Oscillating idle during warm-up

[AkXCman]

I’ve had this nagging problem for 10,000 miles on our 01 V70 XC.

There are times during the “warm-up” phase that the idle will fluctuate up and down in a rapid succession and the engine almost stalls. At its worst, the rpm may go up and down 500 rpm and the headlights will dim. At other times the fluctuation is much less noticeable and just appears as a rough idle.

When the car is started from a cold start (overnight), the idle is fine at first. As the car warms up and nearly reaches the normal operating temperature, that is when the idle fluctuation is most likely to occur. When the rough idle begins, if you shift the car into neutral or park, the idle will stabilize to normal.

The problem eventually goes away after the engine and transmission have warmed up, but that can take as long as 20 to 30 minutes when the air temp is cold outside.

The problem was first reported to the Volvo service department at the 10,000 mile service. At that time, the service manager thought that the problem might be bad gas. We have changed brands and grade of gasoline; none seem to have much effect. It appears to be more temperature related than gas related. At the 15,000 mile service, a throttle body cleaning and adjustment was done by the service department. This did not resolve the problem. At 17,000 miles they replaced the throttle body. The problem is still there.

I’m not sure what to do at this point. We only have one dealer in Alaska, so there is no option to take it to another dealer for service.

Is there anyone out there who has had a similar problem and had it fixed? If so, what did they do? The car is driveable, but it sure irritates me that I have to put up with this problem.

[mas71]

I can't say I have experience this, but I have a question:

Do they put additives in your gasolin over there in Alaska?
I.e. etanol to counter water buildup through condensing in the gas tank during the cold season?

Here in Sweden they started doing that last winter, after that I experienced temporary raises in my idle on my previous car a 850 Turbo.

[AkXCman]

In the winter, all the gas stations in Anchorage use an ethanol blend in an effort to improve air quality.  They do not blend ethanol in the summer.  The problem that I have is different from yours as the idle goes up and down in a rapid cycle, from low to high to low to high  . . .

Once the car has warmed up it runs fine, but that can take 18 to 20 miles of driving.

['01 XC]

Had a similar problem... our altenator was going bad.  Had to have it replaced (under warranty).  You may want to check your charging voltage with a volt meter to ensure that you have proper charge voltage at the battery (it is located in the cargo compartment in the back of the vehicle).

Not sure if this is your problem... but it solved ours...

Good luck.

[Hiro's XC]

I would say it is one of these things.

1. Timing sensor on the cam. (variable valve timing)
2. Bad ignition coils. They can do a resistance test to check.
3. There are several sensors that monitor the enging/trans and they or the computer could be bad.
4. Like 01'XC said check the output of the alternator. But I suspect if it was bad it would have failed the battery by now.
5. Have they checked for fault codes? The throttle body has about an inch to do with your issues. For cripes sake the car isn't throttle body injected or carburated. Note to everyone. SKIP the $150 throttle body cleaning the dealer says you need. You don't. UNLESS you do EXCESIVE IDLING.(2-3 hours a day) Then you can get some oil draw past the turbo seals through the intercooler and up into the throttlebody, thus coating it. This should take, ohhhhhh, 100K or so.

Good luck. Call Volvo if the dealer can't resolve it. Period. It is a safety issue.

Jason

[Hiro's XC]

I forgot to add.

In the Chicago area we run 10% ethanol year round and there are no fuel issues. Well, except for the diesel that got mixed into the gas on several tanker trucks last year. 10-15 Amoco dealers got hit on that one. LOTS of cars got new fuel systems from BP/Amoco.

Jason

[AkXCman]

Thought I'd update everyone on my saga. The Volvo dealer in Alaska acknowledges the problem but can't find a solution. They said that the only thing they can do at this point is turn it over to Volvo.

A factory rep was scheduled to be here in October, but then cancelled at the last minute. The next time they will be in Alaska is in January.

I have found that if I move the transmission from D to "geartronic" or neutral the idle oscillation stops immediately, so I'm certain that my problem is in the transmission. The car is driveable as long as I don't leave the transmission in D at a stoplight for the first 20 minutes.

The car only has 19,000 miles on it at this point. What frustrates me the most is that I have had to "live" with this problem for two years.

To be continued . . .

[XCMark]

This may not mean a thing (my lack of technical knowledge has been admitted to elsewhere on this board ) but what you've described was happening to my '95 Maxima (yeah, the wife drives the XC). In the mornings, the idle would be very low, car would "shudder" almost about to die, alternatively, it would race up... in N, it would idle fine. Same at stops, etc. Very sluggish upon accelerating again.

I switched to a higher octane and added fuel injector cleaner in the tank and after 1/2 tank, the low, shuddering idle is gone completely, the acceleration is fantastic again and she's very peppy.  I guess my fuel injectors were dirty.

Your story was similar to mine, albeit in a very different car, I know, but it described almost exactly what I had. Just thought I'd share what solved my problem, for what it's worth.

[AkXCman]

The Regional Volvo reps finally made it to Alaska this week and I had a good meeting with an experienced tech. He drove the car for about 5 minutes, experienced the problem as described and recommended that the valve body in the transmission be replaced. They need to order the part so it will be a few more weeks before we know for sure if this will solve the problem. I've got my fingers crossed.

[John@CdnRockies]

AkXCman, hope they have it fixed. For what it's worth, I had the same experience as XCMark with my Jeep Cherokee. Once they used a cleaner, it ran fine.