high egt on cylinders 1 and 2

I have an xpIO360 with 460hrs, with first flight april of 09.
electronic ignition with plasma 3 on top and pmag on bottom

Just recently I had a situation where no.1 and 2 all of the sudden went up in egt by about 100. This went on for several flights, than out of no where they went back to normal. normal is where cylender 1 at 1330 lean of peak, no2 1380, no3 1332, no4 1335. No2 was always a litttle higher. Than after about 50 hrs no1 and no2 again about 100 higher on the egt. peak would be later as well. Use to be no1 would peak first. now it's no3 peaking first. these are based on 20map and 2400rpm. c/c prop

1 week ago all the sudden no1 and no2 shot up higher, now about 250degrees higher and peak along with it, now no3 no4 is peaking normal and 1 and 2 last, with temps at 1550+.

This is a real kicker, when it first did this I landed looked things over, next day flew again, now everything is just fine. In fact the spread for the dynon lean of peak is .4. AArgh. But 1 and 2 are still about 100 higher.

Than after that flight, 1 and 2 is back to high temps of 250+ over 3 and 4.

This is what I have done.

Switched each mag off and the temps even across the board increase within 100 from each side. No change on 1 and 2 higher temps. engine runs good on single mag

I switched the egt between 1 and 3. That's wiring and all.
now the hot one goes to 3 on my dynon. So it's not the dynon or the probs

I pull all the injectors and clean them, that's with an ultra sonic cleaner and gun cleaning solvent. On top of that I take the injectors from 3 and 4 and put them in 1 and 2. Same thing, 1 and 2 running hot.
I also cleaned the spider.

I checked the clamps and bolts for the air intake tubes.

CHT are normal
oil temps are normal
If I were to close my eyes and not look at the ems I swear the engine is it's old self. That's with running lean of peak with 3 and 4.

trying to figure my next step, I think I've narrowed it down to the engine. I do fear a possible problem with the cam, looks like intake valves for 1 and 2 are using the same lobe.

appreciate all thoughts on this, trying to find the problem, really pulling my hair out on this one.

I pulled the plugs on 1 and 3 and they both look the same.

Check the coil

My IO-540 did this. The 2 rear cylinders are served by the same coil on my plasma ignition. Standard mag on the bottom. The connection to the coil broke. EGTs went up. New crimp on and voila. I suspect a bad coil would do the same.

Good luck.

I really wish it was that simple. I went and swapped coils, still problem with 1 and 2

If you haven't checked you may want to make sure you are getting power to the coil. That was the problem I had.

If the intake lobes were worn I think the EGT would go down not up.
If operating on a single ignition EGT will rise for all cylinders. If the ignition timing is changing EGT could go up or down depending on how the timing is changing but again for all cylinders. If valve is sticking open slightly or not sealing, or burnt the EGT will rise on that cylinder. If the exhaust system is letting oxygen in through a crack or leaky gasket then EGT will rise on that cylinder. Fouled or defective plug in a cylinder will case the EGT to rise in the cylinder that has the bad plug. Lean mixture to an individual cylinder will cause EGT to rise. If the nozzles are good, maybe a problem in the flow divider or supply lines to those cylinders.
Good Luck,
Mahlon
?The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

n981ms said:

If you haven't checked you may want to make sure you are getting power to the coil. That was the problem I had.

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Did your egt's go up and everything else stay the same. I assume that since I turned off the plasma 3 in cruise with those two cylenders that it would correct the real high temps. I'm getting in the range of 300 extra egts on 1 and 2. when I turn off the plasma the base stays high and all cylenders increase up to 100 across the board. I really want it to be the ei system. I do suspect the wire from the control unit to the coil. Than again it could be in the box

I called superior today and they gave me a way to check the cam. I will do that when I can, basically check the end gap on the valve stem to rocker arm. there is a special way since I have roller tappets. they also said to take the filter and cut it open and rinse the paper filter in solvent and run a magnet through it to see if there is a fine metal wear. that will also give me an indication.

On and Off

My 540 was built with a Slick on the LH side feeding the top plugs and an Electroair feeding the bottom plugs. All was well for about 240 hours. One fine morning at 12000 ft over the Sierra Rockies close to Banff, the EI decided it really wanted to be assigned to earth based duties. The Slick brought me home safe. Back on the ground the EI was not an easy thing to trouble shoot. It could not be made to fail on the ground. A few more flights over flat open terrain after replacing a few EI components eventually resulted in a second Slick mag like the Lycosaurus left the factory with. Nothing but joy and perhaps a few extra gallons burned since. The culprit in my case was a less than ideal trigger sensor mount bracket. Note worthy and perhaps relevant to your case is that every time the ignition would cut out in flight, the EGT's would rise about 100 degrees in all six cylinders. On a couple of test flights it would cut in after a 2 minute vacation and predictably all 6 EGT's would drop about 100 to previous levels. The on and off nature of your symptoms make me suspect ignition components that feed 1&2. A year or two ago there was a thread from a guy in Australia that was using dual LS EI's that developed symptoms similar to what you describe.

Good Luck!

