IPD sale XeMODeX - Experts in Volvo Electronics Free shipping all USA - Experts in Brakes
Did you know? 🤔
Logged in users can get email notification of topic replies Log in or register (free).
Amazon Link Buy anything with this and it helps MVS!

2007 XC70 does not start in cold temperature (battery is good)

Help, Advice, Owners' Discussion and DIY Tutorials on Volvo's stylish, distinctive "P2" platform cars.

2001 - 2007 V70
2004 - 2007 V70 R
2001 - 2007 XC-70
2001 - 2009 S60
2003 - 2007 S60 R

User avatar
abscate
MVS Moderator
Posts: 20432
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 283 times
Been thanked: 894 times
Trinidad & Tobago
abscate

Re: 2007 XC70 does not start in cold temperature (battery is good)

Post by abscate » Thu Jan 23, 2020 11:08 am

Here is the cheap diagnostic next time the no-start occurs

A three second blast of starting fluid (ether, or di-ethyl ether, same thing) into the snorkel, followed by cranking, will tell you if you have a cold induced fuel delivery problem.

If it suddenly breathes fire on ether, then your fuel is not getting delivered properly.
These users thanked the author abscate for the post:
GabrieS
Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW
Link to Maintenance record thread
Link To Volvo Glossary

h20ham
Posts: 71
Joined: Sat Feb 23, 2013 10:06 pm
Year and Model: 1998 xc
Location: bc
Has thanked: 0
Been thanked: 0
Canada
h20ham

Re: 2007 XC70 does not start in cold temperature (battery is good)

Post by h20ham » Thu Jan 23, 2020 11:11 am

Methyl Hydrate. Run tank empty
68 125 b18 4 speed
72 164e b30 5 speed
79 242 16v 5 speed
84 744 T 5 speed
86 745 T 5 speed
88 765 T aw71
91 745 T 5 speed
95 965 T shift controller in progress
05 xc90 rough idle

GabrieS
Posts: 19
Joined: Fri Jan 10, 2020 2:02 am
Year and Model: 2007 XC70
Location: Greater Toronto area
Has thanked: 2 times
Been thanked: 0
Canada
GabrieS

Re: 2007 XC70 does not start in cold temperature (battery is good)

Post by GabrieS » Thu Jan 23, 2020 12:18 pm

That sounds like a good simple test.
What is the snorkel in my case?
Where would I spray the starting fluid?

h20ham
Posts: 71
Joined: Sat Feb 23, 2013 10:06 pm
Year and Model: 1998 xc
Location: bc
Has thanked: 0
Been thanked: 0
Canada
h20ham

Re: 2007 XC70 does not start in cold temperature (battery is good)

Post by h20ham » Thu Jan 23, 2020 12:34 pm

Open air filter. Starts there
68 125 b18 4 speed
72 164e b30 5 speed
79 242 16v 5 speed
84 744 T 5 speed
86 745 T 5 speed
88 765 T aw71
91 745 T 5 speed
95 965 T shift controller in progress
05 xc90 rough idle

dwwalker
Posts: 7
Joined: Tue Apr 16, 2013 11:15 am
Year and Model: S40 2001
Location: Hamilton
Has thanked: 0
Been thanked: 0
Canada
dwwalker

Re: 2007 XC70 does not start in cold temperature (battery is good)

Post by dwwalker » Mon Jan 27, 2020 9:54 am

I used some aluminum foil to shield the wire going to the crankshaft sensor but it's not easy and I don't know how effective it is.
Yesterday I changed the starter and put on a Bosch rebuilt unit. Waiting for cold weather and I will post the results.

User avatar
mrbrian200
Posts: 1552
Joined: Wed Jan 20, 2016 8:47 am
Year and Model: 2006 S60 2.5T FWD
Location: Northern Indiana/Chicago
Has thanked: 7 times
Been thanked: 80 times
United States of America
mrbrian200

Re: 2007 XC70 does not start in cold temperature (battery is good)

Post by mrbrian200 » Thu Jan 30, 2020 12:49 am

I have doubts as to how effective simply wrapping the wires with foil might be.

