My 1992 940 Won't start sometimes

[spyglass]

Hello, This is my 1st post on this board and I own a 1992 940 Gl and my problem is Car won't seem to start after its been driven for about 45 min.And if it is left unstarted for about an hour.
It won't happen after it is turned off and started after 15 min.And It will always start if I get a jump.
Mechanic friend checked alternator and its fine but didn't check anything else,The car will always start after its been sitting for a few hours,always starts in morning.It seems to be worse in the warmer weather,What could this be???

[Volvo1man]

Hi spyglass. This may or may not help but I have a 1994 940 Turbo Wagon and it had problems starting and running that lasted several months. The symptoms were intermittent. Long story short in my case it was the rpm sensor located on the back of the engine. It seems there was a common problem with the insulation on the wiring - it would become cracked and brittle and come off, causing intermittent shorting of the wires. After replacing the rpm sensor I haven't had the problem again. It might be worth a shot in your case. Find the wire going down the back of your firewall right behind the engine and follow the wire all the way down. If you feel bare wires or cracked or missing insulation, that may be your problem. Just an idea.