I plan on replacing the wire for the 1 and 2 coil using bob's advice for wire. also I will be checking the end gap on the valve system to check the cam. sounds like a good thing to do regardless. thanks.

update

Ok, got to do some work on this. I replaced the wire for the 1,2 coil on the lightspeed. Same problem. I flew around and tried to get a handle on this. I found that the problem comes in at 15map on up. I also find that things settle down if I richen things up and going any lean at all the egt's go through the roof. there is no peak at all.

I land and pull things apart, the cam seems fine, the end gap for valve stem to rocker arm is right on for specs, I put the valve on full compression and measure to the head and check the good cylender, the same or close enough. OH and when I run it on the ground I can get it to do it as long as I run over 15map.

My next step was to remove the intake tubes, now I'm thinking a lean condition or leak. I pull the tubes and there it is, the gaskets are brittle and falling apart and you can see leaks on the gasket. The hose is real loose on the tube as well. So I really think I found the problem, time to order new gaskets and the hose for each cylender. Will see how things work out.

allbee said:

I plan on replacing the wire for the 1 and 2 coil using bob's advice for wire. also I will be checking the end gap on the valve system to check the cam. sounds like a good thing to do regardless. thanks.

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DO NOT, I repeat, DO NOT use anything but the recommended coax by LSE. Shielded wire has much higher capacitance per foot than does the recommended coax. This has an effect on primary rise time and causes a much greater load on the output circuitry as this is additional capacitance that must be charged and discharged. Rg-400 has 30 pf/ft, and shielded wire runs about 55pf/ft. That extra 25 pf/ ft for 3' with a rise time of 1 usec charging to 300V requires an additional load on the output transistor of 34 Amperes. Do you want to do that to your ignition? If you have a failure using that shielded wire your warranty is void. The person recommending that shielded wire never got output pulse characteristics from LSE, has no idea of the output waveform and voltage, and so can't recommend a proper replacement, and was told on many occasions to cease and desist.

thanks for the input, will put the old wire back on. I feel I found the problem with the intake gaskets.

allbee said:

thanks for the input, will put the old wire back on. I feel I found the problem with the intake gaskets.

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Great! Glad to hear that!

pf vs nf

I discovered that on my post this morning that when I calculated the current necessary to charge the additional capacitance of shielded cable I was talking picoFarads but calculating with nanoFarads and so I was off a little. Ok, more than a little. More like one thousand. But that's a lot less than the billions or trillions the gummint uses. Sorry!
But the main reason for not using the shielded wire is that it is doesn't have a high-enough voltage-breakdown rating. The resonant voltage in the LSE system is almost double the pulse voltage. If you get a dielectric breakdown in the cable causing it to arc, besides giving intermittent spark output, the output transistor could soon break down also, shutting down two cylinders. The breakdown rating of RG-400 is 1900V, more than enough.
If you decide to use or are using this shielded wire in your LSE system, make sure that the person recommending this wire to you and has sold it to you will warranty that if the wire breaks down and causes the EI to fail, he will pay for its repair! If you are using it and it hasn't caused a problem, at least that you know of, well, good luck! Keep watch for occasional roughness.
Never change anything to do with an aircraft or its equipment unless you have the blessing of the manufacturer. If not, you are now in the experimental world yourself, and you alone are responsible for any failure of your equipment or life.
BTW, have any of you that reported that you that had failures with your LSE and were using this shielded wire but you didn't tell Klaus about it ? For shame! 'Fess up, guys!

fix

I went to the FBO today and got me 4 gaskets AEL71973. Cost me 4 bucks and some change with tax. I went to the plane and installed all 4 intake gaskets. I flew her, my baby is fixed. I took it up to 7k and run it lean of peak and came out with .2 gph and about 7.5 gph. I'm very happy. Now those old gaskets where red and thin. they broke apart when I touched them. the new ones were a dark gray. I think they are an updated part here. My advice, if you have high egts and can't get peak. Change the intake gaskets first. What threw me off was 1,2 were doing it.

I feel fortunate that I let the dynon do the diagnoses and parts to fix was 4 dollars, can't beat that.

EGT

CHECK THE LITTLE SCREENS IN THE INJECTORS FOR BLOCKAGE, I HAVE SEEN TREE POLLEN PLUG THEM UP. DENNIS IO-360,RV-6

I was just reading this thread thinking one of two things......and you could guess how I know!

1. Spark plug gaps. Especially running LOP, as they will be found wanting LOP and running ROP masks the problem of increasing gap and poorer spark. Reason being a lean mixture takes more spark to get the combustion going. So what happens, just like doing a mag check (and always do it leaned out) is the slower combustion event continues on as the exhaust valve opens and the EGT probe sees a bit of the combustion. Hence the EGT's should all rise together when doing a mag check. Do one in flight LOP and you should see this too. A poor plug will show up really well and a poor mag will show up even better!

2. Inlet gaskets After 270 hours on a brand new Lycoming IO540 guess what happened to us. 5 out of six gaskets failed in quick time. Could not believe it. One of them had a gap of 1.5mm and no wonder it was running rough. They all crumbled. New gaskets =

DB