IO470 Idle Help

B

bbrens

Filing Flight Plan
Joined
Feb 3, 2017
Messages
3
Display Name
Display name:
bbrens
Our 182P has an IO470 (Peterson 260 STC). Having a heck of a time keeping it idling.

When cool/cold engine the boost pump has to be on low in order to keep at idle or it will die, like fuel starvation. When engine is warm it will idle fine without the use of low boost. I noticed today after some time warming up, it would idle without boost pump on, however when advancing past 1000 rpms it would then studder, needed boost pump again until it was past 1200 rpm. After the flight and while at full operating temps, I could run at all rpm range without boost pump. It seems this issue is consistently getting worse over time.

Mechanical fuel pump has been rebuilt I believe, but I would have to confirm on the logs. Looking for ideas or direction, last few annuals the mechanics cannot seem to nail down what the issue could be. At times the fuel pressure gauge would fluctuate in cruise.

I am flying tomorrow and will see if I can record some pressure readings on the gauge and report.
 
Welcome to POA!

Most of my engine knowledge comes from the automotive side. Probably a vacuum leak somewhere. But a real expert should be by to help you soon.

I have been looking for Petersen conversion as of late, but they are hard to find. Where are you based?
 
First of all, based on your comments I would encourage you to stay on the ground until you identify and correct the root cause of the fuel flow problem. This seems especially prudent based on your statement that "... this issue is consistently getting worse over time." Be aware that your boost pump alone will likely not support full power operation of your engine, so don't use it as a crutch. Fix the problem.

Now, that being said here are my suggestions about the troubleshooting you need to do. BTW, I fly behind an IO-470 and it has a reputation of being a very reliable system (not perfect!). The TCM is a simple fuel injection system. AvWeb has a good article explaining its operation here:
http://www.avweb.com/news/maint/181624-1.html
The problem might be with your mechanical fuel pump, specifically in the relief valve. Take a look at the attached article. In particular note the explanation on page 2 which says in part "In the fuel pump, debris lodged under the seat of the relief valve results in a loss of pump pressure." This might lead you to the source of the problem. Good luck and keep us posted!
 

Attachments

  • ContinuousFlow.pdf
    120.4 KB · Views: 14
I am located outside of Hutchinson, KS and about 100 miles from Peterson's facility. The 260se is a great flying machine. Ours is an early version with no frills. Peterson makes some real showplanes out of these, ours needs a bit of refurbishment to get close to anything he puts out of the shop. It is actually owned by my dad and doesn't fly hardly at all. My family needs are expanding from 2 to 3 seats very soon so I expect this plane to increase in use hopefully.

I will pass that info along to the A&Ps that work on this airplane. I am going to do a ground run today to see how the plane behaves. The shop we use is actually a preferred shop by Todd Peterson as well.
 
Last edited:
Todd is a pretty neat guy and he has come up with some great designs and STCs. Got lunch with him once and listened to some good stories.

My guess would still be the fuel pump/relief valve as well. Seems most likely. Just because something was rebuilt doesn't mean it is perfect. I've seen a lot of rebuilt parts fail quickly. Might be worth checking your fuel strainer to see if you have any junk stuck to the screen.
 
Made a consult with local A&P. I mentioned the relief valve and induction leak possibility, etc... but he is absolutely certain in his mind it is an issue with the flow divider (sticking valve), since the problem goes away with full operating temps. Will probably send that off to be rebuilt, and will look over induction system and vacuum systems. Hope to do that in a few weeks and will report back on the finding or fix.
 
If the problem is primarily when it is hot, check the idle mixture setting (this is unaffected by the red knob).
 
Does anybody have a download link to the latest version of the TCM spec, SID97-3G. Not sure what the difference is between the "F" revision (which I have) and the "G" revision, but I am getting ready to setup a new fuel pump and I would like to have the latest spec. Thanks!
 
Rob58 said:
Does anybody have a download link to the latest version of the TCM spec, SID97-3G. Not sure what the difference is between the "F" revision (which I have) and the "G" revision, but I am getting ready to setup a new fuel pump and I would like to have the latest spec. Thanks!
Click to expand...

Continental has merged most of its long-running SBs into its Standard Practices Manual, M-0, here:

http://www.continentalmotors.aero/support/maintenance-manuals.aspx

Click on M-0, download the manual, go to sections 6-4.7 and 6-4.10.
 
Thanks - downloaded. Seems like a lot of things have changed at TCM.
 
You must log in or register to reply here.
Back
Top