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Fuel injection problems yesterday.

pierre smith

Well Known Member
Coming back from the Race to Ridgeland in South Carolina yesterday, my -10 suddenly showed highly elevated EGT's for no apparent reason. I had been running 23"/2350 RPM and ROP, around 1330 EGT and all of them suddenly went to 1410/1430 without me touching anything. I had been running 15.4 GPH, so I enriched the mixture to lower the EGT's to near 17 GPH.

They did come down a little, to just under 1400 degrees with fuel flow at 17 GPH. The CHT's had not risen at all during this episode, so I suspected a Dynon problem. (D-120 EMS).

I also considered the fact that I may have developed a fuel leak under the hood, so I braced myself for a possible in-flight fire and was ready to shut the fuel off. If the engine was truly starving at 17 GPH, all of the fuel must not be reaching the injectors, hence the high EGT's, no?

I remembered Todd Swezey's cockpit fire and explosion at Ridgeland a few years ago, so I decided to NOT touch the flap switch in case there was fuel in the tunnel, and landed fast and long at home.

I will de-cowl the airplane and I'll report back.

Opinions anyone?

Best,
 
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I had been running 15.4 GPH, so I enriched the mixture to lower the EGT's to near 17 GPH.

They did come down a little, to just under 1400 degrees with fuel flow at 17 GPH. The CHT's had not risen at all during this episode, so I suspected a Dynon problem. (D-120 EMS).

What was the reason for enriching? Was it just to see what would change? EGT of over 1400 do not mean anything is wrong. When you enrichened what did the CHTs do?
 
Philip, the EGT's were at peak...not good, so I enriched it to lower them. Strangely, the CHT's hadn't changed during all this.??? The puzzling thing is that all of the EGT's rose simultaneously without me having done anything, by almost 100 degrees.

Best,
 
mags

Did it run rougher when this happened? If 1 mag goes dead it will do this . Or if the timing somehow changes.
 
Pierre,
Isn't that a symptom of one ignition going bad? Ah, others beat me to it.
 
Hmmm...

Y'know, I was limpimg home with only 11.5 volts showing and it may well have been the Lightspeed failing,,,hmmmmm? Yep, it was also accompanied by a loss of several MPH, but I thought that the Lightspeed only needed aroun 9 volts, no?

Yep....could be.

Thanks,
 
Y'know, I was limpimg home with only 11.5 volts showing and it may well have been the Lightspeed failing,,,hmmmmm? Yep, it was also accompanied by a loss of several MPH, but I thought that the Lightspeed only needed aroun 9 volts, no?

Yep....could be.

Thanks,

11.5 volts, Pierre?

You've got an electric problem not a fuel injection problem.

I've had EI and it comes with a double edged sword, its good when all is well but can get mighty weird when all is not well.

Good luck in sleuthing out the problem, with the alternator up and running it may be fixed.
 
My first thought would also be ignition. I've had one side die in flight and that's exactly what my EGT did as well.
 
Pierre,

I think you might be dealing with two issues. The lightspeed will work on 11.5 V but, it sounds like you lost your alt and could have spiked the lightspeed box. Seen it happen a few times. Also check the wiring to the coils for arc at the connectors. :) A dead Mag will cause the EGT issue, but does not explain the 11.5 volt issue.
 
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Ignition problems

I have same experience ,my lightspeed died,for excess of temperature,this happen 2 years ago,when call the company ,they offer for a fee,they will replace the board for one more resistant to heat,but temperature was Not the problem,according to them,since then ,I install in the cover a fan with temperature control,always on,never again the problem.
Hugo
 
Glad you made it back on the ground with no further issues. I do not have any experience with the electronic ignition but others seem to have a probable cause.

Good news is if it was the EI at least you know that it will fly on one. With the number of failures noted just by RV's on the EI, I guess I am glad I stuck with the 50 year old mags...

Smilin' Jack
 
I'm trouble shooting it as we speak.

