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Date: Sat, 27 May 2006 00:32:53 -0400
From: John Slade <sladerj@bellsouth.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Another case of heat-soaked coils?
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Just dumb luck really, Bob.
I wheeled the plane out this morning before starting on diagnosis. It 
ran up to 5300 as before, then started to spit and cough at higher rpms 
once it warmed up - so this was definitely a peripheral problem, not 
mechanical. Fuel pressure and mixture seemed constant and the symptoms 
felt too "sudden" to be fuel related. Coils have redundancy. Switching 
coils, ECUs and injectors made no difference. What is central to 
ignition? Hmmm. Crank angle sensor. I have the connections embedded in 
red silicone for corrosion protection. When checking under the cowl I 
touch everything. I pulled on each wire in turn. One came out of the 
silicone with very little resistance. I cleaned up the connection and 
resoldered it, then did more runups. No more spitting. There was no 
problem with the connectors themselves, but the pigtails were quiet 
short - probably insufficient strain relief.  Today I got new connectors 
today from Mazda MPV vans at the u-pull-it junk yard - this time with 
long pigtails. (the identical connector is used on the MPV for something 
on the left as you look under the hood.


Bob Darrah wrote:
> John,  Just how did you figure out it was the crank angle sensor 
> connector-what steared you in that direction? 
>  
> It's more efficient to learn from other peoples experiences.
>  
> Thanks
>  
>  
> Bob Darrah
>  
>  
>
> > Well it wasn't the coils after all.
> > Florida humidity had gotten to one of my crank angle sensor connectors.
> > Problem solved.