Volkswagen: 78 superbeetle run very rich, fuel pressure regulator, voltage spikes

Question
Hi Ron, my wife's 78 superbeetle is running rich need some help, here is want i've done so far.
spent all day sunday trouble shooting with the inform. you sent me. here what i got
1.. coil , spark, timing > ok
2.. no trottle valve
3.. no altitude comp
4.. Auxiliary air valve > ok
5.. cold star vale > ok
6.. thermo-time sw > ok
7.. fuel pressure > ok
8.. Pre-resistors >ok
9.. injectors to gound > 0k
10.. temp sensor II . ok

I cleaned and check all grounds> ok
all sensor and wiring check out as being ok , i ever remove the wiring harness and check each wire for continuity. Air flow valve pin point test (ok) I even discontected the Alt. to make sure i had no voltage spikes. the only thing i notice is with the AFV off the engine it seemed to idle mush better. could the afs be bad even know the pin point tesrt was ok.

Any help would be great.

Thanks steve

Answer
Hi Stephen,

1) I know you checked the temp sensor II, but double check the resistance on that.  That normally causes it to run rich.

2) The engine should run smooth but not accelerate with the AFM unplugged.

3) You may want to check the spring tension on the AFM flap.  Sometimes these loosen up and dump more fuel than necessary into the engine.

Finally, check the fuel pressure regulator.  It may either be disconnected or have a weak vacuum signal.

Good Luck,

Ron