Help locating vacuum leak

  • Thread starter Thread starter Michael Chiu
  • Start date Start date
M

Michael Chiu

OK, a while ago I posted about my Check Engine light coming on and how the
OBD device codes said that I was running rich.

Now that I have just lost my job, I have time to try to find the leak on
my own, which will save me some needed money.

Someone suggested checking an elbow on a hose somewhere, but I don't know
how to locate that hose. I'm somewhat mechanically inclined, so I hope I
can do the replacement if I'm pointed in the right direction. Maybe I
should take a picture of the engine area and someone can describe it based
on the picture.

Thanks.
Mike
 
Michael said:
OK, a while ago I posted about my Check Engine light coming on and how the
OBD device codes said that I was running rich.

Now that I have just lost my job, I have time to try to find the leak on
my own, which will save me some needed money.

Someone suggested checking an elbow on a hose somewhere, but I don't know
how to locate that hose. I'm somewhat mechanically inclined, so I hope I
can do the replacement if I'm pointed in the right direction. Maybe I
should take a picture of the engine area and someone can describe it based
on the picture.

Thanks.
Mike
Click to expand...

fountainpen sure has a great question!

If you're running rich, you don't have the common vacuum leak. The
common leak on 850s and 70s is in the elbow at the end of the intake
manifold behind the power steering pump, but not all of them have this.
 
Oh man, I did forget to mention my car. It's a 1998 S70 T5.

I'm not sure this makes any difference, but for some reason, my car sounds
a bit deeper than it did before the problems arose. It's sort of like the
sound my 240 was making when the end of the muffler rusted and broke off.
 
Michael said:
Oh man, I did forget to mention my car. It's a 1998 S70 T5.

I'm not sure this makes any difference, but for some reason, my car sounds
a bit deeper than it did before the problems arose. It's sort of like the
sound my 240 was making when the end of the muffler rusted and broke off.
Click to expand...

Aha, there's a clue. An exhaust leak can allow air to be sucked into
the exhaust as well as allowing exhaust out. If this happens upstream
of the oxygen sensor(s), then the ECU can be fooled into thinking that
the engine is running leaner than it really is (too much oxygen in
exhaust = lean mixture). Of course there's no way it can compensate to
get rid of this oxygen. Check for leaks from the exhaust manifold down
to where the oxygen sensors are mounted.
 
I think you were on the right track in helping diagnose my problems. I
took the car to my mechanic today. He did confirm that I had a vacuum leak
due to a big hole in a hose. He quoted me $75 to fix it (parts & labor). I
asked him if it was a difficult fix, and he said it wasn't really, but
since there's not much room to maneuver, he'd have to take out a pump. In
a post preceding this, you had mentioned the "elbow at the end of the
intake manifold behind the power steering pump".

Should I just pay the $75 and be done with it, or should I attempt to try
the fix myself? Can this be done w/o taking out the pump, or would that
only be possible if I had tiny hands?

Thanks,
Mike
 
Michael said:
I think you were on the right track in helping diagnose my problems. I
took the car to my mechanic today. He did confirm that I had a vacuum leak
due to a big hole in a hose. He quoted me $75 to fix it (parts & labor). I
asked him if it was a difficult fix, and he said it wasn't really, but
since there's not much room to maneuver, he'd have to take out a pump. In
a post preceding this, you had mentioned the "elbow at the end of the
intake manifold behind the power steering pump".

Should I just pay the $75 and be done with it, or should I attempt to try
the fix myself? Can this be done w/o taking out the pump, or would that
only be possible if I had tiny hands?

Thanks,
Mike
Click to expand...

I think it's possible, but I've never actually needed to do it. I think
for $75 you should let your mechanic change it, it'll make him happier,
and he'll be more willing to give you a fair shake the next time...
Think of it as an investment in this mechanic, he sounds like an honest
guy.
 
You must log in or register to reply here.
Back
Top