RPM fluctuation on idle and engine choking

Any DA40 related topics

Moderators: Rick, Lance Murray

User avatar
yl472401
3 Diamonds Member
3 Diamonds Member
FIRST NAME: Bryan
Aircraft: DA40
Registration: N890US
Airport: 1C5

Posts: 151
Joined: Sat May 16, 2020 5:02 pm
Has thanked: 51 times
Been thanked: 13 times

Re: RPM fluctuation on idle and engine choking

Post by yl472401 »

Roxi5m9 wrote:
Rich wrote:
Wed Aug 05, 2020 6:09 pm
The video won't play for me. But an EGT rise on a cylinder accompanying the RPM drop would indicate a plug misfiring. An EGT rise on all cylinders suggests a mag problem or p-lead intermittent short.
That’s not necessarily true from my experience, Rich. This last spring we noticed some intermittent engine roughness. After a lot of troubleshooting and doing an inflight mag test we figured out the number 2 cylinder on the right mag was intermittently misfiring. We replaced the plug, no help, replaced the harness, no help, realized we had 900 hours on the mags, replaced them, fixed it. Basically, somewhere in the core of the mag it was wore out. From what I was told, usually a mag will impact all cylinders but not always.
Thanks for the heads-up. Will keep an eye out on the issue.


Sent from my iPhone using Tapatalk
User avatar
Karl
4 Diamonds Member
4 Diamonds Member
FIRST NAME: Karl
Aircraft: DA40

Posts: 211
Joined: Wed Aug 04, 2010 3:58 am
Has thanked: 43 times
Been thanked: 46 times

Re: RPM fluctuation on idle and engine choking

Post by Karl »

Before you spend too much money or adjust anything get the exhaust and induction gaskets checked to see if they are leaking. Either could cause this problem especially the induction gaskets. Probably best to just change the induction gaskets as they are very cheap anyway.
User avatar
yl472401
3 Diamonds Member
3 Diamonds Member
FIRST NAME: Bryan
Aircraft: DA40
Registration: N890US
Airport: 1C5

Posts: 151
Joined: Sat May 16, 2020 5:02 pm
Has thanked: 51 times
Been thanked: 13 times

Re: RPM fluctuation on idle and engine choking

Post by yl472401 »

Karl wrote:Before you spend too much money or adjust anything get the exhaust and induction gaskets checked to see if they are leaking. Either could cause this problem especially the induction gaskets. Probably best to just change the induction gaskets as they are very cheap anyway.
Thanks Karl,
The issue got fixed with the fuel servo and a few other parts replaced. Costed an arm Image


Sent from my iPhone using Tapatalk
Post Reply