Cold Start Help

[Marcopolo]

 

59 minutes ago, mccdeuce said:

 

Well took it into the shop today.  Not at all what I was expecting.  Will try and fly her tomorrow to verify everything is good.

Apparently the plugs were gaped really tightly and at least 2 of them were not working right.  They were champion plugs that the carbon had also failed.  All 8 have been replaced by Tempest plugs.

The mag timing was also off - mostly for the IC though.

 

In my opinion...and its a very vague opinion, nothing in this follow-up would explain what was showing in the data from the engine monitor.  Nor would it explain a change in the starting capabilities.  The plug gaps don't move, at least not at a noticable rate, and if they do its generally to wider, not narrower.

 

I'm not convinced, but my mind can be changed!

 

Ron

[mccdeuce]

I will try and post exactly what was done tomorrow. 

I am planning to put the EIS in so I decided to wait for that to switch to fine wire plugs. I also don't really know the difference. Other than they are "better"

planning to fix CHT 1 when I do the 830 swap. 

[Bob_Belville]

1 hour ago, mccdeuce said:

I will try and post exactly what was done tomorrow. 

I am planning to put the EIS in so I decided to wait for that to switch to fine wire plugs. I also don't really know the difference. Other than they are "better"

planning to fix CHT 1 when I do the 830 swap. 

There's a thread or 3 here with quite a few testimonials re fine wire Tempests. I think it is a fact that the only folks who do not think they're worth the difference in cost have not flown with them.

[mccdeuce]

Found left magneto impulsing 5d past TDC.  Bottom spark plugs on cylinders 2 &4 not firing.  Found electrodes bridged and electrode gap too tight.  Removed all spark plugs and found all gaps too tight.  Performed resistance check on all plugs and found all to be mega-ohm range.  Installed eight new spark plugs UREM38E. Adjusted internal timing e-gap.  Timed left mag to 20d BTDC.

Results - she starts cleanly.  Still think she is burning hot though.  More investigation to be had.

https://www.savvyanalysis.com/flight/1652550/bdf430bc-33e9-446f-964e-08152701a837

[DVA]

I'm going out on a limb here. I'm not convinced you've the problem that caused the oddities in the trace on that flight I pointed out. You may have found problems, which is great! But I still think you'll have a hard start issue and more flights with odd egts because the wiggling of the ignition key on the mag check, and that trace, is not s result of timing and a few bad plugs.

Out of an abundance of caution I hope I'm wrong.

Best regards,
Dave


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[mccdeuce]

Dave - I don't disagree with you at all. The key is not the original and I am planning to put the ElectroAir switch panel in.  I like the cleanliness and simplicity. The engine started extremely well today and I will continue to monitor the egt/RPM as I troubleshoot. 

As for the high CHT I am looking at the baffling. The seals look good but found a spot where I would say there should be a plug. 

[Guest]

On December 1, 2016 at 9:23 PM, mccdeuce said:

Dave - I don't disagree with you at all. The key is not the original and I am planning to put the ElectroAir switch panel in.  I like the cleanliness and simplicity. The engine started extremely well today and I will continue to monitor the egt/RPM as I troubleshoot. 

As for the high CHT I am looking at the baffling. The seals look good but found a spot where I would say there should be a plug. 

For your J model there should be 6 ignition wires passing through that grommet, the uppers for cylinder 2&4 and all the wires for 1&3 and then some sealant for the remaining gap.

Clarence

[mccdeuce]

I'm assuming that this was changed because of the split mags. I have a a3b6 - so I will try to get a better grommet for just 2 wires. 

[Guest]

9 hours ago, mccdeuce said:

I'm assuming that this was changed because of the split mags. I have a a3b6 - so I will try to get a better grommet for just 2 wires. 

That would explain it.  Then you need one of these:

http://www.aircraftspruce.ca/catalog/eppages/enginebafflem2375.php?clickkey=3040640

Clarence

[mccdeuce]

So I have the Slick Ign Wire baffle seal installed and took her for a test flight.  Somewhat biased of results based on outside temperature being 15deg colder.  Got about a 20deg cooler temps.  So maybe just maybe I am getting 5deg from the seal.  However I am not really convinced.  I think the baffle seals themselves prob need to be replaced and I will order from GeeBee.

