Officially back in the fold...

[Doyt W. Echelberger]

Welcome back, Dave.

I have an 87 5ktq at 278k miles.

Lots of things have made it run poorly over the years.

On yours, based on what you describe, I'd probably suspect a faulty
idle/full throttle switch. I might start by replacing it.

After that, my advice gets kind of long winded. But these are pretty
sophisticated cars.

When I got my 87 5ktq, I read everything on the SJM site
first  http://www.sjmautotechnik.com/   and I got a set of Bentley factory
repair manuals from Amazon.com.

Then I learned to run a computer error code dump. That might be be a good
idea, given your car's many problems. Then you could address all the error
codes that show up. Before doing the code dump, I'd clean up the ground
points in the engine compartment and check all the sensor connections. Then
the code dump would go better.

I'd go over every vacuum line and hose and connection and touch them with
my hands and squeeze and  wiggle them, and feel for soft spots and loose
fits, and I'd give special attention to the crankcase breather hose and the
specially cast rubber hoses the it fits into around the ISV. Then I'd pull
the washer bottle and find and feel the short vacuum hose between the lower
wastegate  chamber and the intake manifold. This hose takes a lot of heat
from the exhaust manifold, and it ages fast, and when it fails the rubber
gets sucked into the engine and all that remains is the fabric cover of the
hose....which looks good but leaks vacuum. And of course I'd pull off the
Michelin Man hose and bend it and test it off the car. I do this stuff
every year.

Along with checking and correcting the vacuum leaks, I'd pull the plugs and
check the color of the ceramic tips, and the gap, and the plug number.  I'd
run the car in a blacked-out dark garage with the hood open, and see if
there are ignition leaks that show up.....you might get a light show. I'd
pull off the dizzy cap and check it and the rotor for tracks, dirt, and
condition.....might change both cap and rotor, and check both ends of each
sparker wire and the central high tension wire. Again, I do this every year.

I'd take out and look at and probably replace the air cleaner element.

My car needed a new idle/full throttle switch. And it needs a dose of fuel
injector cleaner about 3 times a year....Techron.

It ran crappy when the oxygen sensor was failing. And when it had several
vacuum leaks. And when I put the dizzy cap back on with the input wires
mis-aligned where they enter the dizzy. And when it needed new ignition
wires and plugs.

That sounds like a lot of things to do. Maybe you would like to find a
really experienced Audi mechanic and let him get your car checked out, of
you can afford it. But that idle/full throttle switch is famous for making
our cars run badly.

Doyt Echelberger
Ohio   USA




 >>>>>>>>>>>>
At 01:31 AM 2/2/2003 -0500, you wrote:
>HI all;
>
>I did a 900 mile round-trip today and picked up my 87 5ktq. In general,
>things are good, but it has an issue that I was unabkle to find info about
>in the archives. I'm not sure if all (or any) of the following is related,
>but I'll tell all...
>
>1. Not too hard to start when cold, but runs very rough/stalls w/o user
>input to keep it going. I know this alone isn't difficult but read on...
>
>2. Once warm, it ran fine, except the first tiny bit of throttle travel made
>it cut out, as if no fuel was getting to the motor. So if you're moving, and
>you let off the gas all the way, then barely crack it on, you will continue
>to decelerate as if you weren't on the gas at all. THe next nth degree of
>input and it woke up, and seemed to be normal. For about 200 miles, this
>condition was very repeatable, with no other pathology.
>
>3. I stopped for gas. When I restarted, any accel. input resulted in a
>miss/surge kind of thing, and it was independant of accel. position (more
>gas didn't help any more). If you ignore it and try to take off, the car
>bucks as if you were stabbing on and off the gas. Strangely, in gears 1-3 it
>is impossible to make this go away or change, you just slip the clutch/lurch
>along. But when you get to 4th and more so in 5th (more load?) it smooths
>out, becoming more like the first problem I described above. Also, when
>sitting still, if you rev the motor quickly, it seems only to have a bit of
>a miss, but if you slowly feed in the gas, you can replicate the miss/surge
>thing.
>
>Any thoughts on this? I'm sorry for my goofy descriptions, but I wanted to
>characterize things as best I could. There are no other symptoms (alt.
>voltage is good, temp is normal, etc).
>
>Dave Arkle
>DoD #11011
>96 Daytona 1200
>84 V65 Sabre
>67 Buick LeSabre
>87 Audi 5KTQ
>On the hunt for a race bike...