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

[misha]

No lighter!
For Map you measure voltage while applying a vacuum to it's vacuum line and voltage at rest.
YouTube have a lots of videos on how to check Map sensors.

For IAT you measure resistance,just like for ECT.

[Krisemann]

Is that black silicone...holding a vacuum tree?

My stepdad helped me with fixing that after the bolt head simply broke right off when I borrowed his garage while we were checking the vacuum lines (I'm very dependant on my car to get to and from work, so we didn't have the time to fix it in any other way). The screw hole on the intake manifold is completely broken - I plan on getting a new manifold once I can afford it. The stuttering was there before that happened though, so I don't think that's the problem, as it should completely seal it.

Where that white vacuum line goes to?
Fpr is at fuel rail....that line should go at the opposite side!

I don't know why that goes in front, but it's always done that, we haven't changed it in any way, only cleaned them. It's been like that since before the problem, but there's been several different solutions on my car compared to a lot of other 850s, like the PCV which I mentioned earlier. Seems like you're right though, looking at the chart. The woman who owned the car before me never did anything herself on that car, so must've been a mistake at a mechanic a long time ago.

[Krisemann]

No lighter!
For Map you measure voltage while applying a vacuum to it's vacuum line and voltage at rest.
YouTube have a lots of videos on how to check Map sensors.

For IAT you measure resistance,just like for ECT.

Alright, thank you. Will look into it tomorrow once I get myself a multimeter

[misha]

Post a picture tommorow where that white vacuum line goes to the front.
It should go to MAP at fan shroud.
Also...check FPR vacuum line where it goes...it should go to a vacuum tree at the opposite side of that white line....and should also be white.
FPR is at fuel rail....between 1st and 2nd injector...or maybe beween 2nd and 3rd according to that diagram.
According to that diagram....you should have EGR.

[misha]

That broken bolt can be extracted with extraction drill tool....no need for a replacement manifold.
Extract it and put in a new bolt.

[Krisemann]

That broken bolt can be extracted with extraction drill tool....no need for a replacement manifold.
Extract it and put in a new bolt.

Trust me, we've tried. The extraction tool broke as well, and that was much harder to drill through. I might have to bring the whole manifold to a workshop, but at that point getting a used one might be cheaper here.

According to that diagram....you should have EGR.

It's not there, we've checked. I suspect it might have been made ready for EGR, but never installed. If it had been deleted it'd fail on MOT as well. The diagram also lists some other electronics which the car doesn't come with, since the vacuum tree has just had most of its holes plugged with caps.

[Krisemann]

The upper line goes from the front end of the vacuum tree and to the FPR. Lower one goes to what I assume is the MAP.


Closer pic of where the lower line goes to. I guess that's the MAP then?

Oh, I should also mention that the IAT didn't sit properly. It was also dirty from oily residue as well.

[misha]

Fpr line is routed with a shortcut.

That on fan shroud could be MAP but i can't see because of it's shield(carrier).
Can you take it out of there?

IAT could be saved.
If it's covered with oil residue it can't sense incoming air temperature.
Try to clean it with a tooth brush and some alcohol from the farmacy....just regular one for desinfection...you probably have it at home.
Clean it gently....because there is a simple resistor with fragile little legs.

After cleaning,dry it well and check it with multimeter.
After that we will proceed further.

[Krisemann]

Alright, I've cleaned it off with hand sanitizer, waiting for it to dry now.

That on fan shroud could be MAP but i can't see because of it's shield(carrier).
Can you take it out of there?

Was attatched to a panel above the fan with 2 T25 screws.

[misha]

Can that metal casing be removed?
We need a part number for verification.

It have 3 pin connector(common for MAP) and a vacuum line which goes directly to intake manifold.
What you mean by hand sanitizer?

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