740 estate. B230 - intermittent starting problem

edalbesor · Post by **edalbesor** » 30 Jun 2008, 04:01

Hi Guys,
Me again!
Have I got the world's most unreliable Volvo?
After the long and painful nonsense earlier this year I now have another starting problem I hope one of you kind fellas can help me with.
Simply, when I turn the key there's nothing. I hear a click from under the bonnet somewhere but there's no crank. It never happens from cold, only once it's warmed up. Many times I have been sat in a car park for 20 mins until, suddenly, she turns over and starts. It's possible that, as it's now quite hot here, that heat might be a contributory factor but I'm not sure. The last couple of times it happened I noticed the sun had been beating down on the bonnet for how ever long I was in the store.
Any ideas out there? It's driving me mad here because although it only happens maybe once every 2 weeks, when it does it's always at the wrong time!
ATB,

edalbesor · Post by **edalbesor** » 07 Jul 2008, 05:27

Forget the sun on the bonnet theory, it failed to crank the other day when I parked in the shade!
There has been a suggestion that it could be the alternator "overheating". Would this cause it to not crank?

wojeepster · Post by **wojeepster** » 07 Jul 2008, 06:46

No it is not the alternator. A couple of things to check. The electronic part of the ignition switch can go bad and cause this problem. Measure to see if you are getting 12v at the small terminal on the starter when you put key in start position. If not bad switch. They are known to go bad. Unplug and two screws and it comes off. You could also have a bad solenoid on the starter. If you have 12v in start but it does not engage starter bad solenoid..... Hope this helps.

edalbesor · Post by **edalbesor** » 07 Jul 2008, 08:33

Thanks Jeepster,
I replaced the back end of the switch back in January when she would crank but not fire. Admittedly it wasn't a new one but I'll try both your suggestions.
The hard part is that it's an intermittent fault - the worst!

wojeepster · Post by **wojeepster** » 08 Jul 2008, 12:19

Might be fuel pump, just a possibility. Does it cut out while you are driving along, then take 20 min to restart? I would suspect fuel pump relay if so. If you have a timing light point at your face, crank and see if you are getting spark when problem occurs. If so then it is probably related to gas or fuel pump relay (controls both fuel pumps AND injectors)

edalbesor · Post by **edalbesor** » 09 Jul 2008, 00:32

Would a fuel pump problem stop it cranking? I thought that was the problem back in January when it would crank but not start. I swapped a huge amount of bits and eventually when I replaced the back end of the ignition switch it lept into life.
It's so frustrating as it didn't do it at all last week and then, on Sunday as I was leaving to go watch the Grand Prix, - nada! I missed the first 15 laps or so in the 20 mins it took for the problem to resolve itself.

wojeepster · Post by **wojeepster** » 11 Jul 2008, 05:08

you are correct a bad fuel pump/relay would NOT keep it from cranking...