94 850 turbo sputters then turns off

z Mr Man z · Post by **z Mr Man z** » 21 Dec 2010, 22:14

First things first, I drive an 850 turbo wagon with about 230k miles.

Just recently my car has had some problems driving. I'll be driving along and I'll notice and feel a sharp drop in rpms. Sometimes I can catch it and push on the gas a little more and it'll rev back up to normal and i can continue on my way. But, if I don't catch it it'll drop down to about 200 rpms and just die. And i can just pull over to the side of the road and it'll start up again just fine. I've also noticed that on average my rpms have been below where they usually are, by about 1,000 rpms sometimes depending on my speed. This also only just started happening with the winter season as well. I'm not sure if it's just a coincidence or if it is because of it. The temperatures are around 40 degrees or less on average if that helps. And it's not in a garage so it gets the weather affects directly.

I've done a little searching around the forum and think it might be associated with the fuel pump or maybe something being clogged or dirty. But, other than that i have no idea. So any help would be appreciated.

Post by **jblackburn** » 21 Dec 2010, 22:27

Those almost sound like prime symptoms of a dying mass airflow sensor. Unplug the connector just after the airbox and drive around for a little bit and see if the car still acts up.

This will throw a check engine light; you can easily clear the code (and check for any others) using the OBDI module under your hood:
http://www.volvospeed.com/CheckEngine.php

z Mr Man z · Post by **z Mr Man z** » 21 Dec 2010, 23:24

K I'll give that a try. It doesn't always happen though so i might need to drive it around for a little while. Would that be bad on the car? Or should i just try disconnecting it, drive for a little bit to check, and then connecting it again? I just don't want to cause more harm that what's already done.

Post by **jblackburn** » 22 Dec 2010, 06:56

No harm in driving it for a little bit - the car will run on a best guess fuel/air mixture since it won't be able to measure the amount of air entering the engine. Just don't mash hard on the gas or it will bog down and shoot black smoke.

z Mr Man z · Post by **z Mr Man z** » 22 Dec 2010, 23:09

Well i would have been very surprised if i could get more than a block. After i started the car i let it sit there for a bit to see what it did and it was fine. Then i went in reverse and it instantly died. Just like it was doing before. It would sputter and die. Also it felt shaky and struggled to rev up when i was in neutral.

Then i tried it with it plugged back in and it ran a lot better.

z Mr Man z · Post by **z Mr Man z** » 26 May 2011, 17:22

So I finally got around to changing my mass airflow sensor. After driving it around for a bit I haven't noticed any changes. It still gets lower rpms than normal and It's died once since the new install. I also am getting this weird thing happening as well. I'll be accelerating and the rpms will drop really low. It kind of has the same feeling as when you're driving a manual car and you're in too low of a gear for the speed you're going and you get that "nose dive" type feeling. I'm not sure if there's a name for that... Any other suggestions?

FCPEURO · Post by **FCPEURO** » 26 May 2011, 17:28

I am thinking it could be fuel related at this point. Could be a bad fuel pressure regulator or fuel pump.

z Mr Man z · Post by **z Mr Man z** » 26 May 2011, 22:00

I was thinking that as well. I read up on some other articles on line and they said it was either the Mass Airflow Sensor or something along the lines of the fuel pump or something dealing with the fuel. Could it maybe be the part that plugs into the Mass Airflow Sensor? Sorry, I'm kind of new to working with cars so I don't know what the name would be...

z Mr Man z · Post by **z Mr Man z** » 27 May 2011, 17:55

So scratch that last thing about the problem not being the Mass Airflow Sensor. Earlier today I was driving and my car started freaking out. I would be pushing on the gas and it would barely have any power. Also I could literally see my rpms bouncing up and down. While idling and while accelerating. So I pulled over and disconnected the Mass Airflow Sensor. And the engine leveled out immediately. Any ideas what this might have been?