I spoke with Klaus this morning and he said that his EI is extremely well protected against spike voltages and that it can operate down to 5 volts? I had 11.4 when I landed and the alternator has been taken to a local Mennonite repairman. It may well be the mag. We shall see.

The battery is being trickle-charged and I'll know more when the alternator is re-installed.

Best,
 
I recall having a conversation about low-dropout voltage regulators with Paul Lipps (designer of the Lightspeed ignition), and he told me the Lightspeed ignitions will run down close to 5V.

Funny that I also have a Mennonite friend who works on alternators and starters :)
 
After a bout with some ignition issues (self induced), I am now in the habit of performing an enroute "mag check" in addition to the normal end of runway runup. As discussed on this site and elsewhere, the enroute check (LOP in my case) provides a far better indicator of ignition health than the nearly worthless end of runway check we've been doing for decades. That said, any uniform change in EGT should have included this check as the initial troubleshooting step. Be aware however, that if we are right and you have a dead ignition, the engine would go very quiet when you isolate L and R. Be over an airport or at least be ready for it!
 
...With the number of failures noted just by RV's on the EI, I guess I am glad I stuck with the 50 year old mags...

...and it is the number of mag failures on all GA aircraft that drove me to to dump the ancient technology in favor of the EI. ;)
 
Yep

...and it is the number of mag failures on all GA aircraft that drove me to to dump the ancient technology in favor of the EI. ;)

Exactly. With 6 years and 550 hours of use, plus incredibly fast hot starts, the Lightspeed system has been totally trouble-free. I watched a British Bulldog trying to get started for an hour on Saturday and mine fired up with 11.7 volts showing, instantly. Klaus's E.I. is one hot mama....so much so that you have to use his ignition leads...shielded aircraft leads won't cut it.

Best,
 
I had a similar problem in my -4

A couple of weeks ago, I was flying along happily and then noticed my (one channel) EGT reporting 1400+ temperatures. Fuel flow was very high (12+ gpm), but power was low. Throttle or mixture adjustments made everything worse.

I made a precautionary landing at the nearest airport and removed the cowl to look. I found 2 loose fuel injectors! The body of one injector was loose and the B-nut on another was loose. Both were dumping fuel into the cowl as evidenced by large blue stains.

I left the plane with the local FBO and asked them to remove, inspect, and replace all the injectors and review the fuel system. One the injectors were re-torqued, everything worked well again. I have made a few (local) flights since and, so far, everything is behaving beautifully.

Your problem sounds a little more complicated, and every bit as scary.

Good luck,
 
Pierre, I do not know about hot start issues, we run two mags and they start first go all the time, and as you would appreciate, we are not in a cold climate here. 95 degrees F yesterday, and it is only spring!

Back to what you experienced, when one mag/EI goes off line you get a rise in EGT, and a slightly lower CHT. The reason for the higher EGT is due to less expansion of the gasses as the peak pressure is now occurring further from TDC than before thus has more volume and lower pressure. Same reason why a lower compression engine runs a higher EGT.

There was no reason to change the F/A ratio at all, in fact by going richer the only thing you did was reduce HP, waste fuel, gunk up the engine etc.

Toolbuilder is correct in saying the best mag check you can do is one done in the cruise LOP at the highest power you can attain (WOT/2300-2500/LOP) and best to do it near TOD, so that you have some trouble shooting time in flight before you land.

As for being above an airfield, I disagree, but if it makes you feel warm and fuzzy the first couple of times sure go ahead. If you have a dead mag, the engine flames out, remember this! If you are pumping fuel and air into the exhaust and you were running ROP, their is a good chance you will have a nice "after fire" mixture in the exhaust. So pull the mixture to idle cut off, go back to the good mag, and slowly sweep the mixture back in. Engine relights and away you go knowing you have one mag to fix.

If running LOP there is not much chance of harming anything, you might get a few rumbles but there is nowhere near the fuel available in an expanding volume of space to cause a major event.

