85 Cabriolet problems in bumper to bumper...

Hi guys and gals,

I have a 1985 Cabriolet that will run all day long down the freeway,
but when I get into stop and go traffic, the engine will eventually
begin to cut out. Sometimes I can start it up and drive some more,
other times it won't stay running until it cools down and then
everything is fine. It's almost as if the engine gets flooded. Could
the cold start valve be coming on during the wrong time? I may be
imagining things ( as I was parked along side the freeway this
afternoon ), but I hear a noise under the hood that I don't normally
hear when the car does this.

The car idles fine when cold -- goes up to around 1300 and gradually
drops as the car warms up to 900 or so, occassionally drops below that
and then kicks up temporarily to 1000. ( idle stabilizer ).

I have not troubleshot fuel delivery issues in the past and that's the
one area I'm a bit leery of trying myself. Any ideas of things to
look at or things to try before I take it to the shop?

I wonder if it is something simple like the coil. Stop and go creates
a lot more heat under the hood. Perhaps that's affecting the coil?

On 15 May 2007 22:03:58 -0700, mikedawg@u.washington.edu wrote:

Hi guys and gals,

I have a 1985 Cabriolet that will run all day long down the freeway,
but when I get into stop and go traffic, the engine will eventually
begin to cut out. Sometimes I can start it up and drive some more,
other times it won't stay running until it cools down and then
everything is fine. It's almost as if the engine gets flooded. Could
the cold start valve be coming on during the wrong time? I may be
imagining things ( as I was parked along side the freeway this
afternoon ), but I hear a noise under the hood that I don't normally
hear when the car does this.

The car idles fine when cold -- goes up to around 1300 and gradually
drops as the car warms up to 900 or so, occassionally drops below that
and then kicks up temporarily to 1000. ( idle stabilizer ).

I have not troubleshot fuel delivery issues in the past and that's the
one area I'm a bit leery of trying myself. Any ideas of things to
look at or things to try before I take it to the shop?

Make sure the hot idle is correct with no idle compensation devices
plugged in. Check for vacuum leaks. There should not be any clicks of
idle compensation devices unless you turn on the AC. Well the radiator
fan coming on might cause enough of an electrical load to need to bump
the idle.

Make sure the ground strap from the alternator to the engine is good.
I am not sure if the 1985 had one but it was critical on a 1980-1984
Rabbit. Most straps were frayed and shot after 20 years.

You could remove the control pressure regulator, remove the two fuel
lines and blow out any crud that is in the inlet screen. That would be
an exercise just for amusement. In an old car there may be crud in
there. Have you changed the fuel filter just for good measure?

Have you cleaned the contacts and the wiring harness that plugs in to
the distributor hall sensor?

These are all things I have done over the years when I had a 1984 GTI.
It has the same fuel injection and ignition system.