rick, Lance Murray
- haykinson
- 3 Diamonds Member
- Posts: 114
- Joined: Thu Apr 19, 2018 8:32 am
- First Name: ilya
- Aircraft Type: DA40NG
- Aircraft Registration: N724LA
- Airports: KSMO
- Has thanked: 36 times
- Been thanked: 48 times
High CHT and EGT on one cylinder
The new-to-me Diamond seems to have a consistently hot cylinder. During initial climb, temperatures climb into the 415-430° range, while the rest sit in the 380s or so. My typical procedure is to take off and within less than a minute to bring power back to 24-25 MP and 2400 RPM, and then continue my climb, but if I keep climbing below 85kts then the cylinder will continue to climb in temperature until it gets to mid-430s. In cruise, I have to go to 50-60% power or so in order to keep the cylinder below 400°. I tend to lean to 100° ROP The same cylinder is usually has the highest EGTs as well.
Here's a sample flight: https://www.diamondaviators.net/reports/flights/11539
The fact that this cylinder is running so hot means that I back off the power by quite a bit, but the engine should be able to run continuously at higher power. Has anyone seen this before, or have suggestions?
Here's a sample flight: https://www.diamondaviators.net/reports/flights/11539
The fact that this cylinder is running so hot means that I back off the power by quite a bit, but the engine should be able to run continuously at higher power. Has anyone seen this before, or have suggestions?
- krellis
- 4 Diamonds Member
- Posts: 339
- Joined: Fri Apr 29, 2011 10:42 am
- First Name: Keith
- Aircraft Type: OTHER
- Aircraft Registration: N853DF
- Airports: GA04
- Has thanked: 1 time
- Been thanked: 63 times
Re: High CHT and EGT on one cylinder
If you are running ROP and you have both high CHT and EGT, you might have a clogged injector.
- Rich
- 5 Diamonds Member
- Posts: 4592
- Joined: Mon Aug 30, 2010 12:40 pm
- First Name: Rich
- Aircraft Type: DA40
- Aircraft Registration: N40XE
- Airports: S39 Prineville OR
- Has thanked: 145 times
- Been thanked: 1180 times
Re: High CHT and EGT on one cylinder
I never see this kind of disparity. I'll offer an off-the-wall pair of suggestions:
1. Could you have GAMI injectors installed into the wrong cylinders?
2. If not (or you don't know), run a bottle test to see that the injectors are delivering fuel at the same rate to each cylinder.
When the throttle is full forward, there is an extra enrichment provided to all cylinders. Pulling back on the throttle cuts fuel flow. I just leave throttle full forward until I'm done climbing and sometimes leave it there, if I'm high enough. I monitor mixture during the climb to maintain ~1300 degF EGT. Cutting back RPM should help CHT's, so I note no obvious problem there.
1. Could you have GAMI injectors installed into the wrong cylinders?
2. If not (or you don't know), run a bottle test to see that the injectors are delivering fuel at the same rate to each cylinder.
When the throttle is full forward, there is an extra enrichment provided to all cylinders. Pulling back on the throttle cuts fuel flow. I just leave throttle full forward until I'm done climbing and sometimes leave it there, if I'm high enough. I monitor mixture during the climb to maintain ~1300 degF EGT. Cutting back RPM should help CHT's, so I note no obvious problem there.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
- haykinson
- 3 Diamonds Member
- Posts: 114
- Joined: Thu Apr 19, 2018 8:32 am
- First Name: ilya
- Aircraft Type: DA40NG
- Aircraft Registration: N724LA
- Airports: KSMO
- Has thanked: 36 times
- Been thanked: 48 times
Re: High CHT and EGT on one cylinder
That was our first idea as well, but cleaning produced no benefit.krellis wrote:If you are running ROP and you have both high CHT and EGT, you might have a clogged injector.
- haykinson
- 3 Diamonds Member
- Posts: 114
- Joined: Thu Apr 19, 2018 8:32 am
- First Name: ilya
- Aircraft Type: DA40NG
- Aircraft Registration: N724LA
- Airports: KSMO
- Has thanked: 36 times
- Been thanked: 48 times
Re: High CHT and EGT on one cylinder
Looking at the logs, there's no record of GAMI injectors being used.Rich wrote:1. Could you have GAMI injectors installed into the wrong cylinders?
I've got the 100hr fuel injector line check coming up in 20 hrs, I guess I can just move that up by a bit and have them run such a test.Rich wrote:2. If not (or you don't know), run a bottle test to see that the injectors are delivering fuel at the same rate to each cylinder.
I think I still suffer from not wanting to go "over square", though nothing in the POH suggests that's a problem. I'll see what keeping the climb at full throttle but lower RPM does to the CHTs, though I suspect that if the problem exists in cruise as well then it's not a climb then it's not just throttle management that's at issue.Rich wrote:When the throttle is full forward, there is an extra enrichment provided to all cylinders. Pulling back on the throttle cuts fuel flow. I just leave throttle full forward until I'm done climbing and sometimes leave it there, if I'm high enough. I monitor mixture during the climb to maintain ~1300 degF EGT. Cutting back RPM should help CHT's, so I note no obvious problem there.
