2001 V70XC Cranks but won't start only when engine is Hot

Brent1000 · Post by **Brent1000** » 29 Aug 2013, 18:32

I have a 2001 V70XC with 300,018 miles. I have owned it since 2002 and kept up with maintenance. Starting in the last month the car will crank, but not start. I have read through a lot of the posts here and tried many of the suggestions, but no luck.
Here's my story:
The car will start every time on the first try when the engine is cold (in the morning and after the engine cools completely down). If the engine is slightly warm (for example I drive around the cul-de-sac), it will crank a few times before starting. If it's hot, it will not start unless I crank it for 1-3 minutes...and sometime even then it won't start at all. On occasion it has started after a min or two and the engine spits and sputters and I can smell a slight gas odor as if it were starting to flood, then runs perfect. I have replaced the battery, cleaned the starter "logic" wire, tried both keys, removed and cleaned plug contacts on start inhibitor, tried starting in neutral, and had a Volvo repair shop read the code right after it wouldn't start. No code displayed regarding the issue. The car runs perfect any other time and runs for hours on the freeway....I just can't shut it off if I stop someplace I don't plan to spend 6-8 hours. Not sure this is related, but this week, the temperature gauge stopped working. Thanks for any suggestions.

Post by **precopster** » 30 Aug 2013, 02:04

Strange starting issues with an accompanying smell of fuel may be symptoms of a coolant temperature sensor that has gone out of tolerance.
When this happens the car's computer defaults to a cold value making the mixture rich.

Another area to look at is the fuel pressure. Measurement will require a guage. Pressure at the fuel rail should be in the vicinity of 50 psi or 344 kpa. Measure it after the car has sat for ten or fifteen minutes. It should still be quite high; at least over 48psi. If it has dropped you will want to look at the fuel pump's inbuilt pressure regulator.

Post by **IdahoBob** » 31 Aug 2013, 07:43

Hot Start Probs.....OK, this is an almost shot-in-the-dark (and expensive & time-consuming) something to check....but, how are those fuel injectors? One way they just wear out is that they start to drip when off. Vehicle will start fine when cold because the remaining, dripped, gas vaporizes at start up, just as if the choke is on (I know that fuel injection has no choke, but go with the analogy, OK?), then the injectors spit gas just like they're supposed to when the engine is running. You shut the engine off, drip, drip, drip, now it won't start because the fuel mix is too rich. You crank & crank, the engine sucks out the too-rich fuel mix, eventually it sucks long enough to get a fuel mix that will fire, and you are running again. Had this on a high-mileage GM engine (and at 300K miles on your '01 you are getting on towards high mileage), bought a new set of injectors on e-Bay and it fixed same symptoms. If you're saving dollars maybe buy one and move it between cylinders to see which might be faulty.
Happy Motoring!

Brent1000 · Post by **Brent1000** » 01 Sep 2013, 18:10

Thanks for the comments Mike and Idaho Bob. I have not picked up a pressure gauge yet, but did try some additional things in reference to to the feedback. After running the car for 40 minutes, I shut it off and immediately started it again. I then waited 30 seconds and it started fine. 1 minute and it also started with no issue. After 2 minutes it cranked about three times and started. After 3 minutes, it just cranked, but would not start.

Brent1000 · Post by **Brent1000** » 25 Sep 2013, 07:03

Update: After doing some more troubleshooting and reading, I replaced the Engine Coolant Temperature Sensor (ECT). My temp gauge was reading zero and my fan would stay on long after the car was turned off, even when it was cold and just started to move in the driveway. I purchased a new ECT from the dealer and plugged it in (not installed, just unplugged the old to test) while at the dealership and the car started. I removed and plugged the old back in and the car turned over multiple times....but started?? I swapped the old for the new once again and the car fired right up. Now here's the odd part....with the ECT unplugged altogether, the car still started. I have driven the car and turned it off a half dozen times in the last day, and each time it fired up. I will permanently install the sensor tonight and update if there are any changes. Fingers crossed!!

Post by **igel513** » 28 Sep 2013, 13:49

Hi Brent, did the hard start prob. go away w/ a new ECT sensor?

Brent1000 · Post by **Brent1000** » 04 Oct 2013, 06:50

Yes, the problem was resolved with the ECT sensor and the car has been running like new (well, new plus 300,000 miles... lol). I also replaced the thermostat a few days later just from recommendations.

orbya · Post by **orbya** » 02 Jan 2014, 10:50

Brent, any diagrams on replacing the ECT and thermostat or a link you used? Thanks in advance

Brent1000 · Post by **Brent1000** » 20 Feb 2014, 14:33

Orbya,
Actually the replacement was pretty straight forward. The only thing I looked up was verifying where the sensor was located, which is right under the thermostat. Be careful disconnecting the sensor at the harness, as mine was very brittle and broke. I used Ty-raps to hold the connectors back in place. I'm not a professional, but have done my fair share of repairs and it took me all of about 25 minutes (after I got the 40T bit)

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I hope this helps and I see I'm a bit late replying.