Ray Calvo

In December I had the alternator wiring harness update done to my '95. All seemed fine. The car then got parked in the garage till yesterday, when with the gorgeous spring weather FINALLY in western PA I took it out for a good drive (aka "Italian Tune Up"). All seemed fine until I decided to try the AC. Well, when I hit the AC button, all the vents shut off! From past experience I've found this to be due to a vacuum leak. So, when I got back home I started checking the vacuum lines. There was no vacuum at the solenoid on the air duct just to the left of the fan housing. Tracing back, I noticed that on the 4-way connector near the intake manifold, one of the connectors had no vacuum line tapped into it; the line was open to atmosphere thereby causing a vacuum leak.

The top figure shows the 4-way vacuum connector. The line leading to the right and down was the problem line; it was open and I could find no line that could connect to it. The second figure shows this connector pulled up for better visuals. The shop manual shows this line as just being plugged, so I inserted a machine screw to act as a plug (shown in the photos). Plugging this line solved my AC problems; the ducts work fine now.

The thing that bothers me is why was this plug out to begin with? Is this connector truly plugged off, or is there actually avacuum line connected to it? Curious as to what others have noted on their cars.

<img src="http://boards.rennlist.com/upload/vacuum-1.JPG" alt=" - " />

<img src="http://boards.rennlist.com/upload/vacuum-2.JPG" alt=" - " />

Mr Michael B

Ray,

Since I have my 993 just 50 feet away...

I looked and found that I have a hard vacuum line coming out of that port. It runs up under the main rubber boot on the intake and towards the buried back of the engine.

Any good for ya?

Ray Calvo

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> I looked and found that I have a hard vacuum line coming out of that port. </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Thanks, Michael. Probably not what I wanted to hear since now I got work to do, but will do some more digging.

Is yours a C2 or a C4?

MarkC

Ray,

You may remember I had a similar problem to you had before ie when I accelerate with the a/c on, the centre vents close off.

Just checked my car ('95) and it's the same as your pictures, the lower pipe is just plugged it doesn't go anywhere!

I still haven't got round to fixing my previous problem as a/c is definately not required this time of year in the UK, but it's useful to know that a vacuum leak in this area can causes the problem.

Mark

chris walrod

Ray, it actually sounds like your dealer has some work to do. If I understand you correctly, the A/C worked before the dealer got their hands on it?

I just had my harness replaced and found a cross-threaded bolt at the stay that helps support the A/C compressor. I ended up sorting it out myself. This is why its very hard for me to trust dealers to work on my car.

I'll have a look at mine tonight and get post what I find.

Mr Michael B

Ray,

My 1995 is a C2.

If you want know more about the hose in question, just ask. I will be glad to get your answers or some digital photos.

Ray Calvo

Thanks, folks. Plugging that hose cured the AC problems; on a 70 degree sunny day air outlet temperature is 40 deg F with car sitting idling in the garage.

Michael B., you have a US car and have a line coming off this connection. MarkC, you have a UK car and have this connection plugged. I wonder if it has something to do with US emissions control. I looked thru the parts manual, and the emissions control air injection system has some vacuum connections. Naturally, they don't show where the lines go....

RE the dealer; yes, I dread taking my car ANYWHERE for repairs. Also noticed that the flexible duct leading from the alternator/air fan cooling housing to the heater duct to the left of it isn't installed properly; it's loose. Will try to force that duct into position during the week after work.

chris walrod

Ray, I looked at my car and that hose connects to a hard vacuum tube and disappears under the plenum. Same as what Michael B. said.

MarkC

According to the version of PET I have (v5.50.5) both US/Canada and ROW have a "bolt" (900 312 012 02) blocking the ouptput from the "distributing piece" (928 573 729 02).
The other outlets go to the Intake Distributor, Vacuum Accumulater and Vacuum Shift Valve. These components all appear to be primarily related to the inlet system (air) for the fuel injection but clearly have an effect on the a/c.

My 993 repair manual (the factory version) does not give a good explanation of the how the system effects the a/c operation in either Volume 1 - Fuel System, Electronic Injection OR Volume 6 - Air Conditioning sections.

I'll have to check all connections for leaks before replacing the components involved ie the "Change over valve" called the "Vacuum shift valve" in the repair manual (the part with the electrical connection in Ray's second picture above) and the "Vacuum valve" mounted on the fresh air intake.

Mark

tom_993

Hi Ray,
I have an early ’95 like yours, so I took a look last night. Like some of the others above, I have a connection to that hose. It runs under the intake plenum toward the front of the engine. It looks like it’s going to the area where the infamous air injection pump is, but I can’t tell if it connects to the pump or not. Send me a PM with your e-mail address and I’ll send you a picture I took, showing the direction the hose goes.

Good Luck!
Tom
’95 993

hn

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by tom_993:
<strong>Hi Ray,
I have an early ’95 like yours, so I took a look last night. Like some of the others above, I have a connection to that hose. It runs under the intake plenum toward the front of the engine. It looks like it’s going to the area where the infamous air injection pump is, but I can’t tell if it connects to the pump or not. Send me a PM with your e-mail address and I’ll send you a picture I took, showing the direction the hose goes.

Good Luck!
Tom
’95 993</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Hi Tom, Since you've already took the picture, could you post it anyway if it's not too much trouble.
Thx.

tom_993

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by hn:
<strong>Hi Tom, Since you've already took the picture, could you post it anyway if it's not too much trouble.
Thx.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Sorry, can't post, that function has been restricted to Rennlist members only.

hn

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by tom_993:
<strong> </font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by hn:
<strong>Hi Tom, Since you've already took the picture, could you post it anyway if it's not too much trouble.
Thx.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Sorry, can't post, that function has been restricted to Rennlist members only.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">If you want send it to me, I'll post it. Or is it restricted, too <img border="0" title="" alt="[Frown]" src="frown.gif" />

JimBob Jumpback

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yur fren

Ray Calvo

YAHOO - PROBLEM SOLVED!!!!!

Well, I hope so. Decided to take the air cleaner housing off and dig around behind the intake runners and look for loose vacuum lines. Well, I removed the air cleaner cover and filter, then unbolted the housing mount at the top of the runners. Then tried looking to see how the housing came out, and was unsuccessful on an initial attempt. I then unplugged the large connector on the air flow sensor between the intake manifold and air cleaner housing. Reaching down underneath this connector, I found the end of a vacuum line. This appears to run toward the front of the engine where the greenie-weenie emissions air pump is located. Figured this was the missing line; with some effort I routed it to the 4-way vacuum connector and connected it up. Hopefully, will have another dry weekend to go for a test drive.

Thanks for your help, folks.