Uneven power, smell in the car, lights flickering.

MatDesign84 · Post by **MatDesign84** » 27 Jun 2010, 22:18

Ive had my second 850 GLT turbo for a few months now, been a volvo 850 driver since (2002) I bought my first car, this is my second car. These two problems have me stumped. I have noticed under fest acceleration that the power the car produced is noticeably gaining and losing then all over again while gaining speed, you can literally feel it slightly in your seat. After letting off of the gas I can smell exhaust fumes in the car, but I am almost 100 percent sure I do not have an exhaust leak. I had the codes checked and came out with [ too lean, o2 sensor (which I am sure are connected and one is in the mail) and MAP sensor which I do not know what it is or controls.]

Second problem.
While the headlights are on. If I hit a bump the lights will turn off for a split second. Some times while accelerating the cars dash lights, and headlights will come on and flicker resulting in the "check" light coming on for a few minutes just like normal start up leading me to think the car actually shut off for a moment then turned back on. also I have recently experienced while steering around a harder turn for example a highway off ramp that the music will short on and off rapidly for a few moments then return to normal.

I have owned this car for a short while and although its reliable, I would like to correct these ghost problems. I don't think the owner before me took much care of the car or they have tried to rig something up and have messed something up. Its like the car has a massive short somewhere that affects everything. Please advise.

Post by **FlyingVolvo** » 27 Jun 2010, 23:24

I think the O2 sensor should clear up the intermittent power issues you're having, especially if it's the front one. The front one controls the air/fuel mixture, so if it's on the fritz your car will not run optimally.

The flickering lights could be a couple of things, but is probably relatively easy and cheap to fix. First thing to do is to check your ignition switch. Try jiggling the key in the ignition and seeing if you can reproduce the problem. If that does it, then you need a new ignition switch. They are easy to install and this site has some good writeup.

You should also check the battery connections under the hood. Make sure the battery posts are clean and free of corrosion and accumulated junk. Most auto stores sell cleaning spray which really does work well. Then make sure the cables are tighly connected to the posts.

I hope this helps!

MatDesign84 · Post by **MatDesign84** » 28 Jun 2010, 00:56

I have already done the battery maintenance. Will try the ignition thing in the morning and I will report. Thank you.

MatDesign84 · Post by **MatDesign84** » 16 Jul 2010, 22:43

Nothing when I tried this suggestion. I also should mention when making hard left turns my music stops and the speakers let out a strange noise almost like connecting/disconnecting power noise in very fast frequencies.

Post by **jblackburn** » 16 Jul 2010, 23:44

MAP sensor. It has no real purpose in anything the engine computer actually does. My advice: ignore the code and try to find a used one to pop in there.

It does sound to me like you have an issue with either a loose ground (a big one); look around, there are various ground straps in several places, or a postive battery cable. In particular, I might point at the one on the back of the alternator itself.

The bad smell I think was related to an O2 sensor on mine; if I went around racing the engine, it would smell pretty bad when I got to the next stoplight. I did that a bit today since replacing mine a few weeks ago, and haven't noticed a bad smell once. I also tightened up all bolts on my exhaust manifold, so that too could have done it.

Koltiainen · Post by **Koltiainen** » 16 Jul 2010, 23:45

Ihave same problem, smell and loss power
I change all vacuum hoses, some of them was broken and next i checkout flame trap hoses

MatDesign84 · Post by **MatDesign84** » 22 Sep 2010, 19:45

jablackburn wrote:
MAP sensor. It has no real purpose in anything the engine computer actually does. My advice: ignore the code and try to find a used one to pop in there.

It does sound to me like you have an issue with either a loose ground (a big one); look around, there are various ground straps in several places, or a postive battery cable. In particular, I might point at the one on the back of the alternator itself.

The bad smell I think was related to an O2 sensor on mine; if I went around racing the engine, it would smell pretty bad when I got to the next stoplight. I did that a bit today since replacing mine a few weeks ago, and haven't noticed a bad smell once. I also tightened up all bolts on my exhaust manifold, so that too could have done it.

Thank you for these suggestions sir. I need to get it fixed before the oncoming winter months.