[:@] I am getting super frustrated with the 1993 cabriolet I purchased recently. I bought the car and did these things to it because it didn't run properly:
1-replaced the spark plugs/wires
2-replaced the fuel filter
3-replaced the thermostat
4-replaced the fuel-pressure regulator
5-changed the oil/oil filter
6-replaced the ignition core (?-not sure this is what the mechanic was talking about)
7-changed the air filter
8-replaced the muffler/exhaust under the car
9-replaced a vaccum hose on the engine

Sooooo....the car still runs about the same which is not good and seems to be temperamental. Let me explain its symtoms:
1-doesn't want to start after it gets hot
2-hesitates, sputters at low rpm, levels out at higher rpms
3-runs rich, puffs black smoke
4-seems to flood itself out and will not restart
5-not related to the previous but the blinker indicator light is on but the blinkers will not work

occasionally the car does fine and not all symtoms are present, but at other times they are all presented, please let me know if you can offer suggestions of how to fix my car, affectionately known as my "Black Hare"
Thanks!

 

Hi!

I have a 92 Cabriolet and I hade one symptom similar to yours. It's the black smoke puff. I replaced the oxygen sensor and it fixed it. Also you have to make sure all the ground connections in the engine compartment are good including the oxygen sensor's.

Also when it doesn't want to start when it's hot does it crank or does not?
If it doesn't crank it's common that the starter gets hot thus all the wires have high resistance which leads to insufficient current flow. Solution thicker wires or some kind of heat shield around starter and wires.

Also could be your ECU too but that's the worse case.

Hope i helped you some.

Peter

 

Oxygen sensor was the first thing I thought of also when I read the list of problems.

Not turning over could be battery cables or starter.

Do you have engine check codes to point you to a place to start?

Don't feel to bad about your car. Click here to read what I went through recently

 

The troubleshooting section of my Haynes manual does mention the battery cables as being a possibility.

However the "Engine hard to start when hot" list of causes and the "Engine misses at idle speed" list have the following in causes in common:

Problem with fuel injection system

and/or

Uneven or low cylinder compression

Testing cylinder compression and electrical connections to fuel injection requires special tools. Some simpler checks on the fuel injection system are:

1. Take the car to Auto Zone to check the battery. Pick up some throttle-body cleaning spray while you're there.
2. Your air filter in new, but check it anyway for clogs or obstructions
3. Check your fuses. If you have one that is blown and keeps blowing out when you replace it, your have a short in your wire harness. In my 2001 the fuel pump/oxygen sensor fuse is #18. That's the 18th counting left to right. I don't know what it is on yours. You should research this. Maybe someone reading will know.
4. Remove the air intake duct from the throttle body and check for dirt, carbon, or other residue build-up. If it's dirty clean it the throttle-body spray you picked up at Auto Zone. This is actually a very common problem on Cabrios. The throttle mechanism gets gunked up and doesn't adjust the air flow properly. This is one of the first things I did on my daughter's Cabrio. For cleaning see this popular mechanics article.

If those don't work you need someone familiar with the wiring grounds, a volt-ohm meter, automotive stethoscope, a "noid" light or maybe someone who can check your ECM.

On another car I'd advise replacing the signal relay (for your blinkers), but I'm new to the Cabrio, and nothing I have indicates one exists let alone where it is located.

 

I have a 1986 Cabriolet and had many of these problems as well. Like the person said above much has to do with the oxygen sensor. I also had the trouble idling after the car had been restarted when hot was cause by my vacuum storage tank being bad according to my mechanic. This part is rare and nearly impossible to find so the car has to have the oxygen sensor and idle tuned. I also just had 3 of my O-rings replaced which seemed to help. Find yourself a good vw import mechanic which i did

 

Okay I'm not sure if your 93 has one but I can tell you the Mass Air Flow Sensor will create those exact problems with the misfires and rough running at low rpm. We have 3 (a 95 and 2 97s)with the 2.0 engine and 2 needed the MAFS replaced because similar running conditions. Good luck with it.