hi folks, wanted to share some personal experience and share my experience with these much recurring topics that hopefully one can benefit from (or enhance).
- Systems: Plane, engine, pilot detail
- Intro as to why this note
- Synopsis; Detailed explanation of the symptoms and troubleshooting them
- Vendor support (JPI, ElectroAir, Lycoming, Aircraft Spruce)
- What about TBO
- Closing
SYSTEMS:
- Plane: 1972 PA-28R-200 (privately owned), flown minimally once a week for a total of about 80-100hr/yr since ownership
- Engine: IO-360-C1C/Electroair ignition system on one
- Monitor JPI-EDM900
- Pilot: 500hr, 11yr, 1.5yr owner
General operation:
- cruise 65%, LOP -50/-70 (23/2350) - 55% LOP -25/60 (22/2150) (alt 2000-3000)
- taxi: lean to "E"
- climb at WOT/maxrpm (2650/2700), once established climb, rpm 2600 and 28->26 MAP/rich
INTRO:
As a (new) owner of a(n older) plane, there is much new coming at you and sometimes you don't know whether to be worried and it can be overwhelming. Many different opinions exist, and this to share a personal experience I hope will be beneficial for those in the same boat.
Last 3 months I had 2 engine run up items : first time, the engine during runup on EIS only would shut down, the 2nd time the engine was running extremely rough noting EGT high on one cyl higher then usual and >100 diff between the 2nd inline, that CHT being lower in cruise, normally the hottest (cyl #2 to be specific).
SYNOPSIS:
-Issue 1:
Few months ago, noticed a longer starting crank needed to get the engine going. Std procedure is to start on EIS only and when running, enable the Mag. That was in March and thought this could be a sign of morning sickness (rough start, getting better as it warms up, potentially related to be sticky valve?).
With EIS and during a normal runup, I would not see any RPM drop on the EIS only and the usual 50-60 rpm drop on mag only.
2 flights after, I couldn't start it on the EIS only, enabled both EIS and mag and started fine. During run up, the magneto check showed an engine shutdown if I'd switch off the EIS.
Flight cancelled obviously.
Called Electroair. Got a very firm answer:
Sensor on the MTH (magnetic timing house, eg the part that replaces the magneto to tell the EIS system where the crank shaft is for ignition timing), is likely out.
Take a multimeter, disconnect it and measure the resistance, read between 900-1100 ohms (2 types of sensors, each with their own resistance), mine read 5M ohms!
So that needed to be replaced. Got the replacement in ok (instructions are great and super easy) and I was back up like I was before!!
The troubleshooting guide for the EIS system is good, but it misses a few checks, like that ohm check is super helpful.
- Issue 2:
Having dealt with issue 1 prior, and drGoogle providing whatever you want to hear (its not that bad, or it is very bad), and while I had been on top of my EDM900, downloading stats frequently, analyzing them, I became what I noticed very very picky on every little "off" sign that I needed to have an explanation for.
Since about since a month, she started just fine, but there was always that "plop" sound after engine start. I didn't like that. Google searches were either morning sickness, too rich on start, too much prime. Ok so I tuned that all back. Throttle on "E" (1/4" open), Master on, Fuel pump on, Mixture rich, count to 3, ICO, crank.
I used to start count to 3 when I saw the FF rising, so that is realistically a 5-6 second prime. So keeping it 3 seconds from mixture full rich to ICO and not watch fuel flow (unless it is a cold winter day) she started much better, without plop, BUT somewhat rough: RPM boost, tapering off, and getting back to it. Throttle down to 1000rpm everything cool.
You'd think...
This sounds very much like morning sickness. Do I have a sticky valve after all? Could I bend the rod and be in more trouble.
Runup is fine, maybe some contamination on the plug, do the usual 172 trick of runup with RPM, lean mixture and cycle magneto 30 seconds on each side to burn off.
Now EGT on cyl#2 is going all over the place. All EGT's are normally 1150-ish (at runup) plus or minus 50, that is what I am used to.
AND I am starting to see an RPM drop of about 50-100 on the EIS alone, that NEVER happened.
To determine some factors, decided to make a flight in the pattern of the class-D airspace I am based out of and establish a few things in flight. Spoke with the controller, explained the need for a test flight and that I possibly needed an immediate landing back. Could be accommodated. Felt safe enough to undertake this test.
During climb, normally hottest CHT#2 was not the hottest, it was the usual next inline CHT#3. CHT#2 was third hottest.
In retrospect, I should NOT have done this. It could have been done on the ground... (therefore this story also).
What about EGT? EGT was hotter than normal and by a lot. EDM started to bark at me EGT difference was 150.