Have a look at a good mag check in flight, WOT and LOP at FL130, this is no doubt the kind of result you saw.

http://www.youtube.com/watch?v=s155lSZxsKQ

By the way, you really would learn a heap and undo all those old habits of what we were once taught with a weekend holiday in Ada OK. Yeah I know it is not a tourists bucket list entry but for piston pilots it has one gem.

Be keen to know the outcome too Pierre, be it EI or mag. Just also go looking at the P leads and make sure that one is not being grounded, that shuts em down pretty effectively too!
 
As always a nice video and education for those of us who have not flown piston engines in a while.

I know that a lot of folks are sold on EI and perhaps some day we will move that direction. But I got to get it flying and when we were building the engine EI were going to increase the cost more.. We did go the GAMi injectors which most folks really rave about.
Thanks for video David

Jack
 
It was caused by the fact that Pierre was a good guy and didn't race this year (he usually wins!), letting me post the fastest time overall. No good deed goes unpunished!


Lee...
 
SO...way to leave us hanging.....what was your speed and did it meet your expectations. Details man, we need details!;)
 
...As for being above an airfield, I disagree, but if it makes you feel warm and fuzzy the first couple of times sure go ahead...

Yes, it is more for my wife than anything... I'll also switch tanks within gliding distance of a suitable landing spot if I have the choice. With the routine mag check, I always have the choice.
 
Pmags

Y'know, I was limpimg home with only 11.5 volts showing and it may well have been the Lightspeed failing,,,hmmmmm? Yep, it was also accompanied by a loss of several MPH, but I thought that the Lightspeed only needed aroun 9 volts, no?

Yep....could be.

Thanks,

Pierre,
If it turns out that the Lightspeed failed, I recommend that you switch to an EI system that operates independent of the aircraft's electrical system except for starting. Pmags!
 
Pierre,
If it turns out that the Lightspeed failed, I recommend that you switch to an EI system that operates independent of the aircraft's electrical system except for starting. Pmags!

That may be very hard for him to do. He flys a 6 cylinder Lycoming. There aint no Pmag for that! :)
 
Apologies for the thread heist: I won (the trophy for Fastest Around the Course!) but with only a 215 mph average over a 127.2 nm round-robin course. Modest winds, CHT's and EGT's no problem, but oil temp...uh oh. When it got to 225F, I pulled it back a bit and it stopped and stabilized there. Was bouncing around indicating 212 kias at full power prior to that but only about 192-195 kias with it throttled back from the 31.2" it was indicating, to about 29.0"-29.5" for probably 95% of the race. Seemed like a big drop in speed for so small a reduction, but what do I know? Prior to the "pull-back", my EDM 900 was showing 100% power, after the pull-back, only 95%-96%.

Ran full rich and with the prop at 2,650 (that seems to be where the stop is set). Next time I will try trimming slightly to different prop settings---this time I was too busy watching for kamikazi buzzards and towers (I ran relatively low). Anyway, sorry for all the jabber, sure was fun. I ran down 3 or 4 aircraft in front of me (no classes in our race, handicaps only).

Anyway, I sure appreciate all the advice I got here on the VAF forum. It really did seem like the engine was very happy running hard. May have to figure out a way to cool the oil down a bit though if I do that any more, though.

Thanks again to Pierre for letting me win my first race!


Lee...
 
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That may be very hard for him to do. He flys a 6 cylinder Lycoming. There aint no Pmag for that! :)

Any day now...

When I spoke to Emag a few weeks ago they were ramping up production of their six cylinder P-mags.

I hope they are as successful as the four cylinder P-mags!
 
Great.

FWIW...I last raced the R2R in 2011 and the same course took me right at 45 minutes. Lee ran it around 40 minutes!

He could get 243 MPH (212 knots) to my 217 in the -10. I beat a retractable Lancair with an O-360 because I climbed to 1200' to take advantage of a strong 30 knot tailwind on the longest leg to the finish line. He stayed under the broken overcast and circled one turnpoint three times, trying to see the field, while I relied on my pre-programmed flight plan in the 430W to control the flight to my autopilot. :)

...all's fair in love and war :)

Best,
 
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