850 T5 mystery

[ynnejcantbe]

Hi guys,
ive just bought a 850 T5 which has a strange running problem, it will suddenly just cut out for no reason. When you restart, it will run for a few seconds and cut out again. After 5-10 mins, it will start and all will be well!
The guy i bought it from said he changed the fuel pump relay, but im not sure which one it is [under fuse box?] to check and i can hear the fuel pump running.

Any ideas?
thanks in advance

[XC90GUY]

check route of fuel cables. i had a car where bloke changed fuel pump. he re routed lines near exhaust manifolds as it looked tidy! problem was fuel evaporated in the lines once engine was up to temperature!!!!

[y2blade]

i had the same sort of thing with mine a while back so this might be worth a read http://www.volvoforums.org.uk/showthread.php?t=458...

does the fuel pump prime every time you turn the ignition off and on? turn it on until it finishes priming then off again then on again as before and repeat 20 times , it should prime 20 out of 20 times



also deffo worth asking here http://www.volvoforums.org.uk/index.php

the fuel pump relay is under the inspection cover in the top o/s corner of the engine bay up near the bonnet hinge mech

take the fuse cover off and undo the torx screws to reveal the relays

hth




its the pink one #103

Edited by y2blade on Tuesday 26th August 10:19

[cptsideways]

Also take the idle control valve off the air inlet pip & clean it up & lube the bearing inside it. Mine had got sticky & would do similar strange things. Its under the plastic cover to the right of the head & has a 1" thick pipe from the inlet rubber hose to the plastic injector holder (mind you don't break the end of this part off its crappy plastic!!) The idle air goes in behind the injectors.

Edit just realised yours is a T5 so will be slightly different but it'll have the same part somewhere similar

Edited by cptsideways on Tuesday 26th August 10:31

[ynnejcantbe]

Thanks, I'll give all tips a try this weekend

[ynnejcantbe]

Hi all, I tried the fuel pump relay, but no luk, turns out to be the fuel pump,
well so far anyway, cheers

[ynnejcantbe]

New fuel pump fitted, but has still cut out twice, any more ideas? cheers

[cptsideways]

Idle control valve!!!

[ynnejcantbe]

Ok now its had new fuel pump relay, pump and idle control valve, but now it wont start! Turns over but wont fire. I've tried dizzy cap and arm and coil and amplifier. What now?????

[y2blade]

ynnejcantbe said:

Ok now its had new fuel pump relay, pump and idle control valve, but now it wont start! Turns over but wont fire. I've tried dizzy cap and arm and coil and amplifier. What now?????

try the VOC forum

sorry i'm stumped

[Merlot]

ynnejcantbe said:

Ok now its had new fuel pump relay, pump and idle control valve, but now it wont start! Turns over but wont fire. I've tried dizzy cap and arm and coil and amplifier. What now?????

MAF? What happens when you unplug it?

[mas99]

Does the T5 have a cam/crank sensor? Cutting out when warm or no start when warm would make me think cam sensor.

[ynnejcantbe]

ummm maf?

[cptsideways]

mas99 said:

Does the T5 have a cam/crank sensor? Cutting out when warm or no start when warm would make me think cam sensor.

:Thumbup: Sounds about right too, I have a spare one here if you need one

[ynnejcantbe]

Not sure if it would be crank sensor as it wont start to get warm, but i dont mind trying it, where is the little bugger?

[cptsideways]

ynnejcantbe said:

Not sure if it would be crank sensor as it wont start to get warm, but i dont mind trying it, where is the little bugger?

Its on the cam cover on the right side of the head as your looking at it. Right at the top under a wee cover thingy.

[ynnejcantbe]

You say you have one sideways? how can i get it off you chap?

[cptsideways]

ynnejcantbe said:

You say you have one sideways? how can i get it off you chap?

Drop me an email

[Merlot]

ynnejcantbe said:

ummm maf?

Mass Airflow Sensor. Situated just after the airbox. Plug is on the top and can be unclipped. Will it start with that removed?

[ynnejcantbe]

Crank sensor didnt work, ill try unplugging the maf today!