http://www.youtube.com/watch?v=7y-KQDm3cDA

Finally broke down and spent a few buck on an a/f gauge to try to get my idle mix dialed in correctly on my 87 22R. It's the Cali emissions, so it has an O2 sensor.

Things seem about right to people? I have to adjust the screw far to either limit to get any kind of steady rich/lean reading. I know it's not wideband, so it's not going to be terribly accurate, but still...

Any insights are appreciated.

correct me if i'm wrong ...

but isnt that a "driving" interpetation of the readings ?

meaning .. when you "step" hard on the skinny pedal , the guage will go in the "MAX" reading .. but if you feather the skinny pedal it will fluxuate as per fuel/air intake ?

kind of a visual fuel savings ?


.

Well, I know it's not massively accurate, and you're probably right about it not being much more than a visual aid, but it has helped me diagnose at least one problem.

Randomly, at idle, with no apparent pattern, the revs will drop to about 400 for a couple seconds and then slowly come back up. Might happen twice in a month or twice in a week. Really sucks at night with the headlights on because it nearly kills the engine.

At least now I know it's going rich when it does that... great, another problem to track down.

I suppose this means this thing is going to be nearly useless for idle mix tuning... <img src="/forums/images/graemlins/angry.gif" alt="" />

pretty much .. but it's cool .. and will absolutly help you save fuel .
my grampas 65 Dodge had one .. well actually he added it as an accessory back then , when he was hawling 5th Wheel trailers down in to the US .

is this a stock carb?

I have the autometer led gauge that has bars instead of the semicircle one. I've used mine to help me get my Weber 32/36 properly jetted. there's not really much to the stock carb, iirc though, is there? idle and mix screw? I forget what the adjustment procedure is for the mix screw. have you read anything about that anywhere?

along the lines of what CJM says, watch your meter while you're driving. basically, it should go somewhat rich when you get on the gas, and go lean at cruise or under low to no load conditions. don't worry so much what it's doing at idle.

secondly, I've been hard pressed to find information talking about just what exactly the engine needs for the different run condtions - idle, acceleration, cruise, etc. kinda hard to use an A/F meter to your advantage without that info.

looks cool though
now get it in the cab

Accel you want rich.
Cruise and idle you want stoich (lean)

I did wind up mounting it inside, actually where the 12V socket would go on the higher models.

It only reads rich or lean at idle at the two extremes of adjustment, but by watching how far and how quickly it sweeps back and forth, and by watching the vacuum gauge, I think I have the idle mix dialed in pretty well. Also, there is a very small amount of adjustment on the fuel metering rod, so you can adjust how much fuel comes in when the secondaries open up. I've been able to lean that out a tad with good results.

Now I just have to figure out why the secondaries keep dumping fuel after I shut it off.

It appears you have a narrow band gauge(slow dial up and video don't work well), and not the wide-band(cost about $350) which is what you want to use to dial in the A/F mixture, if so, it is supposed to cycle from lean to rich when at idle, cruising rpm, etc. When deep into the throttle it should run rich, and usually when dropping completely off the idle it will sit on the lean side for a second or two and then back to the fluctuating.

I find mind most useful when pulling a grade or taking off from a stop, it has improved my non-hwy mpg an average of 1-2 mpg's. Not much, but it will pay for itself in the long run.

There is a pretty good price ($205) on a wide band sensor and gauge kit below:
- http://forums.vwvortex.com/zerothread?id=4428697

Luis at paradise racing has widebands for $300 that also datalog for 2 hrs http://customtacos.com/forum/showthread.php?t=125870
It will do AFR vs RPM vs TPS vs boost/vacuum (if applicable) or any other gauges you have.

I got one for my truck.