Going back to what was pointed out earlier though - still not comfortable with the RPM fluctuations.  Engine seems to be running smooth.  Could it be the Prop governor? I would say no because there are also EGT and CHT fluctuations to match. 

The switch is high on my list of things to change out. 

[carusoam]

What are the rpm fluctuations? + and - 10 on the digital rpm indicator?

What is the accuracy of the rpm gauge?  Does it use the ones column, or decimals.  Or is it limited to 10s?

It appears the accuracy of the sensor may be looking like the rpm is all over the place....

Compare that to a smart phone graph of rpm using engine sounds.

There does look like two areas on the JPI graph that are noisy like the data isn't being delivered very well...

In that case look for loose connections between the rpm sensor and JPI.

When was the last time the gov saw an OH?  The fly-weights have a tendency to wear out their guides.  This can cause some fluctuations in their ability to control rpm...  possibly a good candidate to Iran vs OH...(?)

PP advice only, not a mechanic...

Best regards,

-a-

[kevinw]

I'm still wondering if the engine is running too lean. Did you try increasing the mixture to see if the temps reduce?


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[mccdeuce]

I will try that tomorrow.  Running at 10+gph at 6500ft.  

Also weird one today was a fuel smell when leaning LOP.  (was trying that versus ROP)

I also think I need to run a GAMI test to evaluate the engine - but was hoping to do that after getting my 830 installed/fixing CHT#3 and integrating the fuel flow and MAP.  (everything is else is already installed on the 700)

[Bob_Belville]

47 minutes ago, mccdeuce said:

I will try that tomorrow.  Running at 10+gph at 6500ft.  

Also weird one today was a fuel smell when leaning LOP.  (was trying that versus ROP)

I also think I need to run a GAMI test to evaluate the engine - but was hoping to do that after getting my 830 installed/fixing CHT#3 and integrating the fuel flow and MAP.  (everything is else is already installed on the 700)

What RPM were you running @ 6500? Full throttle should have given you close to 24" so unless you pulled the prop back under 2400 you were running over 70% HP. At 65% or below, you cannot cloose any mixture that does the engine any harm but to run LOP at 75% you really need to have an EDM and understand what you're doing. (LOP, %HP= 15/engine HP. For our 200 HP Lyc. that means 65% is 8.7 GPH and 75% is 10 GPH.)

 

[mccdeuce]

I was running 24" MP if I remember correctly at 2500 rpm.  I am using an EDM - its a 700 series with some but not all options to take it to the 800.  Am upgrading to the 830 and will add the last 2 options when that finally comes from JPI.  My fuel flow is also not linked to the EDM its a separate Shadin miniflo.

[carusoam]

Two things going on...

one is the discussion of the red box or red fin... a place to avoid engine ops to avoid accidental damage... the red box ends at 65% hp...An MP that can't be exceeded by an NA engine above about 8.5 k' (?)

release of fuel in flight... take a look at your fuel injectors, they have a vent hole in the side...  fuel shouldn't be coming out of them, but they may not be oriented properly or something else may be going on...  look for blue stains coming out of one of them...

PP ideas, not a mechanic...

Best regards,

-a-

[Bob_Belville]

9 hours ago, mccdeuce said:

I was running 24" MP if I remember correctly at 2500 rpm.  I am using an EDM - its a 700 series with some but not all options to take it to the 800.  Am upgrading to the 830 and will add the last 2 options when that finally comes from JPI.  My fuel flow is also not linked to the EDM its a separate Shadin miniflo.

Interpolating my Es 5000' and 7500' power settings pages, your 24/2500 is probably 75% or a little more. The combined "49" confirms that. To stay out of the red zone at 75% power you want to be ~100 ROP (probably 11+ GPH) or do a "big pull" and get safely on the LOP side - perhaps 9 GPH.

