Fuel injection "loping"

damon · #1 07-13-2009, 12:40 PM

I've recently installed a Precision Silver Hawk fuel injection system on my O-360 RV6.
When the engine is hot and at idle (like during rollout and taxi) it will oscillate 100-200 rpm. Never in danger of quitting but not right. Electric pump on or off. Pressures 25+psi. Idle set at 800 rpm. Idle mix is correct. No obvious air leaks. Precision says: "May be vaporizing fuel" and "Sometimes they'll do that" Hmmm.
Any ideas?

Kahuna · #2 07-13-2009, 12:43 PM

"Sometimes they'll do that"
And a lot worse!

Welcome to fuel injection.
Nothing to worry about if this is your only symptom.

Bill Wightman · #3 07-13-2009, 01:05 PM

Not uncommon. Should run smoothly when off-idle, though.

DanH · #4 07-13-2009, 01:08 PM

At idle, pressure at the nozzles (not to be confused with the 25 psi to the throttle body) is very low. Delivery can be something akin to a fellow with a prostate problem.

frankh · #5 07-13-2009, 01:10 PM

This is NOT vapour lock (as some are used to calling it) and as long as it only happens at idle its fine.

Frank

David-aviator · #6 07-13-2009, 02:31 PM

Mine does it only after a hot start.

On taxi in it is a smooth as taxi out.