Another intermittent 240 start question.

Papajazz1973 · Post by **Papajazz1973** » 01 Jul 2024, 14:36

My 1991 240 very randomly decides not to start. We took it to a Volvo shop and they were able to get it to happen one time in a week, and confirmed it was not a fuel issue. They were not able to get it to happen again. It happened again today. When it happens, it’s usually when we took it out somewhere, left it for hours and then tried to start it again. It turns over and over(not battery or starter) but won’t fire up. The solution is to let it sit for 15-20 minutes and eventually it just fires right up. Have replaced, the CPS and the Fuel Relay sensor. Can anyone think of something that would reset after 15-20 min and lets the car start?

Post by **volvolugnut** » 01 Jul 2024, 17:28

When it does not start, immediately put a timing light on the coil to distribitor wire and se if there is spark. Also, if you can install a fuel pressure gauge that you can leave under the hood, check this gauge for fuel pressure when it won't start.
Check all wires in the start circuit for bad connections and fraying.
Find your fuel pump relay and work the connections on and off when it will not start. The relay may also need to be opened and connections resoldered.
Does it ever die while running? Does it have good maintenance or does it need some TLC?
volvolugnut

Papajazz1973 · Post by **Papajazz1973** » 01 Jul 2024, 18:30

Thanks for the note. It does not die once it starts. The car has 89k miles on it and was incredibly well maintained. I’ll do some research into the spark. As I said, the shop I took it to said it had fuel pressure when it wouldn’t start, but was not able to check for spark. That will be my first thing. I’m a do it yourselfer mechanic, so I’ll look into the timing light on the coil. I just wondered if anyone had any idea what giving it 15-20 minutes after a no start would change it so that it can start. I don’t know if it has to do with temperature or something else. The no start is so inconsistent, but the wait time and then start is pretty consistent… thanks!

Post by **volvolugnut** » 01 Jul 2024, 18:45

If it is getting spark plugs wet from excess fuel, it might take 20 minutes to dry. When it happens again, pull plugs and check condition. Injectors might be leaky.
If plugs are dry after no start, spray some starter fluid or carb cleaner in a vacuum line and try again. Fuel to cylinders might be stopped by injectors not firing.
Keep in mind you must have spark and fuel at the proper time and near perfect ratio.
I would put some money on an electrical problem.
Intermittent problems are tough. Don't give up. A low mile 240 is worth the trouble.
A shop that was unable to check for spark is no shop for this car.
volvolugnut

Papajazz1973 · Post by **Papajazz1973** » 11 Jul 2024, 09:46

I had replaced the fuel pump relay, now when I switch it on, I’m not hearing the relay click and it won’t start up. Is it common for a replacement fuel pump relay to also fail? What cause a relay not to work? Is it the sign of a different issue, or do I just have a bad replacement relay?

Post by **volvolugnut** » 11 Jul 2024, 12:31

Years ago 240 Volvos had lots of fuel pump relay problems. I have heard of road side assistance drivers carrying one to get Volvos running again.
The problem was often caused by failure of the solder connections. If you carefully remove the plastic relay cover, you can heat the connections with a soldering iron and 'reflow' the original solder. This often fixes the relays.
volvolugnut