On the downwind, I leaned as if I was in cruise and the engine was abnormally rough. With the CHT#2 being much cooler and the EGT#2 much higher. I immediately enriched and that reduced the roughness, wondering if I had f'd up my engine by always running LOP. Doing an extended downwind to verify LOP/ROP one more time the experience was consistent. Back down on the ILS for 15, landed fine, this was not good.
Tried to do a runup and medium RPM (1500) and do a mag check. A sticky valve does not expose itself with these parameters (low CHT high EGT during cruise), the roughness would generally minimize after warm up/run up and I had it persistent now. Could this be detonation or preignition one of my other constant worries.
One great reference is this on pre-ignition and detonation: https://resources.savvyaviation.com/detonation-and-pre-ignition/
I have the reverse: cool CHT and high EGT.
High EGT generally comes from combustion happening in the exhaust side, eg you're too rich. But I was running LOP during the test flight
Or....... if you have a failing plug, not all of the fuel is ignited and due to heat, part of it, like an after burner, ignites in the exhaust cycle.
How to differentiate between all this?
Trick applied is to run up, with warm engine, then do magneto check and evaluate the drop on either side. Run it for 30 seconds Left then Right and observe EGT and CHT.
Do this with a leaner mixture and a richer mixture.
Observation was on the EIS alone, CHT#2 was lowering and EGT was dropping to near zero. While other Cyl's were in their 1000's
There was NO combustion in #2 and a sign of a failed spark plug.
Just to explain, on both MAG+EIS, the mixture is not completely burnt and possibly combusts in exhaust increasing EGT.
On MAG alone, this phenomenon still exists
On EIS alone, with bad plug, there is no combustion at all hence CHT dropping and EGT as well.
ps. has nothing to do with EIS, I had it suspect since it failed before. For all intends and purposes I could have called it Left or Right Magneto.
When doing a runup on a too lean mixture at a high-ish RPM (1500+), on one magneto, the engine will run rough and the EGT's will spike high.
Why? Investigated that too, because the too lean mixture that is barely combustable, especially on a single spark (one side mag only) and some of the mixture will reach the exhaust, combust and raise EGT, this is what I confused as detonation.
Pulled all plugs, and indeed, the Cyl#4 plug tied to the EIS had no tip on it anymore!!!!
Wait, I wrote cyl#2 the whole time... EDM wired incorrectly. Suspected that, cyl#2 = pilot front, it can't be more hot than the one behind, cyl#4 (getting the least airflow).
It's frustrating you have to 2nd guess certified install. GA pilots sets us aside that we use tools and automation as a help not as a replacement for intelligence (exception IMC+attitude indicators
The faulty plug is special and is EIS specific, they need to be thin wire of a special electroair certified as part of their STC and they are ~200 a piece.
Standard or "massive" plugs are $45.
So should I replace all plugs then? Its been 6 years since last and plugs are TBO of 300-500 it says. Yup there a new learning... Part of the next section.
VENDOR SUPPORT:
Let me describe by vendor my experiences:
JPI
In terms of FF, FP, CHT, EGT I am 100% reliant on the JPI EDM.
My disappointment with JPI is the engine files are a specific non standard format. JPI has free SW for windows only. Use the app, save it as CSV and do whatever you like.
Savvy Analysis is a web based neat tool but I feel I am like a facebook subscriber where they can learn from me, and if it is free, you're likely the product.
3 Surprising items:
- when I asked EDM about the CHT#2 high reading it not lining up with my mental picture and asked if this was normal, the answer was talk to your mechanic.
- when I asked about fuel pressure readings it fluctuating between 21.5 and 22.5 if that spread is ok (as in the graphs it shows a sawtooth) and I wanted to see if this was expected
or a transducer on its way out or indicative of a pump issue or something, a pointer. Talk to your mechanic.
I mentioned I spoke to him about it and it wouldn't be a bad idea to check with the manufacturer, you, to see if this is a characteristic of the transducer or not. Answer: find a new mechanic.
- there is no desire to share the dataformat of the .jpi files for manual decoding.
In today's world of open source, I can't see the intellectual property behind a compressed text based storage method, but ok... Creating more adoption I think is key to running a successful business...
On the good side, I don't see how you can lean properly without it. If one uses it in a Qualitive manner, as in you go by the _difference in_values, Delta's to determine off or onset of issues I think it is a realistic approach. I'll explain more in the Lycoming section as well.
If you look at the Quantitive side of things, eg, the absolute values, I think I have been freaking myself out more then need be. CHT excluded btw.
For example the EGT value is insignificant, it is the difference between peak and value that is significant (the whole LOP/ROP story).
Also every mechanic I spoke to confirms the same, there is nothing you can do to damage the engine with higher EGT.
