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Engine Driven Fuel Pump


Mike A

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So I need some more help on the mechanical fuel pump.  We ended up buying a rebuilt one from TCM, installed it, set it up and it worked fine in its ground checks.  We then replaced the alternator (voltage problem), and I finally got it back last week.  We ground tested the system, then took it up for flight work.  The mechanical pump worked fine for that 2 hr flight, with no issues at low RPM.  Last Friday we went to take the plane on a short hop, and the low RPM cutoff problem resurfaced.  I just got back from doing some tests and this is what I found:

 

1) Below about 1000 RPM, the engine will not stay on with only the mechanical pump

2) With the plane on the low boost and setup for 1200 RPM, turning the low boost pump off yields an increase of close to 200 RPM and the engine is operational

3) With the plane on the mechanical pump at about 1100 RPM, moving the mixture back towards cutoff there is no RPM rise, only the dropoff

 

This leads me to believe that the low RPM settings are too lean/low.  Does that sound right to anyone else?  Also, is there a good way to setup the system without having actual fuel flows.  The factory FF transducer is no longer operational and the engine management system has not been installed yet.

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I have very little experience with TCM/CMI engines, but I suspect your shop is not intimately familiar with the FI setup requirements.  From what I've read over the years, it is very finicky and difficult to get right.  Attached are some files I've collected from an acquaintance that owns a 33 Bonanza and does a lot of owner-assist maintenance, and has even written a book on the subject.  He helped a fellow Mooney K owner get his engine setup correctly in Denver a few a years ago after several attempts at a shop failed to get it right.  You should read these documents and become more involved with your shop to see if they really know what they're doing.

 

Another friend locally is having similar problems with his Rocket too.

FuelFlowSID97-3E-Notes.doc

FuelFlowSID97-3E-Turbo-Notes.doc

Continental_Fuel_Injection.pdf

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31 minutes ago, Mike A said:

My problems were hard to start cold and required the boost pump to be running until it got warm. It was diagnosed by a Mooney specific mechanic who had seen it before. 

Ok thanks for the clarification. I’m having surging but only LOP. Crazy thing was it was running fine until i had to pull the governor to get the AD complied with. While we were reinstalling the governor the A&P noticed the oil breather line was being supported by the #2 fuel injector line which i found out is a no no. We did a fuel leak check and to his surprise it was not leaking but the #3 injector line was. So he tighten that one and i was excited because i remember a few flights back i had a high reading on number 3 and i thought it was a fouled spark plug. So today’s test flight to verify the governor install was a mixed bag. The governor seemed to work fine and no oil leaks but now with that fixed number 3 injector i can not run LOP without surging. Tried a lean mag check and there was notable missing on both left and right check where as before it was smooth. A rich mag check is smooth no issues with the normal drop. I’m going to pull the engine data tonight to try and review to make some since of all this and post it here tomorrow but as right now I’m baffled. I thought induction leak but if i set 29 inches that’s close to atmospheric so it shouldn’t matter if there is a boost leak but then on the ground remembered i was at 3500ft so was still boosting over atmospheric by a couple of inches. I’ll pull the top cowl tomorrow and do another injector test to make sure there is not another leak and check all hose couplings to make sure one is not loose. Is there a way to check for induction leaks easily if i find all the hose clamps are tight and nothing is loose?

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On 2/24/2021 at 10:41 PM, carusoam said:

Will,

got any engine monitor data for that?

People link JPI data around here all the time...

Best regards,

-a-

Sorry been taking care of the family and kids just now got over to the hanger to download the data and upload it into savy.  Here is the link:

https://apps.savvyaviation.com/flights/4739209/1104bef0-3186-4502-94e5-2082c9e5ebc6

I think that will work?

Savvy doesn't show any abnormal indications.  The sharp drop off toward the end was when I was taxiing off the runway the engine died.  Once again I always lean out the engine on landing roll out and it hasn't done this before but this time had to rich it up a bit to keep it running.

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Zipping through the data for the one flight showing...

All the EGTs are pretty close together... CHT2 seems to be chilly for some reason... similar to CHT1

The EGTs on the different Mags on the run-up are showing peak Ts to be about 100°F different from each other... often a sign of a variation in Mag timing...

There is a way to share all of your flights...

That will include your LOP mag tests in flight...

If I don’t push the mixture in prior to landing... the engine will be stopped during the roll-out...   :)

Could be a mag timing issue... could be a fuel system set-up issue...

PP thoughts only, not a mechanic...

-a-

D4163C7F-952A-44FD-B8B9-C90FD175013F.png

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38 minutes ago, carusoam said:

Zipping through the data for the one flight showing...

All the EGTs are pretty close together... CHT2 seems to be chilly for some reason... similar to CHT1

The EGTs on the different Mags on the run-up are showing peak Ts to be about 100°F different from each other... often a sign of a variation in Mag timing...

There is a way to share all of your flights...

That will include your LOP mag tests in flight...

If I don’t push the mixture in prior to landing... the engine will be stopped during the roll-out...   :)

Could be a mag timing issue... could be a fuel system set-up issue...

PP thoughts only, not a mechanic...

-a-

D4163C7F-952A-44FD-B8B9-C90FD175013F.png

Checked timing mags are within 1 degree of each other. How could changing the governor effect the fuel system?  Granted stopping the leak would help I would think but here I am asking questions. 
CHT #2 is the piggyback temp prob I think. Will double check that but it’s always been the coolest temp. 

