paragraph please.
I can't start my '81 CIS pickup.
I read to check the coil, you should ground a test light and touch on the positive terminal (15) to see if you have voltage, and that it should be 12v or about the same as your battery with the ignition switch on.
That is correct with the ignition switch on there should be B+ at the coil pins 15 and pin 4>
Do you have points/condenser or do you have electronic ignition?
I had 13 volts at my battery. When I checked the #15 terminal on the coil with the test light, it lit up red. when I touched the negative terminal on the coil (#1), it also lit up red. If I check my test light at the battery, it will either light up red or green when I touch both terminals, depending on which side of the battery I make contact with.
You have a Polarized noid light. Green good Red Bad.
So much for the test light--does anyone understand why there would be two colors on a basic test light? Does red indicate a reverse connection or some problem?
yep
Now to the multi-meter voltage test at the battery and coil. I had about 13v at the battery before testing the coil. When I tested the coil with the ignition on, I had about 14v on both sides--they tested the same, just like the test light.
Coils are but a step up transformer that is you have a itty bitty run of wire and a big run of wire.... It is the diz that causes the field in the coil to collapse and come shooting out at 20KV on the larger side. So statically it isn't that far off to see the same voltage on different ends. Also they do go bad and short internally had to diagnose as well.
The test light is old and I don't have the instructions with it. I didn't think I should have voltage on the negative, #1 side of the coil with the ignition on. I also was surprised to see higher voltage at the coil.
Prior to this I had a voltage regulator malfunction at the alternator and was charging about 18 volts. I haven't been able to start the truck since and don't know if there is a problem with the ignition coil, the ignition control module, or what.
I have installed a new alternator and battery prior to testing. Could the ignition switch be faulty?
I also noticed one of the spade connectors on the fuel pump relay seems to have overheated. I believe it's either terminal 30 or 87---one of the two you bridge to run the fuel pump by bypassing the relay. What might cause this connection to overheat?
Fuel pump relays go bad, but they get their run signal from the coil and ICM.
So lets get basic.
Set the car in Static time. so all the marks line up, and we all know where we are.
Verify that the Diz is in the middle of the HASH.
Verify that all your plug wires are correctly. (www:cabby-info.com has good pictures)
If you have point and condenser, replace the condenser.
If you have Electronic ignition, Carefully remove the rubber boot off the plug that goes in to the diz.
Loosen the clamping bolt on the DIZ.
Insert your Positive probe of a DVOM in to the Green/white wire
Ignition on and in the Run not START mode.
If you rotate your Diz your meter should go from 0-11V and when it reaches 11, the fuel pumps turn on.
If you are not getting 11V swing, then the ICM powers the DIZ (there is a go-no-go test in the bentley for them).
For the digifant they are like 12 dollars. If your ICM check out then you could have a bad hall generator in the diz.
Ok. Ignition switches do go bad, they are easy to diagnose.
Car in Neutral.
Parking brake full on.
Turn the ignition switch to run
Jumper 12V positive to the Starter solenoid if the car starts and runs then your switch is probably good, if the starter doesn’t engage in the Key to start then it is bad.
But the Caveat is that the Switches Run side is enabled on both the Starter engage and the run side…
Only the load reduction relay cuts in to remove power from the headlights.
I would replace the Fuel pump relay get one that looks internally like yours.
see cabby-info.com she has the part numbers and what to look out for internally.
I tend to think that the 18V took out the ICM and or the Hall sender in the Diz…. but lets do some further testing first.
Oh since we set the car in time, and moved the diz be sure you reset the diz so the rotor is in the middle of the hash, then clamp it down. before you try to start the car.
Very few parts on EFI , the hall generator in the diz, the ICM and the Coil.
Your Test light tells you if you are seeing a Positive voltage to ground or not. you have to reverse the leads to see which is the positive light and which is the ground... Usually the wire with the clip is the ground and the pointy end of the probe is the positive.
It dosen't matter as long as you know which is which when you jumper it across the battery one way a light comes on, reverse it and the other comes on...
