Heres one for you guys

[93GASE3300]

Allright here is the deal I have a 1993 Grand Am SE with the 3.3 V6. I posted once before about my engine surging. I just realized more conditions that happen during it. The car will idle erradically normally after I stop at a light after the car is at operating temp. I just realized that the surging doesnt happen until the cooling fan kicks on. If I shut the car down and restart the surging stops and then starts again when the cooling fan starts again. When the fan shuts down the car continues to surge for about 30 seconds and then smooths out again. Now heres the question. Is the cooling fan creating such a significant draw on my electrical system that it is making my engine surge or is it something else that is related to this issue? I would really like your guys opinion and suggestions on this problem. Any help you can give me will be helpful.

[Granny-Am]

The control module provides a 5 volt reference signal to the sensor through a resistor in the module and measures the voltage. The voltage will be high when the engine is cold and low when the engine is hot. By measuring the voltage, the control module knows the engine coolant temperature. The engine coolant temperature affects most other systems controlled by the module.

This may be your reason for the voltage fluctuation.

:angel2:

[93GASE3300]

Im not sure if that is what may cause the voltage fluctuation or if there even is one but I will check and post my results. Thanks for your help I appreciate it.

[4kQuad]

vacumm problems cause that, Read about a person with a Cold Temp. censor they had left unhooked. Caused some real problems untill it was rehooked.

The leak is after the butterfly in the throttle body. Check hoses that connect to it after there.

[93GASE3300]

actually what I am thinking is that some of the other problems I am having may relate to this problem. I have a code 26 which is a quad driver module circuit problem. I looked at the schematic and noticed that the cooling fan relay is in the circuit. I will look into it a little more but this could be a big pain in the butt.

[Granny-Am]

VOLTAGE DROP
Fig. 1: This voltage drop test revealed high resistance (low voltage) in the circuit



When current flows through a load, the voltage beyond the load drops. This voltage drop is due to the resistance created by the load and also by small resistances created by corrosion at the connectors and damaged insulation on the wires. The maximum allowable voltage drop under load is critical, especially if there is more than one load in the circuit, since all voltage drops are cumulative.

Set the voltmeter selector switch to the 20 volt position.
Connect the multimeter negative lead to a good ground.
Operate the circuit and check the voltage prior to the first component (load).
There should be little or no voltage drop in the circuit prior to the first component. If a voltage drop exists, the wire or connectors in the circuit are suspect.
While operating the first component in the circuit, probe the ground side of the component with the positive meter lead and observe the voltage readings. A small voltage drop should be noticed. This voltage drop is caused by the resistance of the component.
Repeat the test for each component (load) down the circuit.
If a large voltage drop is noticed, the preceding component, wire or connector is suspect.

RESISTANCE
Fig. 1: Checking the resistance of a coolant temperature sensor with an ohmmeter. Reading is 1.04 kilohms



Fig. 2: Spark plug wires can be checked for excessive resistance using an ohmmeter



WARNING
Never use an ohmmeter with power applied to the circuit. The ohmmeter is designed to operate on its own power supply. The normal 12 volt electrical system voltage could damage the meter!

Isolate the circuit from the vehicle's power source.
Ensure that the ignition key is OFF when disconnecting any components or the battery.
Where necessary, also isolate at least one side of the circuit to be checked, in order to avoid reading parallel resistances. Parallel circuit resistances will always give a lower reading than the actual resistance of either of the branches.
Connect the meter leads to both sides of the circuit (wire or component) and read the actual measured ohms on the meter scale. Make sure the selector switch is set to the proper ohm scale for the circuit being tested, to avoid misreading the ohmmeter test value.

[93GASE3300]

thank you for the info. I have doing this stuff for about a year now but it is a great help to sort of get a refresher course on things I dont use all the time. I will check the voltage drops and resistances. The real issue is getting to all those damn wires, LOL. Thanks again.