No Spark
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No Spark
I have a 1980 F100 with a V8. I just replaced the engine and I am not getting any spark. I have replaced the ignition coil module, the distributor, rotor, cap and wires and the coil is relatively new. I have performed all of the checks on each of the above and everything passes. I have power to the coil and the ignition control module. The truck ran before I removed the engine, so I am fairly certain all of the wires are correct. After reading multiple post, I am not sure if both sides of the coil should have power with the ignition switch in the run position. From what I have read, the red wire from the ICM plugs into a white wire and the white wire plugs into a red wire. Any suggestions would be appreciated.
Thanks, Mitchell
Thanks, Mitchell
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Joined: Mar 2008
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From: Washington
I have a 1980 F100 with a V8. I just replaced the engine and I am not getting any spark. I have replaced the ignition coil module, the distributor, rotor, cap and wires and the coil is relatively new. I have performed all of the checks on each of the above and everything passes. I have power to the coil and the ignition control module. The truck ran before I removed the engine, so I am fairly certain all of the wires are correct. After reading multiple post, I am not sure if both sides of the coil should have power with the ignition switch in the run position. From what I have read, the red wire from the ICM plugs into a white wire and the white wire plugs into a red wire. Any suggestions would be appreciated.
Thanks, Mitchell
Thanks, Mitchell
Look for these voltage readings. Assuming your battery is fully charged.
Key ON, engine not running
Coil positive around 8 volts, give or take a little.
Coil negative about ~1.5 volts
With the key left ON, the coil will get warm to the touch, which confirms current flow and a working primary ignition circuit.
Have you done the "flashing light test" on the coil negative while trying to start it?
Let me know what you find.
Jim
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From: Washington
The sole ground for the ignition system is in the distributor. There is a ground screw / clamp where the 3 wires change to 2 wires. Its a black wire.
Jim
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I discovered the ground on the new ICM was not making contact with the plug from the distributor. I switched the new ICM for the old one. The voltage at the coil drop from 12V to 7. The voltage also dropped to 1. 5 on the negative side. Still no spark. I guess I will purchase a new coil and have the wiring harness repaired with a new connector.
Mitchell
Mitchell
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Cargo Master
Joined: Mar 2008
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From: Washington
I discovered the ground on the new ICM was not making contact with the plug from the distributor. I switched the new ICM for the old one. The voltage at the coil drop from 12V to 7. The voltage also dropped to 1. 5 on the negative side. Still no spark. I guess I will purchase a new coil and have the wiring harness repaired with a new connector.
Mitchell
Mitchell
The coil negative voltage should change while cranking it over. From 12 v to 1.5 volts. This will cause a 12 volt test light to flash.
The other 2 wires in the distributor plug provide the needed AC signal which is goes to the DS2 IGN module causing the test light to flash. The AC signal is small and weak, thus any poor connection at this distributor plug will cause a no spark condition.
Jim
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Thanks for the info. Before I purchase a coil I will ensure all of the connections are working and replace as needed. I guess I have misread some of the information. With the key in the on position there should be 12 v on both the positive and the negative side of the coil, not 1.5 v on the negative and 6-8 v on the positive. The lower values are when cranking the engine.
I will post my results Friday.
I will post my results Friday.
Cargo Master
Joined: Mar 2008
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From: Washington
Thanks for the info. Before I purchase a coil I will ensure all of the connections are working and replace as needed. I guess I have misread some of the information. With the key in the on position there should be 12 v on both the positive and the negative side of the coil, not 1.5 v on the negative and 6-8 v on the positive. The lower values are when cranking the engine.
I will post my results Friday.
I will post my results Friday.
On my truck I have a GM 4 pin ignition module, current does not flow with the key ON, it must be cranking. So Ford and Chevy did it differently.
Good luck, Jim
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I would add ... another quick test: After verifying you have voltage to the coil positive terminal with Key On and while cranking.
Put a spark plug in the ignition coil wire and lay it on a good engine ground (you can use a jumper wire from spark plug base to ground if needed), then turn the key on and with a jumper wire touch coil neg to engine ground with quick touches (touch, remove, touch, remove, etc.) the plug should fire every time you ground and unground the coil neg terminal. If you get spark with this test then the coil is good. If no spark, replace coil.
Next crank on the motor and see if the plug fires quickly. If you do get a spark now, the distributor cap, rotor and plug wires are suspect. If you do not get a spark, then the pickup in the distributor is probably bad (or DS2 module).
Check the pickup in the distributor with an ohmmeter. The reluctor (pickup) coil in the distributor should have low resistance less than 10 ohms (across the purple and orange wires) .
Put a spark plug in the ignition coil wire and lay it on a good engine ground (you can use a jumper wire from spark plug base to ground if needed), then turn the key on and with a jumper wire touch coil neg to engine ground with quick touches (touch, remove, touch, remove, etc.) the plug should fire every time you ground and unground the coil neg terminal. If you get spark with this test then the coil is good. If no spark, replace coil.
