2002 XC70 Very rough idling in the morning (COLD)

ibaralf · Post by **ibaralf** » 13 Mar 2014, 11:06

A few days ago my wife complained of a burning odor coming from her 2002 XC70 which has only 107k miles. I can't really figure out where it is coming from, but I think it is more like a fluid odor (like oil). Anyway, the car then started idling very rough in the mornings for about 5-10 minutes UNTIL it heats up a bit. It runs very smoothly after that. I've googled and searched this forum and found some slightly similar questions and their recommendation is

1) Clean/replace Mass Air Flow Sensor (MAF)
2) Replace spark plugs

=> The funny thin is, I replaced both of these just 3 months ago. I also cleaned out the throttle body.

I do know that the PCV system of her Volvo is clogged and needs to be replaced (PCV breather system). Could this be causing it?
Are there any other parts I need to check out?

Any advice is deeply appreciated.

Post by **oragex** » 13 Mar 2014, 14:03

have a look on youtube "chech pcv volvo". btw, fix it asap or the engine is affected. it creates sludge inside the oil pan and destroys the engine. you might also have to remove the oil pan ($$) to clean inside if the pcv passage is clogged, otherwise is useless to replace only the pcv box and hoses - google about the issue on forums.

also recheck all hoses around the engine, one might be disconnected

ibaralf · Post by **ibaralf** » 13 Mar 2014, 16:57

Thanks for the reply. Quick question: do you think the clogged PCV is causing the rough idling when the engine is cold?

Yes, I've been meaning to replace this, but it's a HUGE job from what I've read. (I thought removing/cleaning the ETM was tough).

Post by **oragex** » 13 Mar 2014, 18:14

It is actually not among the symptoms people are describing when the pcv is clogged. I would rather point a leaking hose, especially given the recent ETM job, when some hoses (and even electrical connectors) have to be disconnected. I would check all those around the ETM one last time. And even the ETM fitment. There might be something that lets air leak inside the intake when the engine is cold, then as the metal warms and dilates, it seals back - just a supposition.

ibaralf · Post by **ibaralf** » 22 Mar 2014, 19:34

Problem SOLVED. Just to update this, I waited more than a week to be sure. I replaced the Mass Air Flow (MAF) sensor which was chinese made. Put a Bosch (made in Germany) and it fixed my rough idling problem. My wife has been driving it for over a week with no problem in the morning. Just as I stated before, the problem was when starting the car in the morning, the first 5 or more minutes, the engine sort of 'coughs', where the RPM drops down to around 500 rpms and then back up.

I'm planning on fixing my PCV clogged breather problem and hopefully post a HOW TO, since there doesn't seem to be one for the Volvo 2002 XC70. Thanks.

Post by **oragex** » 22 Mar 2014, 20:34

Good to hear is was an easier fix.