850 NOT STARTING

[DLM48]

This is historical

reversing out of the drive one morning my 850 2.5 20V Est stalled - hey i stalled it

after that it would not start

the short version is

i replaced - cam sensor - coil - dist cap - leads - new plugs - crank sensor - tried the oil down the bores trick NOT a GOOD IDEA - changed the ECU's - THEN dicovered it would start with a push

so replaced the starter - and the battery

had a great vehicle electrician take it apart - and i mean he took it apart - checked every wire for continuity every circuit and sensor spent days and days on it - he was determined to fix this car that had him pulling his hair out.

hung a occiliscope on it and discovered when it was cranking it was generating LOTS of electrical noise

fitted new earth straps between body - engine body - gearbox and engine - gearbox

THEN slipped the engine and gearbox apart and cleaned the two faces between engine and gearbox - this fix came from someone in America

woooooo hoooooooo it starts

now it is fixed well 99% fixed

though sometimes it still likes to play dead BUT if you floor the throttle it will start in about 30 secs - feels like hours though.

SO IF yours wont start BEFORE you get too deep find out if it will start with a push and then you will understand that ALL the components on the car are working fine and you have a car that is creating electrical noise on cranking that is upsetting the ECU and the various sensors/pickups

i hope this helps someone

if it does mail me (email addy removed) please

VOLVO dont seem to recognise this problem

thanks and regards

safe driving

David

[v6en]

Hi mate,

By gum you didn't half pull out all the stops there!!
My 850 made a scratchy noise a couple of times on starting about 2 months ago, and then one day when i went out in the morning it refused to start. sounded strange, something in the note of it made me sure that it wasn't going to catch no matter how long i tried. got it lifted and taken to my friend's garage, who changed the starter motor, the leads, and cleaned the plugs which were well blackened by this point, and got it going. he remains convinced that it doesn't fire on all cylinders when it first starts though, although he's not 100% certain what the problem is. it was fine anyway up until yesterday whereupon it wouldn't start again. so we'll see what comes of it this time once he's had another look. i'll tell him what you said though. haven't tried pushing it, as it is facing up the way at the top of a hill, ouch.

jacq.

[DLM48]

yes sounds like a turbine winding up when it fails to start almost like there is no compression

mine still does this now and again

Then the only way to get it to start crank it over at full throttle or with a push - it always start easy peasy with a push or a tow

turn it around at the top of your hill let it roll down the hill backwards then spin it around on full lock and off you go forwards OR if you are feeling brave start it in reverse :-)

do keep updating us on how you get on with this problem

[ShadeTek]

This noise on start up reminds me of a computer problem a few years ago. This has nothing to do with cars BTW, but the same problem. I was installing point of sale units (interactive computers) in white goods stores. (white goods=washing machines to you and me), The POS system had a laser disc system in it and a small microcomputer to control the keypad and run the laser player. 99% of the shops, the POS system worked fine but in some it didn't and only worked when the system was restarted. To cut a long story short, what was happening was when the POS system was switched on, it was being switched on with the shop lighting in one go, and it was all fluorescent lighting which was causing lots of noise and crashing the microcomputer(due to poor mains filtering). A cure was to put a delay in the microcomputer initialization to miss all the mains noise from the lighting coming on.

[v6en]

Well, we phoned my mate's garage and asked him how he got it to start...his answer was full throttle and then turn the key like you said. the problem of course was that the battery was starting to go flat by our 11th attempt lol, so i had an epiphany and rigged its battery up to my S40's while we cranked it over some more. when i had almost given up hope it started! yey! took it a big long run and it's been fine since.

we think what may have aggravated the prob was that ross was going to take it to work that morning and it was -5 degrees outside, he turned it on, noticed the petrol light come on, and switched it straight back off again, so it was probably a bit flooded as well as bleedin cold when later on that day i then came out and it wouldn't start.

thanks for the advice, and i'm glad i didn't have to push it or bump start it in reverse lol.

jacq.

My 850 M reg just wont start when its cold.VOLVO garage have plugged it on there lie detector.I have replaced the dissy cap , all leads a few expensive sensers, now I have replaced the coil .Is this a common fault.The car has done more miles than the cast of Star trek, surely this wont be the end of it will it.Is it RIP OR YIPEE!
Let me know folks !
Wurzel