1995 850 Vacuum lines trouble

moacyr · Post by **moacyr** » 31 Oct 2014, 09:44

Hello,

My 1995 Volvo 850 is throwing a P0172 (mixture too rich bank 1) code. I have been checking all the vacuum lines and it seems a bit different than the topic "850 and S/V/C70 non-turbo vacuum lines" on this site.

1: goes to flametrap
2: goes to a valve on top of the radiator
3: goes to FPR

Is it correctly installed?

Besides, there is a small hole on the vacuum tree just below the line that goes to the FPR, is that normal?

Post by **erikv11** » 31 Oct 2014, 10:49

I think someone has jumbled up your vacuum lines. Is there a metal nipple on the end of the intake manifold, like in the vacuum lines topic? What is on the nipple?

About the small hole in the vacuum tree: one of the nipples has broken off. There is your car's vacuum leak, or one of them, there should not be any holes.

Also, does this car have EGR?

moacyr · Post by **moacyr** » 31 Oct 2014, 15:22

erikv11 wrote:I think someone has jumbled up your vacuum lines. Is there a metal nipple on the end of the intake manifold, like in the vacuum lines topic? What is on the nipple?

Also, does this car have EGR?

By end of the manifold do you mean the left end? If so there is no vacuum line or nipple there.

I dont know if it has EGR. Where would it be located?

Post by **erikv11** » 31 Oct 2014, 16:29

Since there is no nipple on the intake manifold, the line directly from the vacuum tree to the flame trap is fine. So probably the lines are not jumbled up, and the only thing you need to deal with is the broken nipple on the vacuum tree.

The EGR valve looks like this:

There is also an EGR solenoid mounted up under the fan shroud. Sorry I don;t have time to search right now.

That vacuum line thread seems to have lost several, recent posts about how to route the lines when there is EGR, that is really too bad!

moacyr · Post by **moacyr** » 01 Nov 2014, 05:23

I was thinking about just to plug the hole with something, because shipping cost is to high for me to buy a small item...

And my car does have EGR. That number 2 line goes to that solenoid on top of the fan.

dumb question: does that small vacuum leak causes high fuel consumption? There is a smell of unburnt gas from the outside when idling.

Thank you very much since then! Great help!

Post by **erikv11** » 01 Nov 2014, 11:47

Sure, maybe if you clean up the plastic and roughen it with sandpaper, you could plug the hole with epoxy.

With that hole in the vacuum tree, air is getting in after the MAF (i.e. there is unmetered air in the engine). So the O2 sensor detects too much air, and tells the ECU to compensate by dumping in more fuel. if it overshoots which is common, then the car runs too rich, leading to excess fuel consumption and the smell of unburnt fuel, just as you describe. It is a common result of a vacuum leak.

moacyr · Post by **moacyr** » 02 Nov 2014, 07:19

I managed to plug the hole with some provisional 3M adhesive. Today I reseted the check engine light and drove to work (about 13 miles). Managed to scan some data

Idling:
O2 Bank 1 voltage was ranging from 0.4V to 1V (a bit unstable)
Airflow about 5-6g/s

Accelerating:
O2 bank 1 voltage had for a few times the same range as idle, but more constant reading (from 0.4 to 0.7V)
Airflow was as higher as deeper the step on the gas

Long term fuel trim: Ranged from 2% to 6% (remained most of the time from 3 to 4%)
Some early readings that I had (before pluging the hole) it reached 12%

How would that readings be doing? thanks!

Post by **hausmeister** » 03 Nov 2014, 09:20

I just noticed that you don't have hose-clamps on the idle air hose... (at least on one side it looks like there was never one on the hose). If they were not just removed on the picture you should put some on there.
Also replacing the vacuum lines in general can help quite a bit, the rubber connectors don't hold up so good.

@Plastic vacuum tree: If there is a volvo dealer near you you can get that directly from them. It is really not expensive.

moacyr · Post by **moacyr** » 03 Nov 2014, 17:14

hausmeister wrote:I just noticed that you don't have hose-clamps on the idle air hose... (at least on one side it looks like there was never one on the hose). If they were not just removed on the picture you should put some on there.
Also replacing the vacuum lines in general can help quite a bit, the rubber connectors don't hold up so good.

@Plastic vacuum tree: If there is a volvo dealer near you you can get that directly from them. It is really not expensive.

yes, I put new clamps on all hoses. The vacuum lines can be replaced using silicone lines?

Buying part from the dealer here is unthinkable. Its too expensive. I'd rather import, but shipping cost is around 60 bucks, and unfortunatelly it is also taxed...