she starts, she won't run - 1990 200QA (very long)

[Ben Swann]

Dave,

 

Sorry to hear of your plight.  It is something simple for sure - the problem
is finding what is wrong, which is not always so simple.  It is tempting to
throw parts at problems, but better to methodically isolate the problem and
fix it.  

 

Some things to do/try:

1.	Pull the codes - check/perform output tests - takes under 10 min. to
do both.
2.	Check and replace most/all vacuum lines - cheap and eliminates them as
source of problem which sound like a vac. Leak.  Also this invariably result
in one finding the problem while replacing them.
3.	Look for large boost leaks - common culprits are Michelin
Man/Intercooler to throttle-body hose(suspect hole at bottom only visible when
removed); check waffle hose is seated - often they are installed incorrectly
and rear of hose is not seated down on fuel distributor rim.
4.	Thoroughly clean airflow sensor plate and install fresh filter - don't
rely on others to do this, as they will just throw a new filter on.  Any
debris can cause the plate to bind.  This goes along with doing jobs (2) and
(3).

 

Start there prior to looking deeper.  A good 3-4 hours and very likely you
will find the problem.

 

I have complete fuel distributors, line and injectors, but don't recommend
replacing unless you verify this assembly is bad - check it when replacing
airfilter  and cleaning the airflow sensor plate.  Plate should lift easily
using needlenose pliers while fuel pump is jumpered on and injectors should
produce a sqealing noise, proving fuel is being introduced.  Jumper fuel pump
relay by borrowing/using gray/orange fan relay and turning the key on - OR -
output test #1 will turn pump on as I recall.

 

You may need to replace injectors and/or seals, which are known to cause hard
starting, but usually not poor running, unless the injectors are really in bad
shape.

 

Keep up posted and let us know what you find.  Don't throw in the towel - with
a little time and patience, you'll have this figured out on your day off..

 

All for now.

 

Ben

http://www.GTQuattro.com

 

[Date: Mon, 22 Jan 2007 10:43:51 -0500

From: "David Michael" <adavidmichael at gmail.com>

Subject: Re: she starts, she won't run - 1990 200QA (very long)

To: quattro at audifans.com

Message-ID:

      <a8fd8d050701220743v33bcd751t3e6af75cf1774e64 at mail.gmail.com>

Content-Type: text/plain; charset=WINDOWS-1252; format=flowed

 

<snip>

The mechanic also mentioned that "the car should run better than it does. It
build boost way too slowly". They did not have time to address it, so I drove
the car off, the noise was gone and the clutch effort much reduced.

BUT ? the car was hesitating a bit when cold and generally not running at
100%.  As I had some time,  it was warm, and it had not been done in 30k
miles, I replaced the plugs. I also did the wires for good measure. The plugs
were all perfect ? slightly ash covered, but otherwise fine.  The next morning
it finally got cold, and I discovered that the car was quite hard to start.

 

Thinking that something needed tweaking, I brought the car back to the
mechanic to get the cold start problem fixed and have the slow boost problem
addressed. They worked on the car for two weeks, and found that supposedly
everything was all OK (control pressures, exhaust back pressure, sensor
resistances etc) with the following two exceptions: I remembered that I had
not replaced the air filter in a long while, and the mechanic found that the
duty cycle signal from mac-14 to the mixture freq valve was not going rich.

I fortunately had a 2nd mac-014, and upon installing that, car was pronounced
fixed.

 

<snip>

 

They spend another 10 hours on the car (mostly their expense), and decided
that it was the metering head. By this time had lost faith and asked them put
it all back together.

 

I picked that car up over the weekend (after working 5 minutes to get it
started) and  now it won't go more than 40 miles/hr when cold (even under full
boost), it smells badly of something burning (clutch smells), it smokes, and
is leaking both coolant and oil all over my driveway.

 

So they took what was one of the best (in my opinion) remaining 200 QAs in New
England (everything worked ? A/C, windows, event the parking brake) and turned
it into a $50.00 piece of junk. I am now convinced that it is something
simple. The car has gone from rock solid to appalling way to fast fro it to be
something subtle. So I am going to tackle it one way or another.

 

Thanks for listening?.

 

Dave

1990 200 QA - 220K, sadly treated

1998 M3/4 98K

02 MCS 35K]