Stock 1990
Probationary Member
- 2
- 1
- Aug 26, 2016
-
Raleigh,
North_Carolina
Factory stock 1990 Eagle Talon TSi with AWD (or as close to stock as it can be with 185k miles on it).
Problem started some years ago. Car would run fine but if it had been running at highway speeds then shut off for about 40 minutes, it would run like it was on three cylinders. If the shutoff time was less than that or more than 4 hours, it would run without any problem. Over the years the ECM was changed and other work was done, but the issue remained and only occurred under those conditions, and was less of an issue in cold weather. As a daily driver to and from work or for long highway trips, it was not really a problem, just kind of drove it in a way that the issue didn't occur, but if I forgot or something happened that made me let the car sit for more than 40 minutes and less than 4 hours, and the outside temperature was warm or hot, the issue would occur. Usually, the check engine light did not come on, but I rarely drove it long in that condition. Routine replacement of plugs and wires had no effect.
Over time, it took less and less to induce the problem, but it was always occur more often in the summer months. Fuel injectors were replaced last year due to a dirt problem when the fuel filter was replaced, and that had no effect on the issue. Occasionally I would have to drive the car on the highway after it sat more than 40 minutes after previously having been run, and if it was driven at highway speeds for about 15 minutes the problem would go away and the engine light would go off. This convinced me that some thing was being affected by the heat and the normal operating temperature of the car was not the issue. (The car has always run at normal temperatures and has never run hot.)
This summer the problem started to occur when driving it on the highway for a couple hours, then getting into stop and go traffic at long traffic lights, etc. Finally, about mid-summer it started to occur after about 20 minutes of driving in any condition. When the car ran like this for some time (usually more than 10 to 20 minutes, the check engine light would come on. Being an ODB 1 car, the local parts places couldn't do a reading for me.
After living with this the better part of the summer, I examined the plugs after a two hour trip at highway speeds with the car running roughly with low power and found cylinder #1's plug was tan, wet and glossy looking while the other three plugs looked normal. That, combined with other people's experience made me think the "running on three cylinders" description was more accurate than I had even suspected. With the car being 26 years old, the ignition coil or Ignition Control Module seemed to be the culprit, thinking that a micro fracture may have occurred that expanded when heated up.
Replaced the plugs, wires, ignition coil unit and the ICM with no useful effect: the problem still occurred after about 15 minutes of driving in the 100 degree heat today and the engine light came on. But the problem went away (and the light went out) after another 5 minutes then the problem came back. This repeated with another 5 minutes of driving. The car was parked for about 20 minutes, and the problem came back as soon as the car was started. Returning home, a bulb from a 6 volt flashlight was connected between pins 1 and 12 on the diagnostic connector to see what the code might be (since the engine light had stayed on), but the flashlight bulb did not light up even once.
What do I look at next?
Problem started some years ago. Car would run fine but if it had been running at highway speeds then shut off for about 40 minutes, it would run like it was on three cylinders. If the shutoff time was less than that or more than 4 hours, it would run without any problem. Over the years the ECM was changed and other work was done, but the issue remained and only occurred under those conditions, and was less of an issue in cold weather. As a daily driver to and from work or for long highway trips, it was not really a problem, just kind of drove it in a way that the issue didn't occur, but if I forgot or something happened that made me let the car sit for more than 40 minutes and less than 4 hours, and the outside temperature was warm or hot, the issue would occur. Usually, the check engine light did not come on, but I rarely drove it long in that condition. Routine replacement of plugs and wires had no effect.
Over time, it took less and less to induce the problem, but it was always occur more often in the summer months. Fuel injectors were replaced last year due to a dirt problem when the fuel filter was replaced, and that had no effect on the issue. Occasionally I would have to drive the car on the highway after it sat more than 40 minutes after previously having been run, and if it was driven at highway speeds for about 15 minutes the problem would go away and the engine light would go off. This convinced me that some thing was being affected by the heat and the normal operating temperature of the car was not the issue. (The car has always run at normal temperatures and has never run hot.)
This summer the problem started to occur when driving it on the highway for a couple hours, then getting into stop and go traffic at long traffic lights, etc. Finally, about mid-summer it started to occur after about 20 minutes of driving in any condition. When the car ran like this for some time (usually more than 10 to 20 minutes, the check engine light would come on. Being an ODB 1 car, the local parts places couldn't do a reading for me.
After living with this the better part of the summer, I examined the plugs after a two hour trip at highway speeds with the car running roughly with low power and found cylinder #1's plug was tan, wet and glossy looking while the other three plugs looked normal. That, combined with other people's experience made me think the "running on three cylinders" description was more accurate than I had even suspected. With the car being 26 years old, the ignition coil or Ignition Control Module seemed to be the culprit, thinking that a micro fracture may have occurred that expanded when heated up.
Replaced the plugs, wires, ignition coil unit and the ICM with no useful effect: the problem still occurred after about 15 minutes of driving in the 100 degree heat today and the engine light came on. But the problem went away (and the light went out) after another 5 minutes then the problem came back. This repeated with another 5 minutes of driving. The car was parked for about 20 minutes, and the problem came back as soon as the car was started. Returning home, a bulb from a 6 volt flashlight was connected between pins 1 and 12 on the diagnostic connector to see what the code might be (since the engine light had stayed on), but the flashlight bulb did not light up even once.
What do I look at next?
