Gray or Black Module?
Thread Starter
Member
Joined: Sep 2015
Posts: 61
Likes: 5
Gray or Black Module?
In chasing my no start issue, I am wondering how you can tell for sure which module, gray or black, your vehicle should have? It seems that it could have either, but what it the determining factor for a push start or non-push start module?
Thread Starter
Member
Joined: Sep 2015
Posts: 61
Likes: 5
Interesting as mine is old and gray and mounted on the fender. But this truck has had issues from day one and someone else may have replaced the module with an incorrect used one. Are you sure as they made both gray and black for distributor mounted modules? Seeing as Ford wisely made both gray and black for both fender and dist. mounts, there must be another way to tell which one the truck should use. I've tried a VIN decoder, but that does not go as far as the ignition module. Too bad Ford didn't use "born date" like a cool Budweiser....
Last edited by RPetty_43; Jan 17, 2016 at 12:09 PM.
Senior Member
Joined: Jun 2015
Posts: 2,918
Likes: 489
From: Oregon
Yeah then it should be black if it is on the fender. There might be exceptions. I'd at least pull it and then google the part number, if nothing else.
FWIW I replaced my motorcraft original with a standard motor products LX241 and it works great. Fender mounted.
FWIW I replaced my motorcraft original with a standard motor products LX241 and it works great. Fender mounted.
Senior Member
Joined: Dec 2014
Posts: 1,037
Likes: 141
From: South Dakota
There is another place on the internet with an extremely knowledgeable guy. He says 1994 and newer take the black module. He also says a lot of the parts books are wrong including some of Fords.
Trending Topics
Thread Starter
Member
Joined: Sep 2015
Posts: 61
Likes: 5
There is a difference as apparently the #4 pin goes to the PCM with the black one and to the dist. with the gray one. Sadly, both will work on the other system, just not correctly and may fail eventually. This seems to be a design criteria with Ford ignition systems. Looks like I will be tracing wires..... As follows:
Most technicians who deal with Ford driveability and no-start problems have become very familiar with the Thick Film Ignition (TFI) system. Ford started using the six-pin TFI module with the EEC-IV computer system in 1983, and for years it remained basically unchanged.
The early TFI system, which Ford calls the "Push Start" TFI system, uses a gray TFI module. Originally, the module was mounted on the distributor. In the late '80s Ford began to relocate it away from the distributor on some vehicles to provide better protection from the effects of engine heat, but system operation remained the same. It uses a Hall effect pickup (stator) in the distributor, which generates a battery voltage, 50% duty cycle square wave, called the PIP signal, to the EEC-U PCM and the TFI module. The PCM processes this signal and sends out another battery voltage, 50% duty cycle square wave, called the SPOUT signal, to the TFI module. As long as the TFI module is receiving a SPOUT signal, it will fire the coil at the rising edge of that signal (except during engine cranking, when SPOUT is ignored) and the vehicle will run with the amount of timing advance commanded by the computer. If the TFI module does not receive the SPOUT signal, it will fire the coil at the rising edge of the PIP signal, a nd the vehicle will run at base timing. This is true on all TFI systems.
Ignition dwell with the Push Start (gray module) system is controlled by the TFI module alone, and increases with engine rpm. The Ignition Diagnostic Monitor (IDM) signal on a Push Start TFI system comes from the coil negative circuit and is filtered through a 22k ohm resistor to pin #4 on the EEC-IV computer. The computer monitors this circuit to verify a coil firing for each PIP signal, and sets codes if it sees missing or erratic signals. Another feature that is unique to the Push Start TFI system is the start input on pin #4 of the module connector. This is wired into the starter relay trigger circuit, and signals the TFI module that the engine is cranking. When the module sees battery voltage on this circuit, the SPOUT signal is ignored.
In the early '90s, Ford began using a different TFI system on certain vehicles--the Computer Controlled Dwell (CCD) TFI system. The TFI module on CCD TFI is always black in color. There are a few major differences between the two systems. As the name implies, with the CCD system, the computer controls primary dwell. The CCD TFI module still ungrounds (fires) the coil at the rising edge of the SPOUT signal, but now the falling edge of the SPOUT signal (which had no meaning to the Push Start TFI module) is used by the CCD TFI module to ground the coil. The PIP signal remains the same 50% duty cycle square wave, but SPOUT signal duty cycle varies according to how much dwell is desired by the computer.
Another major difference between the two systems is the IDM circuit. Pin #4 on the CCD TFI module, which was the start circuit input on the Push Start TFI module, is now the IDM signal, sent directly from the TFI module to pin #4 on the EEC-IV computer. This signal is still a filtered (low voltage) version of the ignition primary waveform, but is filtered internally in the TFI module rather than through an external resistor. There isn't any start circuit input to the CCD TFI module; the module infers engine cranking from a low rpm input from the PIP signal.
