I have a '93 model 90, six cyl. that wouldn't start. Replaced the ignition control module, plugs and plug wires. Now it seems to start when cold, but not hot. Does this sound like crank sensor? If so, can anyone tell me where to find it, and if I can test it?
where is the crankshaft sensor? on 1993 Audi 90
by needhelp93 in La Grange, KY on May 14, 2009
ANSWER by spyder , May 14, 2009
This car has very basic self diagnostic features. You put a fuse in the open slot on the fuel pump relay to initiate a flash code sequence , like morse code. The results may indicate where to start looking. A basic tutorial is here http://www.google.com/url?sa=t&source=web&ct=res&cd=2&url=http%3A%2F%2Fwww.autolib.diakom.ru%2FCARS2%2Fpribor%2Fcs1000%2Fmanual%2Fvw_blink.pdf&ei=uaAMSpSRL42Ntgf7-bmBCA&usg=AFQjCNEoaOQyQ-T_K5xG5O7FGZwjzYnoLg&sig2=RkeGRJq6kJbq5f0rDYy8vw As far as where the crank sensor is , follow the wires from the grey connector on the firewall , drivers side. If it won't restart hot you may have residual fuel pressure issues.
ANSWER by dandd , May 14, 2009
When you crank it, do you have spark and/or fuel? Here are 2 ways to test for these things. To test for spark, find an old spark plug and use one of the wires and place it into the spark plug connector. Then use a jumper wire to connect the ground electrode to an engine ground and have a friend crank over your engine. DON'T HOLD THE SPARK PLUG BECAUSE YOU CAN GET ONE HECK OF A SHOCK! Just lay it on the engine. There should be a snapping, blue-yellow spark that is rhythmic. If there is spark, then you can check for fuel. This is easy in that you can just spray some carb cleaner into a vacuum port and see if the engine fires off, at all. I mention this because the crank sensor controls both spark and fuel. If you have neither spark nor fuel, then I would test the crank sensor with an ohm meter. The Crank Sensor is usually located somewhere on the bell housing and typically has 2 wires. The readings should be around 200 ohms. If it is in the thousands of ohms, then that is usually a problem.