<to be continued in part 2, character limitation hit>
- Systems: Plane, engine, pilot detail
- Intro as to why this note
- Synopsis; Detailed explanation of the symptoms and troubleshooting them
- Vendor support (JPI, ElectroAir, Lycoming, Aircraft Spruce)
- What about TBO
- Closing
SYSTEMS:
- Plane: 1972 PA-28R-200 (privately owned), flown minimally once a week for a total of about 80-100hr/yr since ownership
- Engine: IO-360-C1C/Electroair ignition system on one
- Monitor JPI-EDM900
- Pilot: 500hr, 11yr, 1.5yr owner
General operation:
- cruise 65%, LOP -50/-70 (23/2350) - 55% LOP -25/60 (22/2150) (alt 2000-3000)
- taxi: lean to "E"
- climb at WOT/maxrpm (2650/2700), once established climb, rpm 2600 and 28->26 MAP/rich
INTRO:
As a (new) owner of a(n older) plane, there is much new coming at you and sometimes you don't know whether to be worried and it can be overwhelming. Many different opinions exist, and this to share a personal experience I hope will be beneficial for those in the same boat.
Last 3 months I had 2 engine run up items : first time, the engine during runup on EIS only would shut down, the 2nd time the engine was running extremely rough noting EGT high on one cyl higher then usual and >100 diff between the 2nd inline, that CHT being lower in cruise, normally the hottest (cyl #2 to be specific).
SYNOPSIS:
-Issue 1:
Few months ago, noticed a longer starting crank needed to get the engine going. Std procedure is to start on EIS only and when running, enable the Mag. That was in March and thought this could be a sign of morning sickness (rough start, getting better as it warms up, potentially related to be sticky valve?).
With EIS and during a normal runup, I would not see any RPM drop on the EIS only and the usual 50-60 rpm drop on mag only.
2 flights after, I couldn't start it on the EIS only, enabled both EIS and mag and started fine. During run up, the magneto check showed an engine shutdown if I'd switch off the EIS.
Flight cancelled obviously.
Called Electroair. Got a very firm answer:
Sensor on the MTH (magnetic timing house, eg the part that replaces the magneto to tell the EIS system where the crank shaft is for ignition timing), is likely out.
Take a multimeter, disconnect it and measure the resistance, read between 900-1100 ohms (2 types of sensors, each with their own resistance), mine read 5M ohms!
So that needed to be replaced. Got the replacement in ok (instructions are great and super easy) and I was back up like I was before!!
The troubleshooting guide for the EIS system is good, but it misses a few checks, like that ohm check is super helpful.
- Issue 2:
Having dealt with issue 1 prior, and drGoogle providing whatever you want to hear (its not that bad, or it is very bad), and while I had been on top of my EDM900, downloading stats frequently, analyzing them, I became what I noticed very very picky on every little "off" sign that I needed to have an explanation for.
Since about since a month, she started just fine, but there was always that "plop" sound after engine start. I didn't like that. Google searches were either morning sickness, too rich on start, too much prime. Ok so I tuned that all back. Throttle on "E" (1/4" open), Master on, Fuel pump on, Mixture rich, count to 3, ICO, crank.
I used to start count to 3 when I saw the FF rising, so that is realistically a 5-6 second prime. So keeping it 3 seconds from mixture full rich to ICO and not watch fuel flow (unless it is a cold winter day) she started much better, without plop, BUT somewhat rough: RPM boost, tapering off, and getting back to it. Throttle down to 1000rpm everything cool.
You'd think...
This sounds very much like morning sickness. Do I have a sticky valve after all? Could I bend the rod and be in more trouble.
Runup is fine, maybe some contamination on the plug, do the usual 172 trick of runup with RPM, lean mixture and cycle magneto 30 seconds on each side to burn off.
Now EGT on cyl#2 is going all over the place. All EGT's are normally 1150-ish (at runup) plus or minus 50, that is what I am used to.
AND I am starting to see an RPM drop of about 50-100 on the EIS alone, that NEVER happened.
To determine some factors, decided to make a flight in the pattern of the class-D airspace I am based out of and establish a few things in flight. Spoke with the controller, explained the need for a test flight and that I possibly needed an immediate landing back. Could be accommodated. Felt safe enough to undertake this test.
During climb, normally hottest CHT#2 was not the hottest, it was the usual next inline CHT#3. CHT#2 was third hottest.
In retrospect, I should NOT have done this. It could have been done on the ground... (therefore this story also).
What about EGT? EGT was hotter than normal and by a lot. EDM started to bark at me EGT difference was 150.