- astaib
- 5 Diamonds Member
- Posts: 616
- Joined: Mon Feb 26, 2018 9:00 pm
- First Name: Arnaud
- Aircraft Type: DA40
- Aircraft Registration: FGNJX
- Airports: LFPX
- Has thanked: 244 times
- Been thanked: 51 times
Re: High CHT and EGT on one cylinder
Hello,
I had exactly the same thing with mine since the engine was overhauled last year.
We have tried many actions to understand:
Injector cleaning
CHT probe swaping/changing to new
Fuel divider cleaning
Injectors tests
Contacting Diamond
The cylinder #1 has been returned for inspection
Oil analysis
...
=> No results
One day when I was looking into the engine compartment when the cowling was remove, I noticed that the rod retainer for the baffle were not there. It seems that they were lost during the overhaul. The workshop replace the rods and the difference between CHT #1 and the other fell down from 50°F to 20°F.
Then we continued to explore in this direction and we have inspected the baffle themselves and their seals.
Both of them (baffles and seals) were old, baffles cracked, seal not anymore sticking to the cowling...
We changed baffles and seals to new and the problem is gone.
Don't think that cylinder #1 should be the coolest one because he is in front position, when you look closer at the air flow inside the engine compartment, cylinder #1 is not the first to receive the fresh air.
Since that I heard from other Diamond owner that they have the same experience as me with the baffles/seals.
Try to change the seals only first because it can be enough, and because the baffles are expensive.
Have a good day.
Arnaud.
I had exactly the same thing with mine since the engine was overhauled last year.
We have tried many actions to understand:
Injector cleaning
CHT probe swaping/changing to new
Fuel divider cleaning
Injectors tests
Contacting Diamond
The cylinder #1 has been returned for inspection
Oil analysis
...
=> No results
One day when I was looking into the engine compartment when the cowling was remove, I noticed that the rod retainer for the baffle were not there. It seems that they were lost during the overhaul. The workshop replace the rods and the difference between CHT #1 and the other fell down from 50°F to 20°F.
Then we continued to explore in this direction and we have inspected the baffle themselves and their seals.
Both of them (baffles and seals) were old, baffles cracked, seal not anymore sticking to the cowling...
We changed baffles and seals to new and the problem is gone.
Don't think that cylinder #1 should be the coolest one because he is in front position, when you look closer at the air flow inside the engine compartment, cylinder #1 is not the first to receive the fresh air.
Since that I heard from other Diamond owner that they have the same experience as me with the baffles/seals.
Try to change the seals only first because it can be enough, and because the baffles are expensive.
Have a good day.
Arnaud.
Arnaud
DA40 Star 180 / 40.026 / 2001
Wingtip, landing and taxing LED (Whelen)
Skitube
GNS430 NON-WAAS
Steam gauges
Non certified ADS-b
DA40 Star 180 / 40.026 / 2001
Wingtip, landing and taxing LED (Whelen)
Skitube
GNS430 NON-WAAS
Steam gauges
Non certified ADS-b
- Rich
- 5 Diamonds Member
- Posts: 4592
- Joined: Mon Aug 30, 2010 12:40 pm
- First Name: Rich
- Aircraft Type: DA40
- Aircraft Registration: N40XE
- Airports: S39 Prineville OR
- Has thanked: 145 times
- Been thanked: 1180 times
Re: High CHT and EGT on one cylinder
Because your EGT show a significant imbalance and you say your CHT's are following the EGT pattern, I still suspect mixture problems. I see #1&2 EGT's are pretty close and 3&4 are pretty close, but a persistent gap between the pairs. The 2 front cylinders are running higher EGT's than the rear. The injectors aren't the only thing that influence fuel flow. The distributor that sits on top of the engine might have a problem. These have been known to get AD's issued against them.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
- astaib
- 5 Diamonds Member
- Posts: 616
- Joined: Mon Feb 26, 2018 9:00 pm
- First Name: Arnaud
- Aircraft Type: DA40
- Aircraft Registration: FGNJX
- Airports: LFPX
- Has thanked: 244 times
- Been thanked: 51 times
Re: High CHT and EGT on one cylinder
Hi Rich,
Which AD's are you talking about please?
Arnaud.
Which AD's are you talking about please?
Arnaud.
Arnaud
DA40 Star 180 / 40.026 / 2001
Wingtip, landing and taxing LED (Whelen)
Skitube
GNS430 NON-WAAS
Steam gauges
Non certified ADS-b
DA40 Star 180 / 40.026 / 2001
Wingtip, landing and taxing LED (Whelen)
Skitube
GNS430 NON-WAAS
Steam gauges
Non certified ADS-b
- Rich
- 5 Diamonds Member
- Posts: 4592
- Joined: Mon Aug 30, 2010 12:40 pm
- First Name: Rich
- Aircraft Type: DA40
- Aircraft Registration: N40XE
- Airports: S39 Prineville OR
- Has thanked: 145 times
- Been thanked: 1180 times
Re: High CHT and EGT on one cylinder
I'd have to dig, but I remember getting one and having to check model/serial number for applicability (it didn't apply to my plane). I believe I have a record of it, but I'm sure it was 10 years ago or more.astaib wrote:Hi Rich,
Which AD's are you talking about please?
Arnaud.
My point is these things can malfunction, AD or not.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5