I have a Volvo 850 that is intermittently failing to start. When the starter is activated, the car sputters at a low idle (500 RPM) then conks out. Pumping the accelerator has no effect.
So far the problem has only occurred after a short trip. For example, I will go to the store and when I come out, the car sputters and will not start. It has never happened when the car has been sitting for a long time.
In all cases so far the car has always started after some delay. For example, the first time it happened, I tried for about 5 minutes to start it with no luck, then I went and talked to someone for 45 minutes and the car started. The most recent time it happened, I went to the grocery store, then went to another store a short distance away and then the car would not start. I tried for 10 minutes with no luck. Then I had lunch, read a chapter of a book, and then the car started about 30 minutes later.
I suspect that the problem is either that the fuel controller is failing or the fuel pump is failing, but I do not know how to discriminate between the two.
How can I further diagnose the problem?