2008 XC90 3.2 Intermittent hard start & idle

DaveOdie · Post by **DaveOdie** » 07 Nov 2015, 08:42

Once or twice a week, vehicle will appear to have a hard start. Has happened on both cold and warm starts, but much more frequently with warm starting. Sometimes it seems slow to turn over, sometimes a short pause as it turns over (this will usually reset/clear my clock), but as so far it has not yet failed to start.

Always followed by a very rough idle, characterized by both dropouts and surging. Sometimes I have turned the engine off, waited a moment and restarted with no issues, sometimes with less problems, sometimes no change. Often the "Reduced Engine Performance" message appears.

Upon driving I would normally have hesitation in performance at the outset, but I've only occasionally experienced any issues with hesitation after getting to speed and even then only when returning to idle at a stop light/sign.

Not sure if related or not, but in the same time frame I have noticed only when accelerating that engine occasionally makes louder, low-end noise. I struggle to describe it, but would compare it to how a diesel engine sounds at idle. (I hope that's not more confusing than helpful). In this case, the acceleration performance is worse than normal.

OBDII Code P2118: Throttle Actuator Control Motor Current Range/Performance
Have cleaned throttle body
Have replaced MAF
New spark plugs

Since replacing MAF, frequency dropped to once per two weeks, but it's not gone.

Appreciate any suggestions!

thebull · Post by **thebull** » 07 Nov 2015, 11:58

I had similar issue on xc70 2006. Very different car. We changed the MAF sensor and everything was fine after. Anyway.
Check your battery first.
Check electrical connections going to the throttle body - you did this perhaps since you cleaned it.

Otherwise go and by numbers:
1. Fuel Pump - working? Noise? Something erratic?
2. Fuel filter - if not changed do it.
3. Injectors - May be. I don't think so.
4. Fuel pressure sensor - Very possible to make troubles without massage.
5. Camshaft sensor - I don't think so. You will have a massage 100%.
6. Throttle body - You have massage about this unit. It says motor performance. Your problem might be there. I don't know how you can test it.

DaveOdie · Post by **DaveOdie** » 25 Nov 2015, 16:28

Thanks for the checklist based on your experience. Here's where I'm at:
- Battery ok
- Connections to throttle body check out
- no noise or issues with fuel pump
- new fuel filter

.. but have not conquered the problem yet. Based on reading of other threads, i'm wondering about the fuel pressure sensor but will need to dig deeper as I've not played around with that before.

Admit that this one has me frustrated. Any other thoughts/ideas are most welcome!

MrDanVolvo · Post by **MrDanVolvo** » 04 Jan 2016, 18:08

I am having the exact same issue with my XC90. I'm going to have the battery tested at O'Reillys and go from there. Please keep this up to date so I can see what else you have learned. THANK YOU!

DaveOdie · Post by **DaveOdie** » 02 Jul 2016, 09:25

the short story (though long in getting there) is that there has been very simple resolution for all my symptoms. Took it to my Volvo dealer, who went thru 2 techs to troubleshoot the varying symptoms. they decided that the battery voltage was just slightly low, and it was throwing off all the other systems in the car. As soon as the battery was replaced, it's run perfectly since for quite some time. I'll emphasize the "just slightly low voltage" comment - it passed the initial check as being low but "in range". I guess in range isn't good enough to keep this machine in proper working order!