View Single Post
Alan L Alan L is offline
Registered User
Alan L's Avatar
Join Date: Apr 2006
Location: New Zealand
Posts: 3,249
Here is how I do it. Get 6 smallish clean containers - enough to hold 100-200 mls. Need small - bit of a squeeze in places. Unhook your injectors and remove from inlet blocks. Hook injectors back on fuel line. Place container under each injector. (you will pronbaly need to remove some of the induction system - particularly LHS) to get enough room to fiddle. Turn key on. Depress airplate. Injectors will whine/flow.Open plate at least half way to get decent flow. After 15-30sec you will have collected about 50cc in each collector. The time is not critical - just measuring against each other. But need enough to get accurate measure.
Remove cups one by one. Pour into measuring container that can measure to 1 ml.
Record. Say you get from #1 to #6 (These are actual flows I measured a few days ago) 27, 30, 28, 29, 28, 31 cc. You can see 27 (#1) is lowest (leanest) . #6 richest. So you can even them up a lot just by adjusting #1 up and # 6 down. Take the caps of fuel head for #1 and #6. Insert allen key (3 mm I think). Lightly turn/feel for engagement in bottom of hole. Turn about 1/4 turn appropriate way.
Empty fuel jars and start again. The more fuel you collect in a run, the more precise your readings (less error).
After a couple of hours - here si my final run; 65, 64, 64, 63, 65, 64.
The numbers are bigger just because I ran for longer (maybe 30 sec instead of 15).
But it is a variance of 2/64 = about 3%
If I fiddled longer, could do even better.
If 10% variance (+/-5%), at AFR of 12, you have one cylinder at 12.6 If 12.5 is the critical safe point (as many would suggest - hence run at 12), don't be surprised if you melt a piston even tho you were running at your 'safe' AFR of 12.
Old 04-09-2008, 08:47 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #11 (permalink)