Volkswagen: Fast idle with 78 vw type 2, fuel pressure regulator, vacuum leaks

Question
Hi Ron,
I have a 1978 type 2 volkswagen bus, manual, with fuel injection. My idle speed is high--about 1200 rpms. I have the bypass screw turned in all the way and that's as low as it gets.  It should be about 850 rpms.  Anyway, I've checked for vacuum leaks and didn't find anything.  I used a vacuum gauge and got a good reading.  I've checked everything in the fuel injection system: the auxiliary air regulator, decel valve, fuel pressure regulator, injectors, cold start valve, temperature sensor 2.  I replaced temp. sensor 2 and fuel pressure regulator.  Also replaced most vacuum hoses and injecor seals and air intake runner gaskets. Did electrical tests on all parts of fuel injection, everything was good.  Found out that the ecu was not the right one--it was for a 75 bus, so I replaced it with a used one for a 78, but it didn't make much of a difference, if any.

I was wondering if weak springs in the distributor could cause a fast idle.  I did mess around with the distributor a while ago and took it apart out of curiousity. Didn't know at the time that the stuff inside is sensitive. What do you think?

I'd appreciated any help. Sorry for the long message.
Thanks,
Eddie

Answer
Eddie,

Well put description.  This leads me to believe that the distributor is having a problem or the timing is too far advanced, which can cause a dangerous overheating situation.

Check your service manual for the correct timing, loosen the distributor and check it with a timing gun or statically time it.

Let me know how you make out.

Ron