Problem with coil
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Problem with coil
I just got done installing a rebuilt 351W into my 92 F150 and I think I have a problem with my coil connections. I tried to start the truck and I don't think I am getting spark. I connected a timing light to the coil wire that goes to the distributor and the light never went on. I thought the light should go on each time the light detects a signal in the coil wire.
When I tested the connections that go into the coil, both lead to the same place at the TFI module that is mounted on the firewall (pin #4). Both also seem to go to the plug that connects to the distributor. I don't think that is right
. I have no idea where but those wires must be crossed somewhere.
So if I test each wire (I have a red wire with green stripe and a yellow wire with some color stripe), where should each go?
Also, when the coil is mounted, which of those two wires goes to which side of the coil?
Thanks.
When I tested the connections that go into the coil, both lead to the same place at the TFI module that is mounted on the firewall (pin #4). Both also seem to go to the plug that connects to the distributor. I don't think that is right
. I have no idea where but those wires must be crossed somewhere.So if I test each wire (I have a red wire with green stripe and a yellow wire with some color stripe), where should each go?
Also, when the coil is mounted, which of those two wires goes to which side of the coil?
Thanks.
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From: Calverton
I posted this in another thread you were in for you...just in case you don't read that one, here you go
The biggest factor with the distributor is having free adjustment movement on both sides of number one. Try this, wrench the motor clockwise, stop at TDC. Install the distributor so as looking down in the distributor at the pickup, the rotor is on the right side of the pickup, in other words before and soon to pass...that's assuming the the rotor travels counter clockwise during operation, I did not look that up to see for sure, for the 351. It may take you a couple of times to find the right gear tooth position, that allows you to have the rotor at #1 and at pre pickup alignment. look here too Ford Fuel Injection » Setting the timing
The biggest factor with the distributor is having free adjustment movement on both sides of number one. Try this, wrench the motor clockwise, stop at TDC. Install the distributor so as looking down in the distributor at the pickup, the rotor is on the right side of the pickup, in other words before and soon to pass...that's assuming the the rotor travels counter clockwise during operation, I did not look that up to see for sure, for the 351. It may take you a couple of times to find the right gear tooth position, that allows you to have the rotor at #1 and at pre pickup alignment. look here too Ford Fuel Injection » Setting the timing
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I did some more testing and I think I am not getting the signal to the coil to fire. Or does it stay on all the time and supply power to the distributor when the points connect? Anyway, I left the coil-to-distributor wire connected to the coil and I removed the other end from the distributor and grounded that side. I clamped the timing light wire to it and then tried starting the truck, I didn't see the timing light fire. Since it's just connected to the coil I assume the coil isn't generating output for some reason. I tested the coil according to my Haynes manual and it tested near the lower limits. The coil I am using is new.
I also need to replace the aluminum shielding on the wires near the PCM. Last year I upgraded to MASS Air and never put that back. I don't think that is the cause of my problem though.
What I am now curious about is if I have the 22K OHM resistor that goes to pin 4 on the PCM. Anyone know where that would be or how to test if it is there?
I also need to replace the aluminum shielding on the wires near the PCM. Last year I upgraded to MASS Air and never put that back. I don't think that is the cause of my problem though.
What I am now curious about is if I have the 22K OHM resistor that goes to pin 4 on the PCM. Anyone know where that would be or how to test if it is there?
Fleet Owner
Joined: Oct 2005
Posts: 20,783
Likes: 1,748
From: Kentucky
I did some more testing and I think I am not getting the signal to the coil to fire. Or does it stay on all the time and supply power to the distributor when the points connect? Anyway, I left the coil-to-distributor wire connected to the coil and I removed the other end from the distributor and grounded that side. I clamped the timing light wire to it and then tried starting the truck, I didn't see the timing light fire. Since it's just connected to the coil I assume the coil isn't generating output for some reason. I tested the coil according to my Haynes manual and it tested near the lower limits. The coil I am using is new.
I also need to replace the aluminum shielding on the wires near the PCM. Last year I upgraded to MASS Air and never put that back. I don't think that is the cause of my problem though.
What I am now curious about is if I have the 22K OHM resistor that goes to pin 4 on the PCM. Anyone know where that would be or how to test if it is there?
I also need to replace the aluminum shielding on the wires near the PCM. Last year I upgraded to MASS Air and never put that back. I don't think that is the cause of my problem though.
What I am now curious about is if I have the 22K OHM resistor that goes to pin 4 on the PCM. Anyone know where that would be or how to test if it is there?
As far as the coil itself: you said "Or does it stay on all the time and supply power to the distributor when the points connect?"
There are no points, you have an electronic ignition. The positive side of the coil always has +12 VDC when the key is in the Start or Run position. It's the PIP, aka Stator, inside the distributor that starts the process to tell the PCM, then ICM to momentarily ground the coil.
Cut from my Ford service Manual:
How The Circuit Works
The Distributor contains no centrifugal or vacuum advance mechanisms. All spark advance/retard is accomplished electronically by the Electronic Engine Control (EEC) Module.
During engine cranking (and after the engine starts), a Hall Effect Switch inside the Distributor assembly sends a variable voltage signal to the Thick Film Integrated (TFI) Ignition Module, which is mounted on the left fender wall.
The TFI Ignition Module passes this Profile Ignition Pickup (PIP) signal to the Electronic Engine Control (EEC) Module, which uses it to determine crankshaft position and engine speed. Using the signal and information provided by other engine control sensors, the EEC Module determines the appropriate ignition timing. The EEC Module then sends a Spark Output (SPOUT) timing signal back to the TFI Ignition Module.
