AOG four months now.

[flyer338]

28 minutes ago, PT20J said:

Precision Airmotive (current manufacturers of RSA fuel injection systems) has a DVD on troubleshooting that includes this test. Call them and they will send it to you free of charge. 
 
@flyer338 didn’t mention whether CHTs are higher now than with earlier higher fuel flows. Concern would be that if fuel flows are now too low, engine may be too lean at full power reducing detonation margin. 

Skip

Skip, I cannot comment on the CHTs, but examination of the spark plugs and bore scope examination of the combustion chambers did not reveal any signs of detonation. 

[flyer338]

3 hours ago, EricJ said:

IIRC, there's an SI or SB from Lycoming about using a clear piece of tubing between the servo and flow divider during a ground run to look for bubbles.

Thank you for that and I will pass it along to the shop. 

[Oldguy]

This may sound like a stupid question, but I excel at asking them.

Have you been using the same tank on all of your tests? Could the difference in static versus in motion be a symptom of fuel pickup problems in that tank, i.e. the pickup has gunk on the bottom of it and strangles fuel flow and the top is fine until fuel flows to the back of the tank?

Like I said, stupid questions, but, hey, I play to my strengths.

[carusoam]

I am hoping we get to see some engine data still....

Bubbles in the fuel line... often show up in wacky FF information as the bubbles get counted as if they are fuel...

A steady stream of bubbles will appear as higher FF than needed... or deliver less fuel than actually indicated...

The fuel selector valve is often a source for bubbles... got any blue stains near the selector handle?

 

So... the after fire... was probably caused by fuel escaping the cylinders unburned... hanging out in the muffler waiting to be ignited by something hot...

Typical causes of fuel escaping the cylinders unburnt...

• Bad spark... high resistance in plugs or wires.... or broken plugs
• delayed timing... a post of downloaded run-up data is good at showing a variation in timing between the two mags...
• Bad mag... weak spark being delivered to the cylinders...
• Dirty plugs, or lead beads...

If you have champion plugs, check their resistance... match to spec...

If you have the fine wires by the other company... check to see if the center electrode is still in place...

How lean can you taxi the engine around...?  FF during taxi?

 

Often people around here show pics of the spark plugs in the tray...

How many hours are on each of the mags..?

A regular mag often starts giving trouble some time after 500hrs...

electronic mags are interesting... not much experience to share yet.

PP thoughts only, not a mechanic...

Best regards,

-a-

[bradp]

A JPI download and upload to savvy cloud would be very very useful.  As would an in flight mag test and a baby bottle test.  

[flyer338]

It is time to update this thread - I am flying again, and as of three days ago my Mooney is at home in its new hangar after a four hour flight across the sierras. I will provide the details in another post. Part of the delay is that I was sick for two months, and there is no one in Eureka, CA qualified to test fly a M20J.

[flyer338]

I am not sure how to begin this missive. I will say that from the beginning all involved believe we had a fuel problem. That turns out not to have been the case.

I cannot fault the A&P IA involved, and I credit him with identifying the solution.

The problem was an intermittent failure of electronic ignition pick-up that replaced the right magneto. The failure only happened when the pick up was hot, and then only intermittently. Any intermittent problem is difficult to diagnose. The good news is that intermittent problems invariably get worse, and that helps in pinning them down.

A major obstacle in isolating the problem is that I was not doing the mag checks properly, and I did not isolate the electronic ignition as the source of the failure as soon as possible.

I am happy today that my plane is flying, I have confidence in the EIS-4100 electronic ignition, and I better understand and believe in the importance of knowing all of the systems cold. 

[carusoam]

Brian,

See Brad’s note above...

The coolest thing about collecting data from an engine monitor, porting it over to Savvy, sharing it, posting a link here....

People can see what you are doing... and give you insight on how to get to where you want to be....

 

Try it out... doesn’t cost any extra... do it before you need to share data...  this way you know it is collecting data properly...

Think how far back you could have been closer to a solution...

 

Many new MSers find out the engine run-up we do in primary flight training barely covers the bases...

PP thoughts only, not a CFI... or mechanic...

Best regards,

-a-

[jlunseth]

On 2/24/2020 at 11:39 PM, flyer338 said:

I have a JPI, but I am not savvy enough to perform a download.. I plan to call savvy in the morning. Better late than never.

There is a little sort of rectangular pyramid at the bottom of the device. It is a plug/cover for the download slot. Pull it out (put it in your pocket so it won’t get lost). Put a jump drive in that USB slot. Wait a moment. It will say “Download?” and below that, Yes and New. Might as well just hit Yes, either button would work though, don’t stress if you fat finger the other one. It will let you know when it is done. You can take the stick drive out, put that cover back on the USB port, take the stick drive home, plug it into the USB drive of your home computer, click on This PC. You will see at least a couple of drives, one will be an external drive. That is your jump drive with the downloaded files.  Click on the jump drive, it will be open and there are all your files. Savvy’s website will take it from there, or you can email files.

PS forgot to mention it won’t download with the engine running, mine won’t anyway. just get in the plane and turn the Master on. Does not take much time, I wouldn’t worry about the battery.

Edited July 27, 2020 by jlunseth