Volvo 850 engine stuttering at low RPM, not sure why?

Krisemann · Post by **Krisemann** » 27 May 2020, 14:27

misha wrote: 27 May 2020, 14:23 What you mean by hand sanitizer?

It should be clean alcohol....without leaving residues.

Yeah, bought it at the drug store. I believe it's a combination of alcohol and isopropanol, but both should vapourize.

I think the metal casing comes off, will try.

Krisemann · Post by **Krisemann** » 27 May 2020, 14:45

And presto, out of its cover. The number is 876 4214.

Post by **misha** » 27 May 2020, 14:53

Yep...that's the MAP!
http://www.bildelsbasen.se/?link=item&s ... d=24973327

This is how to test it:

Instead of vacuum pump,you can create a vacuum with your mouth and use the vacuum line side from the manifold.

Krisemann · Post by **Krisemann** » 27 May 2020, 16:28

I don't seem to be able to get any contact, I tried sticking a metal pin into it like shown in the pic but I don't get any readings. I suppose I need to find a longer metal wire somewhere, but I'll have to do that tomorrow, though I pushed it far enough in to the point where it hit something solid?

Post by **misha** » 27 May 2020, 16:52

Key in pos.II?

Krisemann · Post by **Krisemann** » 27 May 2020, 16:55

misha wrote: 27 May 2020, 16:52Key in pos.II?

Yep, obviously

93ForMe · Post by **93ForMe** » 27 May 2020, 18:16

Krisemann wrote: 26 May 2020, 17:29 This is very common. From a cold start the car runs for a few minutes, then once the engine heats a little bit the stuttering begins. Usually happens at around 2000-3000rpm (so when I start from a complete stop or when I drive at a steady speed on the motorway).

Does the problem go away once the car is full up to temp after 20 minutes or so, or will it persist through a long drive?

Richard99 · Post by **Richard99** » 27 May 2020, 22:57

Clean the air idle control valve.

Krisemann · Post by **Krisemann** » 28 May 2020, 05:42

93ForMe wrote: 27 May 2020, 18:16 Does the problem go away once the car is full up to temp after 20 minutes or so, or will it persist through a long drive?

It used to work smoothly once the temperature stabilized, but this only happened if I let it idle (the engine refused to get to work temperature when I was driving, especially when the weather was cold). It also ran perfectly when the O2 sensor was plugged out, but now it's struggling even when the O2 sensor is disconnected (though less than when it's connected).

Richard99 wrote: 27 May 2020, 22:57 Clean the air idle control valve.

Hmm, idle is fine though, unless I plug in the O2 sensor. I'll look at it anyway

Post by **misha** » 28 May 2020, 06:05

Did you checked IAT values with multimeter?

Once it checks ok....we will proceed to MAP.

If it is ok....we will attack FPR.

If all of that checks out ok....then your brand new o2 is bad(it happens) or you have a vacuum leak which needs to be fixed and which can affect ALL related sensors and fpr.