With the ignition switch in run position (pos 2) I have 12v to coil. But, in start (pos 3) there is no 12v to coil! As a result, I have to separately switch the starter solenoid to start and run the car. Bad switch???? It's driving me nuts. I bought the car as a complete basket case, so didn't have the luxury of knowing any idiosyncracies beforehand. Any help appreciated.
What year/version 308GT4? Pretty sure that your symptom would condemn the ignition switch itself (if no modifications), but, IIRC, the early GT4 have a more complicated setup to switch out the ballast resistors during starting so that might up the chance that someone has done something strange, or maybe something in that more complicated system could fail that would cause your symptom. If you give year/version, I'd be glad to have a quick look at the schematic.
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/124069606733 After about 50-60k miles the contact to solenoid goes bad. This attaches to back of ignition switch. Original Bosch, great price. I also wire a flyback diode on lead to solenoid to prevent wearing out of the contact.
If it is a switch be careful of what you buy to replace it. There are Chinese knockoffs being sold that are junk. I got stuck with one for my own car and it would just shutoff driving down the freeway. The good ones are from one of the German suppliers and are marked accordingly on the back. I did get Ted Rutland back though. His GTC4 broke down in my shop with a bad switch and I installed the Chinese one he sold me.
Thanks guys! It's a '75 US version. I hope it is just the switch, as it can be solved easily (kinda) with a few bucks. More like a Biturbo owned you! Me and Vince too! Arrrrrrrrrrrrrgh!
Ebay item above is original German made Bosch item. I bought extras for my Duetto which uses the same switch contact block. The price is very good vs others.
The schematic in your 100/74 OM shows you have the more simple ignition system design that always uses the ballast resistors = pretty strong sign that it is an ignition switch problem if you have +12V at the coils in Pos II, but don't in Pos III.
Hey be nice. In addition to my 75 GT4 I also own a 87 Biturbo SI. Look at it like this, if you can figure out the on going electrical problems with a Biturbo all these other problems with a GT4 are of a minor concern. There is nothing like the wiring print for a Biturbo, if you can troubleshoot these you can fix almost anything. And yeah I love the damn thing--when nothing is inop or broken.