Front Defrost making car surge

[vonollie]

When I turn on any part of the front defrost (defrost/floor or just defrost) the car goes through engine surges where it makes me feel like I'm losing power. I think it also does it when I turn on the a/c as well. Any help here on what to look for? I saw something about drilling out a ribbon on the panel to stop this, but don't know if a/c would still work if I get it fixed later. Can I just unplug wires going to a/c compressor to stop this as well? Really sucks running defrost and having car surge like it does.

[EZFrank]

our car is doin the same thing when we put the heater or ac on car starts to idle very high on its own can somebody explain why it does this. Thanks

[palindromelol]

I will attempt to try for the low idle case. There is a Technical service bulletin issued by Dodge on this (see next post). I'll paraphrase since it was rather lengthly. Any electrical load of consequence requires generation of electricity to replenish energy extracted from the battery. This all happens at the speed of electrons. Headlights, A/C, Blowers, radiator fan. These are the main electrical loads. (Starter not included)

The engine control attempts to maintain idle at 700 RPM say. When a large load is dropped on the electrical system, the generator gets harder to spin and the engine slows. In response to the slowing engine, the computer allows more fuel and air to be admitted into the intake to the engine. Theoretically, the engine could recover very quickly and return idle to 700 rpm even under heavy electrical load. The trouble comes when the load is turned off. What would happen? You guessed correct. The engine would race up and overshoot. The engineers who wrote the program to control the engine idle decided that STABILITY was more important the the ERROR in the idle speed. They elected to instruct the engine to be at low idle under load deliberately. This was very intentional. The engine isn't loosing power. (vonollie) It is designed to slow a bit underload so that it does not over run when the loads are taken of the engine.

For you controls system weiners out there. The Term is PID control. (Proportional, Integral, and Derivative)

P is related to the gain or umph behind the engine (Small engines make this small)
I is the ERROR correction (set low for neons)
D is stability (engine hunting speed) very stablein neons

So normal is the low idle under load. 8 cylinders don't have it so much because of the P or Gain.

vonollie take out the A/C clutch relay from the PDC behind the battery. It will give you and engine service code but the cycling will stop.

[palindromelol]

vonollie... check out this link...
http://www.neons.org/neontsb/TSB/18/182097.htm