This has my tech and I completely stumped.
1991 740 sedan, 225170 miles.
My car has had two episodes of cranking but not turning over. My tech had tightened some loose ignition wiring after the first incident...computer diagnostic had shown the R131 code for "no rpm". Once the wiring was tightened the car fired right up. The starter, alternator, battery, fuel pump,fuel pump relay, and all other systems checked out fine.

The same thing happened a couple of weeks ago...same code, all other systems OK. My tech pulled the #1 fuse out, waited a couple of minutes, re-inserted the fuse, and the car started right up. He did this on a hunch as he was at a complete loss; the fuel injection system had checked out fine. We are both stumped and want to know if anyone else had encountered the same problem. He seems to feel it might be a computer/memory issue.

I live in a mild climate; both episodes occured when it was about 65-69 degrees.

The car is in excellent shape with the exception of this one quirk..we are both puzzled.


thanks,
E
1991 Volvo 740(Nigel) 225,170 miles

Dear E:

Try changing the RPM sensor on the flywheel housing. It plugs into the harness on the firewall. It costs about &40.00 at www.fcpgroton.com. These sensors are known to fail and I have had 3 of them go on me alone in 3 different cars.


Len

Len-

Thank you. I will order one from the site. In talking with a neighbor who has two older Volvos, he has encountered the same thing and also suggested replacing the RPM sensor. Sounds like a consensus!

Thank you again,
E