Are you familiar with John Deakin's Pelican Perch? Lot's of great, free, info here:

http://www.avweb.com/news/pelican/182146-1.html

This overview might be a place to start, but there are more detailed articles explaining the red zone in particular and leaning in general: 

http://www.avweb.com/news/pelican/Pelicans-Perch-19-Putting-It-All-Together-182085-1.html

[jlunseth]

I have a Conti and a different start procedure so I can't help with that, but two things.  First, I love in MN and we get lots of cold start practice.  Anything under 40 dF means plugging in the heater, and that is what we do regardless of the engine make.  Yes you can start the engine at 20 but it is too hard on the batt and starter.  Second, on my Conti, if the engine catches but won't keep running I give the high boost a touch which improves the fuel flow until the engine driven pump has full prime. Works well for me.

Edited December 17, 2016 by jlunseth

[DonMuncy]

On my TSIO 360 Continental, if it won't run, it needs more fuel. I'm sure it can probably be flooded, but I have never seen it. My standard procedure is; throttle full, mixture rich, High boost for 5 or 6 seconds, then primer for the number of seconds in the POH (on the heavy side). Hot weather 3-4 seconds, cool, 6-8, cold 10-12. Then throttle 1/4 inch, full rich and start. If it tries to die, more primer.

[markejackson02]

I couldn't start the plane Saturday.  The technique I used: throttle 1" open, full rich, boost on for three seconds then off, slowly reduce mixture to ICO.  Wait 10 seconds, crank.

Nada.  Tried to flood it, etc.  No love.  Even flooded technique didn't work.  Sooo, I went back to the POH.  I found the starting procedure to be different from the checklist. In short, I have found three different starting procedures in the various POH's.  I have a 1977 201 (S/N 48) with A3B6D.

My POH - throttle 1/4" open, mixture ICO, fuel tank selected, boost pump on until pressure > 10" then off, advance mixture to 50% for three seconds, then ICO, then crank.

Later POH - throttle 25%, mixture full rich, boost on until pressure rises, then off, mixture ICO, then crank.

Checklist - throttle 1", mixture full rich, boost on three seconds, then off, mixture ICO, then crank.

Why the differences?

Going to try the POH one this evening.  If that doesn't work, will have mx look at it.

[AH-1 Cobra Pilot]

4 hours ago, markejackson02 said:

My POH - throttle 1/4" open, mixture ICO, fuel tank selected, boost pump on until pressure > 10" then off, advance mixture to 50% for three seconds, then ICO, then crank.

Later POH - throttle 25%, mixture full rich, boost on until pressure rises, then off, mixture ICO, then crank.

Checklist - throttle 1", mixture full rich, boost on three seconds, then off, mixture ICO, then crank.

Why the differences?

There really is not that much difference between them.  I have inadvertently closed my throttle while 'priming', and apparently, the engine received no fuel.  I, therefore, suspect there is some connection to shutoff fuel flow via the boost pump when the throttle is closed.  Thus,  1/4", 1", 25%, does not make any difference.

It might take about three seconds to notice the fuel pressure rise, so not much difference there, either.

One technique I have used during starting is to engage the boost pump momentarily if I determine the engine is not getting enough fuel in order to fire.  Mostly, though, I have the hot engine troubles.  In that case, DO NOT prime with the boost pump, but open the throttle around half-way, crank, and gradually increase the mixture until the engine fires.

[jaylw314]

On ‎8‎/‎7‎/‎2017 at 0:09 PM, Ah-1 Cobra Pilot said:

There really is not that much difference between them.  I have inadvertently closed my throttle while 'priming', and apparently, the engine received no fuel.  I, therefore, suspect there is some connection to shutoff fuel flow via the boost pump when the throttle is closed.  Thus,  1/4", 1", 25%, does not make any difference.

It might take about three seconds to notice the fuel pressure rise, so not much difference there, either.

One technique I have used during starting is to engage the boost pump momentarily if I determine the engine is not getting enough fuel in order to fire.  Mostly, though, I have the hot engine troubles.  In that case, DO NOT prime with the boost pump, but open the throttle around half-way, crank, and gradually increase the mixture until the engine fires.

I'm not sure that's entirely correct.  IFRC, fuel flow to the injectors is metered by airflow, mixture setting AND throttle setting.  So more throttle on priming means more fuel.  On the other hand, if you don't move the throttle between priming and cranking, you will get more airflow in proportion, so the end result should be the same.