Let me start by saying I know next to nothing and just got lucky. Read on.

My wife's 90 760TI (202K, Volvo rebuilt engine, trans, turbo, alternator about 150K) began randomly failing to start cold about 4 months ago. First time it cost a tow, labor and OEM Interference relay. Worked fine for 2 days. Then I installed a new Crank position sensor. Worked fine for 2 weeks - progress, I thought. But the problem presists. If it starts, it runs/restarts perfectly - no surges, no fluctuating tach, etc. (Here comes the "I got lucky" part.) After verifying once again fuel pump was working (already checked the relay) and there was no spark, I started tugging on wires. The one that "fixed" the problem was either the wiring/connector to the diagnostic block OR removing and replacing the single wire that plugs into the top (not even minimally corroded, #6 pin if I remember correctly) - works every time.

First, FAQ doesn't seem to address this quirk, so: is this (not the cold start failure, but this cause) common; what is the purpose of the wire into the connector block and should it even be connected; could this be a problem in the loom that feeds the block? Any other info would be helpful. Thanks again.

Jim Weiss
83 245T, 90 744T/M46, 90 760T, 93 940T wagon, still want more . . .