Cougar

Here is what the code definition is: Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor) . You do need check the wiring to the sensor for a connection problem and probably replace the sensor. This is a dealer only item. They will know the right one you need from the year of the car. When installing a new one, do not over torque it.

Citrushark, Have you measured the resistance of the injector yet?

Oddcomp, I don't have a manual for an '87 model but my '88 model shows the termination for the SPFI injector to be internal to the ECU as JIK mentioned and I assume that the '87 is the same. I know my '88 MPFI had external resistors. The wire colors are Red/White and Red/Black as JIK mentioned.

You called it Frag. Another successful trouble shooting job done. Thanks for the help. If this problem helps Tim understand more about electrical trouble shooting with his meter then all the better.

Well I guess that will fix the code problem. I guess some of the newer cars have two sensors at least. Keep up the practice on the meter functions. If you have any questions let us know.

IAC is for Idle Air Control, Tim. So the connector was off as Frag suspected.

The body of the coil needs to have a good connection to ground. It is usually stapped down in a holder of some sort.

Ok. Thanks again for the info John.

I agree Frag.

You are correct Frag. I've been tring to find out what is going on with that. I thought Tim just got a '97 OBW which I thought had just one sensor with two leads, but he hasn't stated what model this is yet.

I think you will enjoy it even more when you start finding problems using the meter and really understanding the functions. It sounds like you are measuring resistance while the sensor is hooked up and the car is running, if so, remember you need to have power removed from the circuit while measuring resistance. You can measure the voltage though. Does the sensor only have one lead? If so, then you need to use ground as the reference and the meter's common lead (the black, or minus lead) would tie to ground.

Thanks for the input Emily. You folks should know.

Your welcome for the help Tim. Learning to use an analog meter is a little more difficult than a digital one but not hard. You need to be more careful when making measurements because the meter movement can be damaged if the scale or the function is set wrong while taking a measurment. All meters need to have power removed from the circuit when measuring resistance. This is because the meter sends out a current to flow through the device under test and measures that current in ohms on the meter face. Most analog meters have a zero adjustment along with a multiplier scale (R x1, R x10, R x1000, R x10,000). The multiplier scale is needed so that when measuring either very low or very large resistances you will be able read them on the scale. If you measure a resistor and the needle moves to 4.5 on the scale you then need to check what multiplier is selected. Let's say it is at R x 100. Then you need to multiply the reading by 100, 100 x 4.5= 4,500 ohms or 4.5k ohms (k stands for kilo or 1000). If the multiplier was set at R x1 then it would be just 4.5 ohms. Before measuring anything though you need to set the zero point on the scale. You do this by set the resistance multiplier you want to use and then short the meter probes together. Then set the needle to read "0" using the zero adjustment. The meter is ready for use then. This is needed for changes in the battery voltage in the meter. Always check the zero when changing scales. To measure current you need to know the polarity of the voltage and place the meter leads in series, with proper polarity, in the circuit you want to measure. You should always start using a large scale so you don't peg the meter and damage it. It is good practice to first remove power to the circuit, place the meter in the circuit you want to measure, then apply power. You need to watch what scale you are set to in order to read the correct current. I guess you know how to read voltages already so I won't mention anything on that unless there is a question. The nice thing about digital meters is you don't have to zero it or watch the polarity. It takes care of things for you and they are usually protected well when the meter is set wrong while checking things. You don't have to worry about what scale you are on also. You should get one when you can. They are not that expensive and really good to have on hand. One thing you can do Tim is disconnect the sensor and see if you temperature gauge changes. I'm pretty sure it will. I think there may be another sensor for the ECU and fans. Have you noticed one?

I need to go get dinner. I will check back in about an hour.

Analogs are a little more harder to use on resistance than digital and you need to be sure that there is no voltage to the circuit when you measure resistance. It can damage the meter otherwise. Do you have an instruction manual with the meter? If so, you should read it. Another thing you can do is measure the voltage of the sensor while things warm up. Also it seems to me that if the sensor has only one lead then that would be the one for the gauge and there may be another for the ECU that has two leads to it.

This is your new '97 model correct? What kind of meter do you have? Refer to my last post.

Using a meter is pretty easy Tim. Before long you will wonder how you got by without it. Is you meter a digital or analog (with a meter movement)? Analog meters usually require a calibration of the meter before testing.

Tim, I did see one note about resistance in my manual. It stated that measuring one of the pins (pin 2) of sensor with the ignition off should not be less than 5 ohms to ground. It looks like my idea of being isolated to ground is wrong. The sensor is bad if the reading is less.

The best thing to do Tim is measure the resistance of the disconnected sensor and see what it is. If the resistance is real low the sensor may be bad. There may also be a wiring problem to the sensor causing a low voltage to it. You could try substituting the sensor with a resistor that would be the proper resistance of a warm engine. If the problem is cleared then the sensor needs to be replaced. I'm sorry I can't give you any specs on the resistance. My manual doesn't give any. Also check the resistance of the sensor leads to ground. They should normally be isolated from ground I think. As a science project you could measure the resistance of the sensor as the engine warms up. Record the cold reading and then record the warm reading. You should see a pretty good change in resistance between the two readings if the sensor is good. Remove the sensor connection before measuring the reistance of the sensor.

Place the test light on the minus side of the coil and clip lead to ground. Then try cranking the engine. If the light is on but doesn't pulse on and off for the ignition pluses then the pick up in the distributor is bad. If you have low or no light then the coil is bad. Also make sure the ground to the coil is good.

No, they don't need to be connected.

To John in KY: Thanks for the resistance specs of the injector. Does the manual show the ground connection for the injector going to an external resistor or ground connection, or is it just terminated inside the ECU?

That is normal. I think that means you have a manual transmission.

It means that the power to the injector is probably ok but to really prove that you should check the voltage using a analog meter with the common lead of the meter tied to a good ground and the connector tied to the injector. Then monitor the voltage to each side of the injector while cranking the engine. If you still have 12 volts with no pulsing on both leads then the grounding side (ECU) end of the circuit is not getting to ground somehow. There may be a seperate resistor to gound for that injector that is bad or not connected correctly. You should verify the ground side resistance, for that injector, out of the ECU. If the resistance is ok, then there is either a bad connection between the ECU and the injector, or the ECU control for that circuit is bad. I doubt the ECU is bad though. You can also check the ECU sides of the circuit by placing the meter on DC volts and place the common lead to a good ground. Then find the proper contacts on the ECU for the input and return side for that injector. If the voltage fluctuates while starting the engine on both connections then the ECU is ok and the connection to the injector is bad.

After thinking about the resistances again it may be that it is about 3-4 ohms of resistance. I'm pretty sure there is a connector to the injector but I haven't messed with one yet so I can't say for sure. You could try probing through the wires to it to check the resistance with the engine off.