Since these two TFI systems are so significantly different, yet so similar in appearance, parts application problems will inevitably occur. A gray Push Start TFI module will plug right into a CCD system, and vice versa. To make matters worse, parts books are often incorrect on TFI module applications! With the incorrect TFI module installed, the vehicle will run, but driveability and MIL (malfunction indicator lamp) problems will result. For instance, if a gray Push Start TFI module is installed in a CCD system, the computer will not be able to control ignition dwell, and the MIL will illuminate with memory codes for the IDM circuit set, as the gray TFL module is incapable of generating an IDM signal to the computer. If a black CCD TFI module is installed in a Push Start system, dwell will remain fixed, since the SPOUT signal duty cycle never changes. If in doubt about which TFI module belongs on a particular vehicle, consult the ignition system wiring diagram for the vehicle. If the wire going to pin #4 on the EEC-IV computer comes directly from pin #4 of the TFI module, it is a CCD system. If not, it is a Push Start system.
Ford TFI modules: Gray or Black?
Most technicians who deal with Ford driveability and no-start problems have become very familiar with the Thick Film Ignition (TFI) system. Ford started using the six-pin TFI module with the EEC-IV computer system in 1983, and for years it remained basically unchanged.
The early TFI system, which Ford calls the "Push Start" TFI system, uses a gray TFI module. Originally, the module was mounted on the distributor. In the late '80s Ford began to relocate it away from the distributor on some vehicles to provide better protection from the effects of engine heat, but system operation remained the same. It uses a Hall effect pickup (stator) in the distributor, which generates a battery voltage, 50% duty cycle square wave, called the PIP signal, to the EEC-U PCM and the TFI module. The PCM processes this signal and sends out another battery voltage, 50% duty cycle square wave, called the SPOUT signal, to the TFI module. As long as the TFI module is receiving a SPOUT signal, it will fire the coil at the rising edge of that signal (except during engine cranking, when SPOUT is ignored) and the vehicle will run with the amount of timing advance commanded by the computer. If the TFI module does not receive the SPOUT signal, it will fire the coil at the rising edge of the PIP signal, a nd the vehicle will run at base timing. This is true on all TFI systems.
Ignition dwell with the Push Start (gray module) system is controlled by the TFI module alone, and increases with engine rpm. The Ignition Diagnostic Monitor (IDM) signal on a Push Start TFI system comes from the coil negative circuit and is filtered through a 22k ohm resistor to pin #4 on the EEC-IV computer. The computer monitors this circuit to verify a coil firing for each PIP signal, and sets codes if it sees missing or erratic signals. Another feature that is unique to the Push Start TFI system is the start input on pin #4 of the module connector. This is wired into the starter relay trigger circuit, and signals the TFI module that the engine is cranking. When the module sees battery voltage on this circuit, the SPOUT signal is ignored.
In the early '90s, Ford began using a different TFI system on certain vehicles--the Computer Controlled Dwell (CCD) TFI system. The TFI module on CCD TFI is always black in color. There are a few major differences between the two systems. As the name implies, with the CCD system, the computer controls primary dwell. The CCD TFI module still ungrounds (fires) the coil at the rising edge of the SPOUT signal, but now the falling edge of the SPOUT signal (which had no meaning to the Push Start TFI module) is used by the CCD TFI module to ground the coil. The PIP signal remains the same 50% duty cycle square wave, but SPOUT signal duty cycle varies according to how much dwell is desired by the computer.
Another major difference between the two systems is the IDM circuit. Pin #4 on the CCD TFI module, which was the start circuit input on the Push Start TFI module, is now the IDM signal, sent directly from the TFI module to pin #4 on the EEC-IV computer. This signal is still a filtered (low voltage) version of the ignition primary waveform, but is filtered internally in the TFI module rather than through an external resistor. There isn't any start circuit input to the CCD TFI module; the module infers engine cranking from a low rpm input from the PIP signal.
Since these two TFI systems are so significantly different, yet so similar in appearance, parts application problems will inevitably occur. A gray Push Start TFI module will plug right into a CCD system, and vice versa. To make matters worse, parts books are often incorrect on TFI module applications! With the incorrect TFI module installed, the vehicle will run, but driveability and MIL (malfunction indicator lamp) problems will result. For instance, if a gray Push Start TFI module is installed in a CCD system, the computer will not be able to control ignition dwell, and the MIL will illuminate with memory codes for the IDM circuit set, as the gray TFL module is incapable of generating an IDM signal to the computer. If a black CCD TFI module is installed in a Push Start system, dwell will remain fixed, since the SPOUT signal duty cycle never changes. If in doubt about which TFI module belongs on a particular vehicle, consult the ignition system wiring diagram for the vehicle. If the wire going to pin #4 on the EEC-IV computer comes directly from pin #4 of the TFI module, it is a CCD system. If not, it is a Push Start system.
Last edited by RPetty_43; Jan 17, 2016 at 01:08 PM.
That's a good article. Thanks for posting it. I'm going to have to save it and try to fully understand it later.
I had heard that the automatics got black ones and the manuals got grey ones - so they could be push started.
But it may be a little more complicated than that, so this will be good reading for a quiet day.
I had heard that the automatics got black ones and the manuals got grey ones - so they could be push started.
But it may be a little more complicated than that, so this will be good reading for a quiet day.
Senior Member
Joined: Dec 2014
Posts: 1,037
Likes: 141
From: South Dakota
I'm not sure where the push start term comes in, yes I know it is used. With a manual transmission, they should be able to be push started regardless, as long as the engine is able to turn while moving the truck. This is to the best of my knowledge anyway unless I'm missing something.