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2008 xc70 cold hard start battles

Help, Advice, Owners' Discussion and DIY Tutorials on the third generation Volvo V70 wagon and XC70 crossover, and second generation S80. Are you an owner? Prospective owner? Get in here and join us! Start a new topic or comment on an existing thread.

2008-2016 V70
2008-2016 XC70
2007-2016 S80

mrscullini
Posts: 432
Joined: Mon Nov 13, 2006 9:26 pm
Year and Model: 05 XC70, 08 XC70
Location: Truckee, CA USA
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mrscullini

2008 xc70 cold hard start battles

Post by mrscullini » Fri Feb 10, 2017 7:14 am

i'm sorry, i know cross post from swedespeed.

96k on the clock. battling the hard cold starts. thinking it was the fuel pump, however, before dropping ~$1500 digging a little deeper.

the symptom is hard cold start by excessive cranking before eventual start. the excessive cranking takes a few seconds. seems to happen after sitting over night. does not seem to be an issue after sitting for a couple of hours or immediate restart.

some fuel pressure readings;

after sitting for a few hours
rail pressure- -11 kpa
fuel pressure- 71 kpa

immediate after start up
rail pressure- 420 kpa
fuel pressure- 500 kpa

at idle (minute or 2 after start up)
rail pressure- 380 kpa
fuel pressure- 460 kpa

after engine shut off, the pressure will drop to the "after sitting" numbers above within about 5 minutes. i have not checked the pressure in the morning. however, i don't think it can drop much more. -11 kpa is -1.5 psi, i assume this is relative pressure. i'm at 6000 ft and absolute atmospheric pressure is approximately 12 psi, so at the rail, i'm pretty close to atmospheric pressure at my elevation.

where i'm going with this i'm beginning to question the fuel pump and/or pressure drop off being the issue. i've got a "fuel pump check" error in vida, no code. however, drilling down in vida, it does indicate corrosion/loose pin on the cem, #c2:76. so a few questions,

1. does anybody have fuel pressure numbers documented for comparison to mine?
2. has anybody had an issue with pins on the cem?
3. how do you remove the cem in this model?



mrscullini
Posts: 432
Joined: Mon Nov 13, 2006 9:26 pm
Year and Model: 05 XC70, 08 XC70
Location: Truckee, CA USA
Has thanked: 0
Been thanked: 0
United States of America
mrscullini

Re: 2008 XC70 cold hard start battles

Post by mrscullini » Fri Feb 10, 2017 11:36 am

new observation, check pressures this morning before start up,

rail pressure- -8 kpa
fuel pressure- 74 kpa

basically a 3 kpa rise. i attribute this to the car being parked on an inclined driveway with the front down. 3 kpa is 1' of h2o, that is close given the density of gas to water.

the car started right up this morning, no excessive cranking. making me question the issue of a check valve in a fuel pump.

can somebody with a p3 and no starting issues check your fuel pressures? this would be great to compare. thanks.



mrscullini
Posts: 432
Joined: Mon Nov 13, 2006 9:26 pm
Year and Model: 05 XC70, 08 XC70
Location: Truckee, CA USA
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United States of America
mrscullini

Re: 2008 XC70 cold hard start battles

Post by mrscullini » Sat Aug 19, 2017 6:37 am

for those of you that may be battling this issue, stepping on the brake will cycle the fuel pump. you can hear the pump run and you can hear the relay cycle under the glove box. seems to be a bandaid.

perhaps old news, thought i would share.



hornetv6
Posts: 7
Joined: Wed Jun 23, 2010 12:43 pm
Year and Model: 2008 V70
Location: florida
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hornetv6

Re: 2008 xc70 cold hard start battles

Post by hornetv6 » Thu Oct 25, 2018 1:04 pm

If you hear the fuel pump running when you first step on the brake. It means the fuel is being sucked back into the tank when the car is turned off. It is only an inconvenience. The cure is a new fuel pump.



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