Special Tool 9187 and Air/Fuel Adjustment
08-20-2004, 12:43 AM
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Special Tool 9187 and Air/Fuel Adjustment
I have been thinking about the historic posts here on gas mileage and decided that I am likely running a bit rich. I first suspected this when I was looking for the source of a high idle. After fixing that by doing the standard stuff and finally just turning down the idle screw (which was the problem all along 
) I began to suspect that maybe someone cranked the idle to get it through smog because they weren't able to figure out how to adjust the mixture.
Enter special tool 9187:
Take one old tent pole, a 3mm allen wrench slightly modified, an old axe handle and some JB Weld and presto.
So on to the adjustment. I bought an AFM that I can unplug (So that I don't barf from watching the LEDs cruise back and forth) and I want to check my technique before making the adjustment.
From what I can tell the best way to do this without a real CO sensor is to make a small adjustment and check the AFM at WOT and repeat until you get it right. The AFM company suggests that you should light the 2nd to last LED under those conditions. Right now all light up. It appears that the trick is to make sure it is not too lean so you don't get detonation.
Anybody BTDT? Any hints, warnings, blessings, or invocations?
TIA
) I began to suspect that maybe someone cranked the idle to get it through smog because they weren't able to figure out how to adjust the mixture.Enter special tool 9187:
Take one old tent pole, a 3mm allen wrench slightly modified, an old axe handle and some JB Weld and presto.
So on to the adjustment. I bought an AFM that I can unplug (So that I don't barf from watching the LEDs cruise back and forth) and I want to check my technique before making the adjustment.
From what I can tell the best way to do this without a real CO sensor is to make a small adjustment and check the AFM at WOT and repeat until you get it right. The AFM company suggests that you should light the 2nd to last LED under those conditions. Right now all light up. It appears that the trick is to make sure it is not too lean so you don't get detonation.
Anybody BTDT? Any hints, warnings, blessings, or invocations?
TIA
08-20-2004, 10:52 AM
#3
Rennlist Member
Marc,
You're far too professional in your design and execution!
- this makes the rest of our homemade tools look pretty shabby 
.
The one in the center of the pic below is a crude version of your design that has served for years - a 3mm hex tapped into a piece of brake line tube with a right angle indicator on the 'turning'end ( when adjusting near the limit, a 1/4 turn can be a lot).
Awaiting design improvements, the rest of the junk( starting clockwise top ) are two sucker sticks that slide within a band of masking tape = suspension height gauge with mm measure, little bars on stovebolts = 4 piston caliper pad spreaders, 27mm crows foot for counter holding rad connectors and removal of oil pressure sensors, 1/4" plate hook wrench for spring adjusters, and Al plate bits to allow a flywheel lock to be used in both 16v/32v cars.
Maybe others have homemade bits they would like to turn over to your new design studio.
On the matter of adjusting, I initially tried unplugging the O2 sensor and connecting to a Fluke multimeter: hot engine/exh, and target ~0.5v: The downfall of that is that the ECU is now in open loop but I got 'close'. Then with the sensor reconnected, I progressively leaned the mixture out over a few days of driving until it would begin to 'hunt' at ~ in town cruise speeds: This was the edge of being too lean, so I enriched 1/4 turn - and it runs fine.
I'm not too satisfied with this approach, but I'm eager to hear of a better one. Good luck in finding the stoichiometric point - and in tool design!
You're far too professional in your design and execution!
- this makes the rest of our homemade tools look pretty shabby .The one in the center of the pic below is a crude version of your design that has served for years - a 3mm hex tapped into a piece of brake line tube with a right angle indicator on the 'turning'end ( when adjusting near the limit, a 1/4 turn can be a lot).
Awaiting design improvements, the rest of the junk( starting clockwise top ) are two sucker sticks that slide within a band of masking tape = suspension height gauge with mm measure, little bars on stovebolts = 4 piston caliper pad spreaders, 27mm crows foot for counter holding rad connectors and removal of oil pressure sensors, 1/4" plate hook wrench for spring adjusters, and Al plate bits to allow a flywheel lock to be used in both 16v/32v cars.
Maybe others have homemade bits they would like to turn over to your new design studio.
On the matter of adjusting, I initially tried unplugging the O2 sensor and connecting to a Fluke multimeter: hot engine/exh, and target ~0.5v: The downfall of that is that the ECU is now in open loop but I got 'close'. Then with the sensor reconnected, I progressively leaned the mixture out over a few days of driving until it would begin to 'hunt' at ~ in town cruise speeds: This was the edge of being too lean, so I enriched 1/4 turn - and it runs fine.
I'm not too satisfied with this approach, but I'm eager to hear of a better one. Good luck in finding the stoichiometric point - and in tool design!