The following is more a 'thought project' rather than a concrete theory or diagnosis (that would need to be based on direct observation on a vehicle experiencing this exact problem). So don't get too crazy about going down this path until you've exhausted other likely/easier to address possible causes.

I'm not debating the effect (magnetic currents being induced in the pigtail/wiring). I'm questioning Volvo's assessment of the 'culprit' ie what's actually 'broken' that either results in unwanted currents in the wiring, or, normal induced noise, present in every vehicle, not being filtered out before the analog to digital sampling of this sensor signal within ECM.

The foil would need to be grounded otherwise the faraday effect/interference rejection is likely to be minimal except for very high frequency--approaching radio frequency - interference. Which isn't likely what would be produced by a starter motor. Or it's spike/arcing noise (think along the lines of atmospheric lightning disturbing AM radio reception) due to degraded/broken wire insulation in the motor windings, the arcing noise normally associated with brushes in a high current DC motor. Good windings would produce a mid frequency cyclic 'square wave' magnetic interference something well below 1khz. Which notably would be within a similar frequency range that the crank sensor signal 'operates'. If there's excessive interference between the starter motor and the crank sensor I really lean toward an internal issue within the starter motor rather than the mating between the engine/trans as the Volvo TSB seems to indicate. Remember as temperatures drop, the starter motor pulls more current. Hence a stronger magnetic fields will be generated potentially picked up by either the sensor or sensor wires. With increased current, the noise produced by DC motor brushes would also increase. The faraday effect between the engine-trans doesn't necessarily need absolute electrical continuity across the entire mating surfaces to work. Frankly the 8 or 10 bolts that hold the engine-trans together - where electrical/magnetic continuity would never break, should be enough to get these two parts to behave as one in this respect considering, at worst, they're sit very, very close together.

It's also reasonable to deduce that the ECM may utilize some sort of EMI/RFI choke on the front end of it's internal circuitry that samples the crank sensor signal current. The purpose of which would be to filter strong radio and/or random noise interference that could be induced in the wiring like an antenna (such as the arcing noise you'd expect from the brushes in a high current DC motor inside a perfectly good, brand new starter motor).

The Volvo TSB, likely derived from an 'inventive' dealer or regional tech, is probably as much an unproven hypothesis as anything I'm proposing. I just don't see them having equipment and methods - in a dealer bay where the car would have been - to actually map and measure EMI/magnetic currents in the metal and airspace in and around the engine+trans housings.

I gots a cousin who works at Argonne National Labs (the particle accelerator just outside Chicago). He might know somebody that could devise an 'experiment' to map this in a real engine bay in a real car (not a computer simulation). And I betcha it would cost a small fortune to do it. In a dealer service bay? To coin a phrase.. Oh Girl, Puh-leese!

I've ran this hypothesis across couple other people experiencing like issues in the past (try replacing the starter motor). As it's somewhat a shot in the dark, it makes sense to try a used starter from somewhere rather than an expensive new starter. The issue is so very rare, if the starter motor is actually the culprit, it's highly unlikely to end with a second starter with the same problem. If it solves the issue, and the used starter is of unknown condition/high mileage, then think about buying a new starter for general peace of mind.

Or it could be a fuel delivery problem. Or a wonky electrical connection somewhere that looses continuity as a terminal pin shifts as the metal contracts a tiny bit in extreme cold. Or even something like a relay. The possibilities are practically endless. For s---ts and giggles also check to make sure all the fuses and relays everywhere are all firmly seated down. I've seen that cause cause an intermittent no start on a P2 XC70, though in that case it wasn't cold weather dependent.

If somebody experiencing this issue ever tries replacing their starter motor, and actually reports back whether or not the issue persisted, Either I'll be able to put my theories to rest or Matt will be overjoyed to have a new article to write/add to the 'known fix' area. "Forget that Volvo TSB, Its the Starter! (or the ECM). Remember to remove the foil when installing the new starter (as an experiment, this would be the 'control').

dwwalker
Posts: 7
Joined: Tue Apr 16, 2013 11:15 am
Year and Model: S40 2001
Location: Hamilton
Has thanked: 0
Been thanked: 0
Canada
dwwalker

Re: 2007 XC70 does not start in cold temperature (battery is good)

Post by dwwalker » Thu Jan 30, 2020 7:30 am

I'm not ready to say it's solved yet but it just stared just fine at -12C and it wouldn't do that before. I'd like to get at least a -15C day.
Some info about the starter. The one that came off was a FoMoCo so I guess Ford Motor Company when they owned Volvo. The motor section was physically smaller in diameter and shorter than the Bosch. Keeping my fingers crossed.

