1986 volvo 240 DL

Our 1986 Volvo 240 DL will start, run 5 seconds and then stall. There is no spark. After 3 minutes spark has returned and engine will start, run 5 seconds and then stall again. No spark. This can be repeated all day! Any ideas will be greatly appreciated!

This is a fuel injected car, right?

It sounds like the ECU is not getting a tack reference signal from the distributor/ignition module.

Yes, fuel injection. Why would spark return after a few minutes and then run for only 5 seconds?

Bad ignition module can cause this. Check the primary and secondary coil resistance as well, just to rule out the coil.