The TFI Ignition Module turns the Ignition Coil primary circuit on and off, according to the SPOUT signal from the EEC Module. Each interruption of the Ignition Coil primary circuit causes the Ignition Coil secondary circuit to produce an open circuit high voltage pulse of up to 40,000 volts. These high voltage pulses are routed to the Distributor, which sends them to the spark plugs.
The EEC Module monitors the TFI Ignition Module's control of the Ignition Coil through the Ignition Diagnostic Monitor (IDM) circuit.
If the TFI Ignition Module does not receive a SPOUT signal from the EEC Module, the Ignition Module will set timing at a fixed value.
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Some good info in this thread: '94 code 212 mystery IDM Resistor ??? - FSB Forums
As far as the coil itself: you said "Or does it stay on all the time and supply power to the distributor when the points connect?"
There are no points, you have an electronic ignition. The positive side of the coil always has +12 VDC when the key is in the Start or Run position. It's the PIP, aka Stator, inside the distributor that starts the process to tell the PCM, then ICM to momentarily ground the coil.
Cut from my Ford service Manual:
How The Circuit Works
The Distributor contains no centrifugal or vacuum advance mechanisms. All spark advance/retard is accomplished electronically by the Electronic Engine Control (EEC) Module.
During engine cranking (and after the engine starts), a Hall Effect Switch inside the Distributor assembly sends a variable voltage signal to the Thick Film Integrated (TFI) Ignition Module, which is mounted on the left fender wall.
The TFI Ignition Module passes this Profile Ignition Pickup (PIP) signal to the Electronic Engine Control (EEC) Module, which uses it to determine crankshaft position and engine speed. Using the signal and information provided by other engine control sensors, the EEC Module determines the appropriate ignition timing. The EEC Module then sends a Spark Output (SPOUT) timing signal back to the TFI Ignition Module.
The TFI Ignition Module turns the Ignition Coil primary circuit on and off, according to the SPOUT signal from the EEC Module. Each interruption of the Ignition Coil primary circuit causes the Ignition Coil secondary circuit to produce an open circuit high voltage pulse of up to 40,000 volts. These high voltage pulses are routed to the Distributor, which sends them to the spark plugs.
The EEC Module monitors the TFI Ignition Module's control of the Ignition Coil through the Ignition Diagnostic Monitor (IDM) circuit.
If the TFI Ignition Module does not receive a SPOUT signal from the EEC Module, the Ignition Module will set timing at a fixed value.
As far as the coil itself: you said "Or does it stay on all the time and supply power to the distributor when the points connect?"
There are no points, you have an electronic ignition. The positive side of the coil always has +12 VDC when the key is in the Start or Run position. It's the PIP, aka Stator, inside the distributor that starts the process to tell the PCM, then ICM to momentarily ground the coil.
Cut from my Ford service Manual:
How The Circuit Works
The Distributor contains no centrifugal or vacuum advance mechanisms. All spark advance/retard is accomplished electronically by the Electronic Engine Control (EEC) Module.
During engine cranking (and after the engine starts), a Hall Effect Switch inside the Distributor assembly sends a variable voltage signal to the Thick Film Integrated (TFI) Ignition Module, which is mounted on the left fender wall.
The TFI Ignition Module passes this Profile Ignition Pickup (PIP) signal to the Electronic Engine Control (EEC) Module, which uses it to determine crankshaft position and engine speed. Using the signal and information provided by other engine control sensors, the EEC Module determines the appropriate ignition timing. The EEC Module then sends a Spark Output (SPOUT) timing signal back to the TFI Ignition Module.
The TFI Ignition Module turns the Ignition Coil primary circuit on and off, according to the SPOUT signal from the EEC Module. Each interruption of the Ignition Coil primary circuit causes the Ignition Coil secondary circuit to produce an open circuit high voltage pulse of up to 40,000 volts. These high voltage pulses are routed to the Distributor, which sends them to the spark plugs.
The EEC Module monitors the TFI Ignition Module's control of the Ignition Coil through the Ignition Diagnostic Monitor (IDM) circuit.
If the TFI Ignition Module does not receive a SPOUT signal from the EEC Module, the Ignition Module will set timing at a fixed value.
This info helped...a lot. Now that I understand how it works, I can test it and know what the results mean. By points I meant the contacts on the rotor and under the cap. I thought the coil worked by sending a pulse to the cap each time it was ready to fire a plug, obviously that isn't the case.
There is a 0.20" gap between the rotor and the center contact on the distributor cap. Aren't they supposed to touch? Doesn't the center contact in the middle of the cap ride on the metal part in the center of the rotor?
Last edited by RIKIL; Nov 4, 2011 at 06:39 PM. Reason: cuz
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Fleet Owner
Joined: Oct 2005
Posts: 20,783
Likes: 1,748
From: Kentucky
The bottom of the center contact on the distributor cap has a rubber center in it. That is what contact the top of the rotor. There is no metal to metal contact between the rotor and any of the distributor cap. High voltage jumps across the gap then travel down to the plug(s).
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I found out that I am getting a spark to the plugs. The timing light I have can't detect the signal through the 9mm wires I have. I had a friend come over and we put on a generic, less insulated wire and we got the light to flash.
We weren't able to check the timing then but at least it's progress.
We weren't able to check the timing then but at least it's progress.
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