On the downwind, I leaned as if I was in cruise and the engine was abnormally rough. With the CHT#2 being much cooler and the EGT#2 much higher. I immediately enriched and that reduced the roughness, wondering if I had f'd up my engine by always running LOP. Doing an extended downwind to verify LOP/ROP one more time the experience was consistent. Back down on the ILS for 15, landed fine, this was not good.
Tried to do a runup and medium RPM (1500) and do a mag check. A sticky valve does not expose itself with these parameters (low CHT high EGT during cruise), the roughness would generally minimize after warm up/run up and I had it persistent now. Could this be detonation or preignition one of my other constant worries.
One great reference is this on pre-ignition and detonation: https://resources.savvyaviation.com/detonation-and-pre-ignition/
I have the reverse: cool CHT and high EGT.
High EGT generally comes from combustion happening in the exhaust side, eg you're too rich. But I was running LOP during the test flight
Or....... if you have a failing plug, not all of the fuel is ignited and due to heat, part of it, like an after burner, ignites in the exhaust cycle.
How to differentiate between all this?
Trick applied is to run up, with warm engine, then do magneto check and evaluate the drop on either side. Run it for 30 seconds Left then Right and observe EGT and CHT.
Do this with a leaner mixture and a richer mixture.
Observation was on the EIS alone, CHT#2 was lowering and EGT was dropping to near zero. While other Cyl's were in their 1000's
There was NO combustion in #2 and a sign of a failed spark plug.
Just to explain, on both MAG+EIS, the mixture is not completely burnt and possibly combusts in exhaust increasing EGT.
On MAG alone, this phenomenon still exists
On EIS alone, with bad plug, there is no combustion at all hence CHT dropping and EGT as well.
ps. has nothing to do with EIS, I had it suspect since it failed before. For all intends and purposes I could have called it Left or Right Magneto.
When doing a runup on a too lean mixture at a high-ish RPM (1500+), on one magneto, the engine will run rough and the EGT's will spike high.
Why? Investigated that too, because the too lean mixture that is barely combustable, especially on a single spark (one side mag only) and some of the mixture will reach the exhaust, combust and raise EGT, this is what I confused as detonation.
Pulled all plugs, and indeed, the Cyl#4 plug tied to the EIS had no tip on it anymore!!!!
Wait, I wrote cyl#2 the whole time... EDM wired incorrectly. Suspected that, cyl#2 = pilot front, it can't be more hot than the one behind, cyl#4 (getting the least airflow).
It's frustrating you have to 2nd guess certified install. GA pilots sets us aside that we use tools and automation as a help not as a replacement for intelligence (exception IMC+attitude indicators
The faulty plug is special and is EIS specific, they need to be thin wire of a special electroair certified as part of their STC and they are ~200 a piece.
Standard or "massive" plugs are $45.
So should I replace all plugs then? Its been 6 years since last and plugs are TBO of 300-500 it says. Yup there a new learning... Part of the next section.
VENDOR SUPPORT:
Let me describe by vendor my experiences:
JPI
In terms of FF, FP, CHT, EGT I am 100% reliant on the JPI EDM.
My disappointment with JPI is the engine files are a specific non standard format. JPI has free SW for windows only. Use the app, save it as CSV and do whatever you like.
Savvy Analysis is a web based neat tool but I feel I am like a facebook subscriber where they can learn from me, and if it is free, you're likely the product.
3 Surprising items:
- when I asked EDM about the CHT#2 high reading it not lining up with my mental picture and asked if this was normal, the answer was talk to your mechanic.
- when I asked about fuel pressure readings it fluctuating between 21.5 and 22.5 if that spread is ok (as in the graphs it shows a sawtooth) and I wanted to see if this was expected
or a transducer on its way out or indicative of a pump issue or something, a pointer. Talk to your mechanic.
I mentioned I spoke to him about it and it wouldn't be a bad idea to check with the manufacturer, you, to see if this is a characteristic of the transducer or not. Answer: find a new mechanic.
- there is no desire to share the dataformat of the .jpi files for manual decoding.
In today's world of open source, I can't see the intellectual property behind a compressed text based storage method, but ok... Creating more adoption I think is key to running a successful business...
On the good side, I don't see how you can lean properly without it. If one uses it in a Qualitive manner, as in you go by the _difference in_values, Delta's to determine off or onset of issues I think it is a realistic approach. I'll explain more in the Lycoming section as well.
If you look at the Quantitive side of things, eg, the absolute values, I think I have been freaking myself out more then need be. CHT excluded btw.
For example the EGT value is insignificant, it is the difference between peak and value that is significant (the whole LOP/ROP story).
Also every mechanic I spoke to confirms the same, there is nothing you can do to damage the engine with higher EGT.
<to be continued in part 2, character limitation hit>