I can't start my '81 CIS pickup.
I read to check the coil, you should ground a test light and touch on the positive terminal (15) to see if you have voltage, and that it should be 12v or about the same as your battery with the ignition switch on.
That is correct with the ignition switch on there should be B+ at the coil pins 15 and pin 4>
Do you have points/condenser or do you have electronic ignition?
I had 13 volts at my battery. When I checked the #15 terminal on the coil with the test light, it lit up red. when I touched the negative terminal on the coil (#1), it also lit up red. If I check my test light at the battery, it will either light up red or green when I touch both terminals, depending on which side of the battery I make contact with.
You have a Polarized noid light. Green good Red Bad.
So much for the test light--does anyone understand why there would be two colors on a basic test light? Does red indicate a reverse connection or some problem?
yep
Now to the multi-meter voltage test at the battery and coil. I had about 13v at the battery before testing the coil. When I tested the coil with the ignition on, I had about 14v on both sides--they tested the same, just like the test light.
Coils are but a step up transformer that is you have a itty bitty run of wire and a big run of wire.... It is the diz that causes the field in the coil to collapse and come shooting out at 20KV on the larger side. So statically it isn't that far off to see the same voltage on different ends. Also they do go bad and short internally had to diagnose as well.
The test light is old and I don't have the instructions with it. I didn't think I should have voltage on the negative, #1 side of the coil with the ignition on. I also was surprised to see higher voltage at the coil.
Prior to this I had a voltage regulator malfunction at the alternator and was charging about 18 volts. I haven't been able to start the truck since and don't know if there is a problem with the ignition coil, the ignition control module, or what.
I have installed a new alternator and battery prior to testing. Could the ignition switch be faulty?
I also noticed one of the spade connectors on the fuel pump relay seems to have overheated. I believe it's either terminal 30 or 87---one of the two you bridge to run the fuel pump by bypassing the relay. What might cause this connection to overheat?
Fuel pump relays go bad, but they get their run signal from the coil and ICM.
So lets get basic.
Set the car in Static time. so all the marks line up, and we all know where we are.
Verify that the Diz is in the middle of the HASH.
Verify that all your plug wires are correctly. (www:cabby-info.com has good pictures)
If you have point and condenser, replace the condenser.
If you have Electronic ignition, Carefully remove the rubber boot off the plug that goes in to the diz.
Loosen the clamping bolt on the DIZ.
Insert your Positive probe of a DVOM in to the Green/white wire
Ignition on and in the Run not START mode.
If you rotate your Diz your meter should go from 0-11V and when it reaches 11, the fuel pumps turn on.
If you are not getting 11V swing, then the ICM powers the DIZ (there is a go-no-go test in the bentley for them).
For the digifant they are like 12 dollars. If your ICM check out then you could have a bad hall generator in the diz.
Ok. Ignition switches do go bad, they are easy to diagnose.
Car in Neutral.
Parking brake full on.
Turn the ignition switch to run
Jumper 12V positive to the Starter solenoid if the car starts and runs then your switch is probably good, if the starter doesn’t engage in the Key to start then it is bad.
But the Caveat is that the Switches Run side is enabled on both the Starter engage and the run side…
Only the load reduction relay cuts in to remove power from the headlights.
I would replace the Fuel pump relay get one that looks internally like yours.
see cabby-info.com she has the part numbers and what to look out for internally.
I tend to think that the 18V took out the ICM and or the Hall sender in the Diz…. but lets do some further testing first.
Oh since we set the car in time, and moved the diz be sure you reset the diz so the rotor is in the middle of the hash, then clamp it down. before you try to start the car.
Very few parts on EFI , the hall generator in the diz, the ICM and the Coil.
Your Test light tells you if you are seeing a Positive voltage to ground or not. you have to reverse the leads to see which is the positive light and which is the ground... Usually the wire with the clip is the ground and the pointy end of the probe is the positive.
It dosen't matter as long as you know which is which when you jumper it across the battery one way a light comes on, reverse it and the other comes on...
