Question-------------------------
Followup To
Question -
Occasionally, but usually after not using my Volvo for a few days, it will crank, but not ignite. Later, maybe that day or the next, it will start. The first time it did this and it didn't start the next day, I had it towed and of course, when it was unloaded, it started right up. I left it with the shop for two weeks and not only could they find nothing to repair, but it started everyday. Since I live ninety minutes from any reliable Volvo mechanic, I asked them to replace the various things that could be causing this, but they objected to this idea. It was fine for a year and did it again about two months ago, but this time I was more patient and it started after two days. Three weeks ago, same as above. Yesterday it wouldn't start and not today either. As you will note, its becoming more frequent and I know that eventually it finally won't start, but this pattern could go on for a long time so I'm still considering replacing the appropriate sensors and relays based on the age of the car and milage, almost 100,000 miles. I have also noticed the engine hesistating for a split second as I come to a stop and then picking right up. It has only done this a few times. What suggestions can you offer and do you think I should replace the sensors and relays myself?
Thanks.
Answer -
Sometimes its necessary to wait until the problem reoccurs before it can be diagnosed. But this is ongoing for you for a year so definitely I recommend some repairs.
1. Fuel pump relay
2. crank sensor; on top of the transmission tunnel by the firewall.
Both of these are not expensive and easy to do. There are other more expensive items that can also cause this problem but do the top two first. Its hard to recommend anything else because it would just be guessing.
When it doesn't start next time, stick your head out the door and listen for a buzz from the fuel pump when you bump the engine (short crank on the key ). This can help with the diagnosis.
Additional question:
If I do or don't hear a buzz from the fuel pump, what does it indicate?
Thanks
AnswerThe car's fuel/ignition system needs to see a ignition pulse before fuel pump energizes. If fuel pump does make noise, it means the ignitom system is ok on the primary side and this means the relay is probably ok. If the fuel pump doesn't buzz, you'll need to check the above items and also check the fuel pump itself by running fuel pressure checks on the system. ( This part needs to go to the shop because of special tools )
