[NateDawg]

Ok,

I think i realize why my 2002 Ford Taurus DOHC has been running rich. I believe i may have a vacume leak some where. I hear a slight hissing but i am not sure if it is air being pulled through the upper intake manifold, or if there is a gasket that didnt properlly seal, or if a hose has a slight crack in it.

Normally, is there a slight hissing sound coming through the intake manifold, or does that mean that a gasket did not seal properly? I had a friend preform a tune up last summer and we had to remove the upper to get to the back plugs.

 

[wjc]

Ok,

I think i realize why my 2002 Ford Taurus DOHC has been running rich. I believe i may have a vacume leak some where. I hear a slight hissing but i am not sure if it is air being pulled through the upper intake manifold, or if there is a gasket that didnt properlly seal, or if a hose has a slight crack in it.

Normally, is there a slight hissing sound coming through the intake manifold, or does that mean that a gasket did not seal properly? I had a friend preform a tune up last summer and we had to remove the upper to get to the back plugs.

It's not a quiet engine, but no there shouldn't specifically be a "hiss". Common causes are intake gaskets and/or PCV hoses.

 

[NateDawg]

Hissing Sound

I am not sure if it is a "hissing" sound of it is is the sound of air going through the UIM.

I am tempted to have the gaskets replaced along with a PVC valve and hose replacement when the UIM is removed.

The plugs have a ton of carbon build-up on them from my car running rich. I only had the tune up done last year and i was very suprised.

 

[NateDawg]

PVC Valve hose

Is this the PCV valve hose that i should be replacing? Its only $13 from rock auto, so i am not breaking the bank on this purchase.

 

[gvk]

Is this the PCV valve hose that i should be replacing? Its only $13 from rock auto, so i am not breaking the bank on this purchase.

Yes this is .Also check the rubber elbows at the and of plastic hoses that go from the intake to both valve covers.The front valve cover is easy, for the back one the best way is to remove the cowl.

But most likely it is the PCV hose.

 

[crackhead]

From a previos posting related to the topic.

I suggest doing the PCV valve and intake gaskets while you have the UIM off since they are cheep and you have everything apart.

Intake Manifold Gasket Fel-Pro MS92586 $ 14.00
PCV Motorcraft EV-243/YF1Z-6A666-AA $ 10.41
PCV Hose Motorcraft YF1Z-6A664-AB $ 13.45

The price are from RockAuto. The prices are way cheaper then the local dealer and arrived quicker then the "Special Order" time from the dealer.

The Intake Manifold Gasket will come with the a new EGR gasket. Also have on hand some vac tubing and and replace the hard to reach lines while you have the intake off.

The wiki has a some info on the PCV replacement. Gen 4 24V Simultaneous Codes P0171 and P0174 Solution - Taurus Car Club Maintenance and Modification Wiki

The "new " hose will have a reinforced 90 deg bend.

 

[NateDawg]

PCV Hose

I haven't changed the PCV valve or hose yet, but i plan to do it soon. I just need a weekend of 60 degrees or more. However, i was able to put my hand on the pcv and slightly wiggle it. I did hear the hissng sound get louder when i slightly moved the pcv hose.

Does this vacuum leak cause fuel effecieny problems?

After this is done, i plan to look for someone who has a scanner that can read "live data".