General: 850: random no starts

[marcos v8]

hi all
after suffering many random no start probs with my 850/2.5/10vale1996 i had a look at the fault codes thing under the bonnet code was 231 [ventilation damper motor position sensor open circuit or shorted to 12 volts]
could any body explain this to me in plain english ie where it is and does please; and could it really cause very random no start probs .after reading a lot on here i have changed the fuel pump relay as a start but only time will tell if that is the problem
many thanks.

[biglass1980]

Dont know whether these websites can help you.


http://www.matthewsvolvosite.com/volvo-repair-database/volvo-850-trouble-codes/[/URL]

http://www.volvoclub.org.uk/tech/ser...ystem-Auto.pdf

[marcos v8]

thanks for the link that takes some reading lol.funny thing is it apears to be refering to aircon ;wich isnt fitted to the car i think im going to have read it a few more times

[marcos v8]

well after re reading the manuel it seems that i checked out the dashboard
instead of the fuel and ignition ecu [pratt] any way did it properly today and got 1-1-1 =no faults stored wich is good.as i stated before i changed the fuel pump relay for a new one and time will tell if this was the cause of my problems does any one have any suggestions as to other likely causes of totally random none starts ? many thanks chris,

[RollingThunder]

Can you describe the no-start situation a bit more fully? When you turn the key are the dash lights still illuminated? Can you crank the engine or is it all completely dead?

My initial guess would be a worn ignition switch, but that'd need more diagnosis before coming to a def conclusion... The 20v engines are known to have a problem with tappets sticking but this affects the 2.0 more than the 2.5...

Yep, def need more info

I know these random faults are frustrating, but keep the faith !

[marcos v8]

hi rt
the symtoms are these the car cranks over just fine in fact it has allways started from cold but if say i did a couple of mile then go into a shop for 5mins
it prob wont start when i come out but i cant replicate it .,this has happened a few times after various mileages usually under 5 iwas thinking it may be temperature related,how ever after a 4 day lay up coverd in snow and ice
it started up like a good en and sat there ticking over while i cleaned off for perhaps 15 mins, the temp gauge was at normal but as i tried to drive off it
just died,tried the foot to the floor method to restart plenty of cranking as usual but no fire up again,the funny thing is if i leave for 10-15 mins its fine runs great, only once has it hiccupped a couple of times then died at the junction but i did manage to restart and after abit of chugging it cleared and
away we went that was on monday so i changed the pump relay on tuesday.
must add that short trips are the exception not the norm
thanks chris.

[RollingThunder]

OK, no dying while driving along and no electrical failure - that would tentatively rule out the ignition switch.

It sounds very similar to a problem I had with an old 940 of mine. It would start fine, but could die without warning - usually when pulling away, either off the drive or away from the lights etc. It turned out to be the MAF in my case - but it did set a fault code...

A leaky vacuum pipe could also cause contribute to it.

The other likely candidate is the fuel pump relay, but as you've already changed this... I reckon we need to see whether you're getting fuel and a spark when this happens - which is going to be a bit awkward That will rule out fuel and electrical issues leaving the sticky valves as a possibility (a compression test will help diagnose this - but again only when the engine stalls...)

If anyone else can throw in a few thoughts here, feel free - I'm scratching my head really

[marcos v8]

hi rt
yes its an awkward one ,my plan at the mo is to see how it goes with just
the new relay before any further work ,as i do know for sure that the previous owner had fitted a second hand one after experiencing hot start issues, would i be correct to think that cam sensors etc would either work, or not?but at the very least would throw a code?the more i think about it the more conviced i become that is connected to shortish journeys ,it could be a gremlin rather than a fault lol
many thanks chris.

[RollingThunder]

Couldn't find the one about the tappets sticking, but I did find one suggesting alternative (2.5 20v) sparkplugs and an italian tune up This might be worth trying - certainly and easier/cheaper option than a cylinderhead overhaul...

[EMM]

I There i am having exactly the same issue. It won't start unless i do the hold go pedal down for three minutes while cranking.

It will run really rough between 1,000-2,000rpm and if i don't catch it, it will stall. However once the engine is warm the problem goes away.

Then i'll leave the engine cool down and the whole process starts again.

I haven't replaced anything yet but i have spark, 12.6volts at battery, 13-15 during running, engine cranks no issues. Correct oil and level. No waring lights on the dash board when operating. It's just odd.

Any ideas?