Running Lean???
 

'81 SC. I was driving down the freeway, and all of a sudden, the throttle felt 'funny'. kinda of a slight loss of power. upon exiting and coming to stop, the idle was rough, and low, about 750rpm. acceleration from 1-2000 rpm was very sluggish, but at higher rpm better. replaced plugs, rotor, distributor cap, and no difference noted. decided to play with the mixture, and by making the richer (clockwise turn about 1/4 turn), idle and accerlation better, but not quite right. looked for any obvious leaks, and could not find any. only thing noted, was that the hose from WUR to thermo valve was not connected, but that looked to be not connected from long ago. Any suggestions on where to check next would be appreciated. Thanks

By what you describe maybe the fuse for frequency valve. Yellow 5amp. It's shared with your interior domelamp- does it light up?

I find the throttle response crisper when it's leaned out, I try to take to the lean side, it sounds crisper as well. My brother and (has 1 86 930) leaned his out too and were very happy with the results.

The hose you are talking about pulls vac at part throttle to lean out the mixture and richens under heavy load. I tried attaching mine to diff vac locations and the one I find that works best is the one at the back of the car (closest to you), the bottom of the 2, aiming towards the left of car right above the thottle plate.

I rigged up an adjustable valve inline so I can go leaner on the mixture and still be rich enough at low throttle by limiting the vac to the WUR.

I also recurved the distributor to match the changed gears and SSI and sport muffler, this and the proper mixture made a huge diff for me.

my dome/interior lights are working. I checked the relay under the passenger seat and upon pulling it in and out while the car was running, i can hear/feel the relay clicking, but whether the relay was in or not, the rpms did not change. I do have the mixture set rich since that is what I had to do to compensate for the bad idle. Should I check the relay in and out with the mixture more lean, but rough idle to see if it stalls out with the relay pulled. I then checked the frequency valve, and could not really 'feel' any vibration, therefore my assumption is i have a bad frequency valve. can someone direct me, or instruct me on how this can be removed/replaced, it seems to be in a hard to work in area.

If that relay is faulty you will not notice a change in rpm when you pull it out. Inexpensive to replace, then go from there.
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1981 SC

Interested in the outcome

I have the same problem...

Full tune up and car loss power
Can't drive the car anymore..

The car act like very few fuel
Fuel Filter has been changed

Tx to Pelican!

Daniell911

I went through many steps, like checking the relay under the passenger seat. Then checked if there was voltage going to and resistance measured at the frequency valve. The frequency valve seemed to be good, but no voltage getting to it. The problem turned out to be a broken solder joint on the circuit board under the passenger seat (one of the power lines). So power was getting to to the relay and to the computer board, but not working past that. Once that was restored, everything runs great (after leaning out the mixture again). The other area to check would the O2 sensor. Good luck

if someone needs a good Lambda brain under the passenger seat I have a tested good one for sale here-

http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/365118-lambda-brain-1983-sc.html