Yesterday, driving the ’86 syncro, going down a long hill and the van died (noticed when throttle re-applied). Pulled over and it started back up after a couple of tries, funny I thought. Got to my destination and parked for a few hours. Then I tried to start the van and it turns over and catches for a second then dies. Try again, same, then subsequent tries has it turn over but no start. Noticed no fuel pump noise with ign on (and my van does cycle fuel pump with ign on.)
Looked in the engine compartment with ign on. No hum from idle valve. Pulled the fuel pump and ecu relays and replaced with new (during which I jumped contacts and did get fuel pump to run). No change, no idle valve hum and no fuel pump, and no start.
Then I pulled cover from fuse panel and pushed on fuses and generally jiggled panel. Fuel pump cycled on, and I could start the van. Drove home with no problems. I suspected the known problem of the D15 connection on the back of the fuse panel. This connector supplies power from ign switch back to engine compartment and can power (depending on van year and VIN) the fuel pump relay, the idle control unit, coil, and the crankcase breather heater. Gets a little muddled in that the crankcase heater was retrofitted to early ’86 vans (and that seems to be the situation in my case). The wiring diagram shown below is specific to my van.
No matter what version you have, the D15 connector is oveloaded. Note in the diagram there is another connector in the “D” plug that is on same current path as D15. This unused connector, D23, is a bigger Molex than D15. Today I pulled the fuse panel down and removed the “D” plug. D15 looks like it has overheated.
I couldn’t find a spare larger Molex connector to make the switch over to D23, but I did put a new connector on the black wire to D15 and spliced in a pigtail so that when I get the right connector I can plug in to D23 (see the unused larger hole at the bottom?).
Update: I did finally find a large female, molex type, connector for that pigtail, and it is installed into D23.
I can’t say for sure that this connection was responsible for my no start problem yesterday, seems likely though.
Addendum: dug up the Samba thread on this subject, worthwhile reading.