Next crank on the motor and see if the plug fires quickly. If you do get a spark now, the distributor cap, rotor and plug wires are suspect. If you do not get a spark, then the pickup in the distributor is probably bad (or DS2 module).
Check the pickup in the distributor with an ohmmeter. The reluctor (pickup) coil in the distributor should have low resistance less than 10 ohms (across the purple and orange wires) .
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No luck today. Did not have a lot of time. I checked all of the to ensure everything had power. Then verified all of the wires were good. Maybe one of the connectors is not making good contact when plugged in.
I have a question regarding the black wire on the ignition control module. With the key in the on position and the connector not connected to the distributor, I measure 12 V. This is the wire that connects to the distributor ground. Should this have voltage?
I plan to fabricate a new wire harness Saturday, if all goes well,
Thanks,
Mitchell
I have a question regarding the black wire on the ignition control module. With the key in the on position and the connector not connected to the distributor, I measure 12 V. This is the wire that connects to the distributor ground. Should this have voltage?
I plan to fabricate a new wire harness Saturday, if all goes well,
Thanks,
Mitchell
Cargo Master
Joined: Mar 2008
Posts: 2,573
Likes: 207
From: Washington
No luck today. Did not have a lot of time. I checked all of the to ensure everything had power. Then verified all of the wires were good. Maybe one of the connectors is not making good contact when plugged in.
I have a question regarding the black wire on the ignition control module. With the key in the on position and the connector not connected to the distributor, I measure 12 V. This is the wire that connects to the distributor ground. Should this have voltage?
I plan to fabricate a new wire harness Saturday, if all goes well,
Thanks,
Mitchell
I have a question regarding the black wire on the ignition control module. With the key in the on position and the connector not connected to the distributor, I measure 12 V. This is the wire that connects to the distributor ground. Should this have voltage?
I plan to fabricate a new wire harness Saturday, if all goes well,
Thanks,
Mitchell
Back in post #7 when you measured 7 volts at the coil positive, that one voltage measurement proved the following.
Good power source and ground to the DS2 IGN module.
A good source of power for the coil and good ground for the coil.
A current flow of 4.5 amps (normal) for the primary ignition circuit.
Proper operation of the resistor wire.
Did you do the tests in post #11, countrybumkin's ideas are very good.
I personally have found the resistance to be around 600 ohms.... "Check the pickup in the distributor with an ohmmeter. The reluctor (pickup) coil in the distributor should have low resistance less than 10 ohms (across the purple and orange wires) ."
I would check this first at the Distributor plug then again at the 4 wire DS2 plug.
Jim
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Jim, I did perform the tests recommended by CountryBumpkin. I used a spark tester not a spark plug. when I used the spark tester I did get a spark. Not very bright. I did not get a spark when I used a spark plug. I performed the same test with a coil from another car with the same results. I have tested the distributor, I just do not remember the readings.
I had purchased a new coil and module. I do remember the readings for the pickup being the same for both distributors. Also all of the readings for the module are the same.
I also connected the good coil to the system, still no spark. I will probably purchase a new coil today, or order one if there is no one in stock.
i appreciate all of the help. It has me stumped. Everything was working fine before I switched engines. I keep thinking I forgot a wire somewhere, but there are no more wires left to connect
Mitchell
I had purchased a new coil and module. I do remember the readings for the pickup being the same for both distributors. Also all of the readings for the module are the same.
I also connected the good coil to the system, still no spark. I will probably purchase a new coil today, or order one if there is no one in stock.
i appreciate all of the help. It has me stumped. Everything was working fine before I switched engines. I keep thinking I forgot a wire somewhere, but there are no more wires left to connect
Mitchell
Cargo Master
Joined: Mar 2008
Posts: 2,573
Likes: 207
From: Washington
Jim, I did perform the tests recommended by CountryBumpkin. I used a spark tester not a spark plug. when I used the spark tester I did get a spark. Not very bright. I did not get a spark when I used a spark plug. I performed the same test with a coil from another car with the same results. I have tested the distributor, I just do not remember the readings.
I had purchased a new coil and module. I do remember the readings for the pickup being the same for both distributors. Also all of the readings for the module are the same.
I also connected the good coil to the system, still no spark. I will probably purchase a new coil today, or order one if there is no one in stock.
i appreciate all of the help. It has me stumped. Everything was working fine before I switched engines. I keep thinking I forgot a wire somewhere, but there are no more wires left to connect
Mitchell
I had purchased a new coil and module. I do remember the readings for the pickup being the same for both distributors. Also all of the readings for the module are the same.
I also connected the good coil to the system, still no spark. I will probably purchase a new coil today, or order one if there is no one in stock.
i appreciate all of the help. It has me stumped. Everything was working fine before I switched engines. I keep thinking I forgot a wire somewhere, but there are no more wires left to connect
Mitchell
When you used the spark tester did you plug it directly into the coil? Did you tried a different coil and coil wire off the other car or have you been always using the same coil wire?
The fact that you are seeing a weak spark means the pickup in the distributor is working.
The no spark is now really a weak spark, unable to jump the .045 gap. If the gap was .015 it might jump the plug gap.
Jim