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Fiddling With the Air Flow Sensor...does this work? (digifant)

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Fiddling With the Air Flow Sensor
The common tweak of adjusting the idle mixture at the air flow sensor (AFS) to "cream up" throttle response. One tweak which is known to L-Jetronic tuners and that can work on the Digifant cars is to slightly loosen the spring tension on the air flow sensor.
By reducing the spring tension on the AFS you are essentially allowing more air to flow into the intake for a given throttle position. This "tricks" the computer into supplying more fuel at lower RPM, in effect richening the mixture throughout the range up to about 4,000 RPM when the AFS is wide open anyway.
Reducing AFS Spring Tension
To reduce the spring tension, first remove the black plastic cover on the air flow sensor by cutting up through the silicone sealer with a sharp blade. You will see, among other things, a black gear-wheel on top of what looks like a clock spring. A wire clip engages a tooth on the gear-wheel and is held in place by a 7 mm screw.
Scribe a permanent mark on the gear-wheel at the tooth where the wire clip engages (This is so you can go back to the stock setting if need be).
This is the tricky bit: Get a good grip on the gear wheel with your fingers. Loosen the 7 mm screw and wire clip assembly. Don't drop anything, and whatever you do, don't let go of that spring, or you may never get the car to run correctly again!
Now, carefully unwind the gear-wheel 3 teeth counter-clockwise. This is no more than 8 or 9 mm, so be careful. Reset the wire clip three teeth to the loose side of stock. Tighten down the 7 mm screw, replace the black cover with a thin bead of silicone sealer and you're done.
I tried one, three, and five teeth... one didn't seem to do much, five actually reduced power. Three was just right. Stay with three teeth because the down side of too rich a mixture will be increased emissions, and possible damage to the O2 sensor and/or catalytic converter. YMMV.
I can report that this tweak helps solves some perceived Digifant driveability problems (assuming all else is in order). Hesitation is reduced, throttle response is crisper, and there is mildly quicker acceleration in the lower gears due to increased torque. Gas mileage does not appear to suffer much.

Has anyone tried this?
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Re: Fiddling With the Air Flow Sensor...does this work? (DriveVW4Life)

well, apparently the one guy who wrote that thread, but would advise against it...like he said, screw up and it might NEVER run right...my throttle response was greatly improved on my digi motor with just a k and n. it would not seem to be worth messing with a sensitive and vital component. my two cents
Re: Fiddling With the Air Flow Sensor...does this work? (Tornado2dr)

I already did it and I didn't have to loosen any bolts. It's simple to do really...just be careful.
The only reason I posted the whole article is for other people to see and so I could see what other peoples' input was on it (If they had done it).
I haven't driven my car since I did the modifiction, so I thought I'd post a question about it on 'tex.
Re: Fiddling With the Air Flow Sensor...does this work? (DriveVW4Life)

fair enough...i just don't like messing with stuff like that. let us know tomorrow how the car feels!
Re: Fiddling With the Air Flow Sensor...does this work? (Tornado2dr)

Well, I've driven the car several times since my modification of the AFS.
I can't really tell that there is a big difference. It does "seem" to feel like there is better throttle response and less hesitation. Then again, I can't be for certain that it helped at all. But when you think about it...
...Why do we all swiss cheese our airboxes?

[Modified by DriveVW4Life, 1:06 PM 12-4-2001]
Re: Fiddling With the Air Flow Sensor...does this work? (DriveVW4Life)

do this and you will ge tbetter throttle responce: take the little plug off the back of the mafs (its black rubber and faces up, you do not have to take the sensor off to get to it) once its off you take the allen key (i dunno what size) and turn it clockwise about 1/4 to 1/2 turn, you will notice instantly better responce, i guess its the idle air mixture, but it helps all through the rev range, when i got my ABA timed the mechanic who did it (used to work at vw dealership) told me he adjusted it because the responce was a little wose then he liked, and it helped, and if i noticed anything weird about how its driving i could adjust it myself pretty easily without screwing anyhting up, richening it up a little really helps. if yu dont like it, set it back ot stock.
Re: Fiddling With the Air Flow Sensor...does this work? (Andrew Foss)

i did that on my 92 over a year ago and its ran great..... does cream up throttle response a bit and is worth the 10 minutes it takes to do it... JMO
Re: Fiddling With the Air Flow Sensor...does this work? (DriveVW4Life)

I have done the AFM Spring Tension mod and I didn't notice any difference at all. I set it back to stock. I will try the plug and allen key trick though. I am desperate for throttle response. What else can be done other than a air intake, AFM mods, and AMS chip?
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