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Will,

You definitely found something to chase there...

That is one plug, attached to one cylinder and the one mag being tested...

What spark plugs do you have..? (Log check...)

If champion, test their resistance...

If the other brand, check to see if the center electrode is still there...

PP thoughts only, not a mechanic...

In cruise, What TIT do you usually see or use?

This spark plug issue is probably independent of the gov...

Notice how few data points you have during the run-up..?  you might consider doing the run-up using time, not just an aural check...  it looks like it happened in a few seconds, which isn’t enough time for the JPI to collect enough data points...  it takes about 10-15 seconds on each mag to see all the temps rise evenly catch a few data points at the peak, for a good comparison...

The data is barely showing two independent peaks.  And, with good timing, it looks like the peak didn’t get captured...

Some JPIs get left on their 6sec interval...when 2secs is available... newer ones have a 1sec option...

Primary flight training doesn’t use engine monitors... so many of us use an old style of doing a run-up...

NA PP thoughts only not a turbo guy or mechanic...

Best regards,

-a-

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6 hours ago, carusoam said:

Will,

You definitely found something to chase there...

That is one plug, attached to one cylinder and the one mag being tested...

What spark plugs do you have..? (Log check...)

If champion, test their resistance...

If the other brand, check to see if the center electrode is still there...

PP thoughts only, not a mechanic...

In cruise, What TIT do you usually see or use?

This spark plug issue is probably independent of the gov...

Notice how few data points you have during the run-up..?  you might consider doing the run-up using time, not just an aural check...  it looks like it happened in a few seconds, which isn’t enough time for the JPI to collect enough data points...  it takes about 10-15 seconds on each mag to see all the temps rise evenly catch a few data points at the peak, for a good comparison...

The data is barely showing two independent peaks.  And, with good timing, it looks like the peak didn’t get captured...

Some JPIs get left on their 6sec interval...when 2secs is available... newer ones have a 1sec option...

Primary flight training doesn’t use engine monitors... so many of us use an old style of doing a run-up...

NA PP thoughts only not a turbo guy or mechanic...

Best regards,

-a-

I have the jpi set at 2 sec intervals. I installed fresh tempest fine wire spark plugs at last oil change. They only have 24 hours on them since new. I needed to get governor inspected before spring break so changed the oil since i needed to drain it to keep the mess down when removing the governor. Keep the ideas coming. Something will come up. 

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While doing a run up...

0) Switch to R...

1) watch the temps rise on the JPI.... they keep going up for a while....

2) watch 15 seconds go by....

3) change to both...

4) watch the temps recede...  enjoy the 15 seconds...

5) Switch to the L mag... same thing...  watch the temps rise. 15 seconds...

6) back to both...

You are looking for that one spark plug that made a mess in the graph you posted...

Don’t rush the mag check... at two second intervals, you barely captured a few data points that weren’t at peak yet...

With new tempest plugs... expect one has lost its center electrode...

Oddly, the missing electrode still kinda works... just not when stressed... like during a run-up...

From your existing JPI data... you should be able to tell exactly what plug to pull and look at....

There are wiring diagrams to follow around here... to know...

  • Switch position... the R mag is on left most click...
  • Which mag was running when the plug wasn’t working...
  • what cylinder was it...

From that knowledge... pull the plug and see what is going on?

See if you can Share more than one flight of data...

The data you circled covers exactly four seconds in time... 

What is the chance it is an ordinary occurrence, that just happened to occur during the four seconds you are looking at it?

The one plug played dead for four seconds... according to the pic of the data...

 

There is most likely a procedure to follow at savvy.com for executing a proper run-up...

There are other things that can cause this as well... lead beads growing in the lower spark plugs... oil soaking or carbon crusting over the lower spark plug...

Grab the existing data...

Determine exactly what plug it is...

Pull it and give it a good look-see....

Take a pic of it, something caused the anomaly...

If the plug is in perfect condition... the search expands upstream to wires, connectors and mag...

Look at other flight data... how did you get four seconds of a plug not working, and not notice it?

Bring this up with your mechanic...

PP thoughts and basic science only, not a mechanic...

Best regards,

-a-

 

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Is the temperature dive on EGT#3 on the right mag?

If you have these answers...

It is perfectly normal to ask your mechanic to look to see what is going on there...

I did not see the temp dive in the data file you shared...

Did that come from a different data set?

-a-

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Well thanks to the beechcraft forum they had a continental fuel injection install pdf that explained very nicely with pictures of how the turbocharged fuel injectors are assembled, thus allowing me to not only understand how to take them apart but also listed the o-ring and rubber washer i needed to order to replace them. Once i replaced them and tested again to verify i did not have any soap bubbles and that sealed the airleak. Also did another fuel pressure test and no leak! Finally!  Took it up for a test flight and it’s running smoother than when i bought it. Also TIT was lower in flight and i especially noticed at idle before shutdown as before i struggled to get the tit below 800 d F but now it was at 750 and pulling back on the throttle it dropped to below 700 at low idle! Also swapped bottom #5 spark plug with top #1 and top #3 spark plug with bottom #3 and the rough lean mag check moved from the  left mag to the right mag so i ordered a new tempest fine wire plug as one of those is faulty and i think it’s number 3 too as i noticed the  ceramic  Insulator looks like its in 2 pieces. Will have to post pictures when i get the new plug to replace it. Only 24 hours on all 12 plugs but guess that one was infant mortality. 

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