Stuttering on start-up, then runs fine

vindemiate · Post by **vindemiate** » 25 Nov 2017, 16:56

Hello All,
I'm new to the site yet have been using its resources for some time now. I own a 2005 S80 2.5t (late model) that has been having some stuttering issues upon start-up. During normal driving, stop and go traffic, freeway, etc there's been no issue. On occasion, that seems to be occurring more often, the car will stutter on start-up. It starts at about 700RPM then drops below 500RPM and fluctuates for a few seconds. If I press the gas peddle, it revs and other times it acts as if it disconnected the peddle from the engine and nothing happens. After no more than 15 seconds or so, it seems to run fine.
All new plugs
One new coil pack
New MAF
Cleaned throttle body
New fuel filter
New air filter

Thanks for any assistance

rb61 · Post by **rb61** » 27 Nov 2017, 09:33

This is exactly what my 2001 S80 started to do yesterday. After a shut down, it starts immediately and runs well. I am beginning to think it may be a loss of fuel pressure when the car is not running. I will let you know if I find out more.

rb61 · Post by **rb61** » 27 Nov 2017, 19:21

Update- I have no idea if this should work, but it got me through the day and a 40 mile trip.
I turned the key to just before start- you should hear the fuel pump hum. Turn the key to off and try to start. This worked 4 times today. It may just be that there was not enough down time to lose pressure or who the hell knows...

I will try this in the morning after the car sat all night.

If nothing else, this type of experimenting and information gained may reduce the time spent on diagnosing the problem at dealer rates.

rb61 · Post by **rb61** » 28 Nov 2017, 20:26

I activated the fuel pump 2 times before each start (8 or 9) today and it worked perfectly.

I will bring it in for service later this week. One mechanic felt that it may be a non return valve in the fuel pump.

vindemiate · Post by **vindemiate** » 29 Nov 2017, 11:21

That’s pretty interesting; I’ll give that a try. One thing that I’ve noticed is that I don’t ever have a problem when the car is cold. Wonder if that has something to do with the higher startup idle.
My issue usually happens after driving and getting the car to temp then stopping at a store or the like. But then again, when I jump in the car, I just start and go. I’ll try the slower approach to see if it makes a difference. Fingers crossed.
Now for the danged headlight issue. That’s for another thread though.

rb61 · Post by **rb61** » 09 Dec 2017, 21:34

A new CVVT solenoid solved the problem on my 2001 S80.
$140 at Rockauto and 15 minutes installation.

Ths replacement seems to have eliminated a few other error codes- Oxy sensor and MAAF- which I have been told is not that unusual. Time will tell if they are really gone.

http://www.rockauto.com/en/catalog/volv ... ator,12910