SC leaning out

Mike the mechanic · 04-29-2002, 06:22 PM

Hey guys, I have a problem with a 1980 SC. It runs nice at idle but leans out as the rpm goes up, and really leans out during load. I have an air/fuel guage hooked up and I notice that with the fuel mixture set ok at idle, it starts to lean out at 3000 rpm and starts to stumble and pop the higher it revs, this while revving it in neutral. Engine tempurature has no influence. Driving is very hard and when I adjust the fuel mixture excessivly rich at idle (black smoke) it revvs up beautifully. It seems as if there is too much control pressure but it is a new warm up regulator and all wiring is ok. Any Ideas?????
Thanks in advance!!

Mike
86 Carrera t

1980SC · 04-29-2002, 07:34 PM

Check your fuel pressures !

I also have a 1980SC. European version. I took it to a dyno one day and found out it was running way too lean under load. When I checked my fuel pressures, I found that my control pressure was exactly equal to my system pressure. My problem was the little disc in my WUR was stuck. After cleaning it my control pressure dropped down, but not as low as it should have. Come to find out, the previous owner replaced the WUR with one for a U.S. 1980SC. I had to replace the WUR with the correct one to finally get the control pressure low enough that it wouldn't run lean under acceleration. I know you said you have a new WUR, but they can get 'stuck'. Also make sure it's the correct version.

Of course it could be something completely different...

-Rob
1980SC euro

Mike the mechanic · 04-29-2002, 08:29 PM

Rob, thank you very much for your help. I will check out the part number to make sure it is the right piece. If it is, I'll check the pressures also.
Thanks again!

Mike
86 Carrera t

targa4me · 04-29-2002, 10:21 PM

Check all lines for vacuum leaks and watch out for melted pistons.