GabrieS
Posts: 19
Joined: Fri Jan 10, 2020 2:02 am
Year and Model: 2007 XC70
Location: Greater Toronto area
Has thanked: 2 times
Been thanked: 0
Canada
GabrieS

Re: 2007 XC70 does not start in cold temperature (battery is good)

Post by GabrieS » Fri Jan 31, 2020 3:27 pm

So I decided to check the basics before I continue with my troubleshooting.
First thing on my list was to check the position sensors. I purchased a one year vehicle specific subscription at alldatadiy.com for approximately CAD 45. I went to see how to check the camshaft position sensor. To my surprise the only information I am provided with alldatadiy.com is to remove the bolt that is holding the sensor, replace the sensor, and reinstall and tighten the bolt. Forgive me for saying that but...that is a mockery. I wrote back to them to ask for the proper and detailed instructions such as how to test the sensor for proper functioning, voltage readings across the pins, proper resistance readings in ohms etc.?
In the meantime and with very little hopes to get more from alldatadiy.com…does anybody have this information about the camshaft position sensor and the crankshaft position sensor for this car?
Thank you

GabrieS
Posts: 19
Joined: Fri Jan 10, 2020 2:02 am
Year and Model: 2007 XC70
Location: Greater Toronto area
Has thanked: 2 times
Been thanked: 0
Canada
GabrieS

Re: 2007 XC70 does not start in cold temperature (battery is good)

Post by GabrieS » Sat Feb 01, 2020 7:55 am

In the same line of thought with checking the position sensors...please consider this scenario...
If the camshaft or crankshaft position sensors were to malfunction for whatever reason...and they would not transmit the correct information to the ECM during the cranking of the engine...my understanding is that the ECM would not allow gas to be delivered by cutting off the
modulation pulse to the injectors. Please confirm if I am correct when saying that.
If I am correct...please speculate to weather the test with spraying Methyl Hydrate in the "snorkel" (air intake) would be relevant.
Let's suppose it's freezing outside and my engine cranks but does not start. I would be spraying Methyl Hydrate in the snorkel as my son is cranking the engine. The engine starts briefly until the Methyl Hydrate burns out. This is telling me the gas is not being delivered by the injectors. I know I do not have a blockage in the gas delivery system as demonstrated in my video showing good gas pressure at the Schrader valve. I also know the engine runs just fine when it is warm outside. This could however mean that the gas is not being delivered because the ECM does not know when to time it and it has cut off the signal to the injectors until it gets proper feedback from the position sensors.
Question: Is my logic sound?
If it is...please..can you provide info on how to test and rule out a bad position sensor, bad wiring to and from the position sensors, bad ground of the position sensors, etc.
Thank you

dj_v70
Posts: 200
Joined: Sat Jul 19, 2014 1:51 pm
Year and Model: v70 2003
Location: ri
Has thanked: 5 times
Been thanked: 18 times
dj_v70

Re: 2007 XC70 does not start in cold temperature (battery is good)

Post by dj_v70 » Sat Feb 01, 2020 5:04 pm

GabrieS wrote:
Sat Feb 01, 2020 7:55 am
If it is...please..can you provide info on how to test and rule out a bad position sensor, bad wiring to and from the position sensors, bad ground of the position sensors, etc.
Take Abscate's advice and use starter fluid. If the car starts for a few seconds and dies, you know the position sensors are good. If the ECM doesn't see them, you won't get spark. Try that first, if that doesn't work, check spark. If spark is good, then your position sensors are likely ok also.
These users thanked the author dj_v70 for the post:
GabrieS

Post Reply
  • Similar Topics
    Replies
    Views
    Last post