Mongo

I noticed on the 944 while changing the spark plugs tonight that there is a vacuum line that was connected to a fitting the broke just below the number 4 manifold tube. It is right next to the #4 spark plug too. It looks as if it deteriorated by heat. the line appears to run from the cylinder head to a heater valve, but the vacuum line looks like it runs to the area where the master cylinder is. i took the car out for a drive and nothing seemed to be wrong or disoriented from the severred fitting and hose. just for the record the fitting that broke on top of that valve is the closest one to the firewall. anyone know what this is and what it connects to? BTW I checked to see if the heater was affected and it still blows *** baking hot.

Cass944

i think like 2 of my vacuum lines are actually even hooked up. my heat and everything works. I dont even know wtf they do...

Mongo

don't you mean aren't? I think those might be the same lines.

Anyone wanna try their luck???

Charlotte944

That vacuum line is used to control the evaporative emissions purge system.

The part under #4 intake runner is a temperature operated vacuum switch that is set to open when engine coolant temperature reaches 58 degrees Centigrade.

Vacuum comes from the front most port on the throttle body, and is applied to the therm-switch just as the throttle plate starts to open. From there the vacuum "signal" opens a valve which "purges" the charcoal cannister.

HINT: There should be a vacuum diagram on the passenger side wheel arch just above the windshield washer tank.

craig001

If anyone needs the vacuum line/EPA diagram sticker for a 1986 944, drop me a line. $13.50 delivered. I bought the wrong one. I put mylar hood protectors on my S2 and covered up the sticker. Didn't read the description carefully before buying this one. Ooops.

Mongo

if the vacuum line is severed will this mean that the emissions purge system is disabled and that my car will fail smog? Will this also cause any loss of power?

Charlotte944

I would not expect to see a significant loss in power. You will have a vacuum leak. Depending on how **** your local emissions standards are the vehicle may not pass inspection.

Charlotte944

I just checked my owner's manual, and I think I owe you an apology.

From looking at the diagram on page 103 (This is for my '87), if the control valves fail, the engine COULD be running lean.

This is possible because the purge system connects to the intake tract between the Air Flow Meter and the throttle body, so that any additional air drwn through the purge system is not measured by the AFM, and is not "seen" by the DME.

SidViscous

Had a vacumn line missing, hooked it up and got noticeably more power. I would recomend getting them all on if you can.

Between that and grounds My Gomorah is running smooth as glass nowadays,

Mongo

84 cars are different than 87 nas in some aspects. 85.5+ do not auxilary air regulators and that the car will idle improperly if it has failed. The regulator is not busted but the idle is now not as high as it used to be i noticed. I guess its because of this vacuum leak.

I will take some pictures of the 2 (one is broke) vacuum lines connecting to the fitting under the number 4 tube on the intake manifold. Perhaps we can identify it by picture.

Mongo

Hey does anyone have a PET program or schematic of any vacuum lines under the intake manifold. i can point it out if anyone has one.

if not.... worth a try...