hello,

I just installed an air/fuel ratio gauge this past weekend in my 81 turbo, and I noticed that it is right on the lean edge, and under certain boost conditions it will step slightly into the lean. So I checked the fuel pressure and that was good. Its a new alternator, so that can't be it, and all of my connections on my computer are good. So the next step I thought was to slightly adjust the AFM to make it run a little more rich, but when I took the cover off it(metal bracket slightly covering and holding it down), I saw no adjustment screw. I look under it, on the sides of it, in front of it, everywhere with no sucess. Even my buddy looked for it with no sucess. So if you could send me some help out this way, because this is making me curious as to where mine is. If there even is one. Also if there are any other solutions to my lean condition please let me know. Your help is greatly appreciated....

Jason Coleman

 

Before you adjust anything, I have a few questions for you. Did you let the motor warm up and drive around town for about 15 minutes? Also how new is your O2 sensor? The a/f gauge will read lean until the O2 fully warms up and if your sensor is old it will give a bad signal. I have to drive around the block for a while before the a/f starts to do its "dance" back and forth across the gauge during cruising. Anyways, to adjust the a/f ratio, pop the black cover off and you will see a plastic "gear" held by some tiny bolts. Mark the setting you have with some white out or similar item so you have a baseline established. Loosen the bolts, but keep your finger on the gear to keep it from moving as the tension will be released once you loosen the bolts. Tighten the gear to make it leaner and loosen it to run richer. Generally if you're not running bigger injectors, you don't have to worry about adjusting the gear though.

John 82ZXT

 

thanks for the help...but before I adjust my afm (knowing my o2 sensor is good) could this also be a problem from the fuel pressure regulator???? Or maybe even the fuel pump going out???

 

Check the fuel pressure with a fuel pressure gauge. You can go the easy/cheap route (not safe for daily driving tho) by buying a 50 dollar gauge from Summit and duct taping it to your windshield to see if fuel pressure falls off during driving. If you're on stock injectors, I'd look for vacuum leaks, fuel issues, cylinder head temp sensor, etc. before messing with the air flow meter. Vacuum leaks are the killers since there are miles of lines in our engine bay! My fuel pump crapped out on me a couple weeks ago and it damaged my motor (gauge was reading lean the whole way back from LA) so I'm going to find a replacement, probably gonna have to use an n/a motor since I can't find a turbo engine around here. If you're turning up the boost, be sure to buy a Walbro fuel pump and larger injectors (any Mustang turbo, Ford Turbocoupe, or Merkur XR4Ti injectors will work). When buying the injectors, make sure they are the brown top ones (370cc) and not the green top ones. (green ones are only 300cc or so)

John 82ZXT