Cam Change = Firing Order Change= Injector Change

Rjaaaaaa said:

TFI could this cause this type of problem? I couldn't compare it side by side because the original was melted but I do know it was grey.
I have good spark at the plugs so I don't see how the TFI could come into play.

Click to expand...

Here's a long,stolen post from another forum-some of the info isn't necessary for your situation-but basically explains what the tfi and pip actually do,and how I think its related to your issues.

I can't verify all info in this copied article (cause I didn't read it all )
Is correct-but mostly useful.

"push start", TFI module.
This module was used to control the dwell time of the ignition coil, and provide a "limp home" mode, at base timing, in
case the timed
spark signal to the module is lost. Ford refers to the trigger signal as
PIP, (profile ignition
pickup). It is produced by a hall effect sensor in the distributor at system
voltage, and has
it's rising edge at 10 degrees before top dead center on the crankshaft. In
the case of the
distributor I'm working on, the duty cycle is 50% for all cylinders except #
1, which is
35%. This is used to identify #1 for fuel injector sequencing in some
applications.
This PIP signal is sent to the TFI module, and the ECU, (engine control
unit).
Which uses it to calculate RPM, and as a camshaft position indicator to
calculate timed
spark. The SPOUT signal, (timed spark out), is an output at system voltage
and 50% duty
cycle, and is sent back to the TFI module. It is delayed from the point of
PIP, and
calculated to occur so that it's rising edge coincides with the desired
timing angle to fire
the coil for the following cylinder in the firing order. The rotor on the
distributor routes
the coil secondary current to the appropriate spark plug. The TFI module
fires the coil
when it receives a rising edge of SPOUT. If it does not receive a SPOUT
before the next
PIP, it will fire the coil on that PIP, (base timing, limp home mode). It
appears to charge
the coil only when PIP is low.
There is also an input the TFI module from the starter circuit which is
supposed to
provide increased dwell time during cranking to offset decreased system
voltage. Also,
some printed information available on the module has stated that if the
"start" input is not
present during crank, it will latch into "limp home" mode and stay there
until the key has
been cycled and start signal restored.
I am, along with some others, are trying to use this module with a home
built
engine management computer, "Megasquirt", in particular. I've taken some
existing
Megasquirt codes and have modified them so they should work with the TFI
module but
have run into some difficulties, probably because of my lack of
understanding on exactly
how this module works.
The discussion has come up as to how the TFI handles the dwell time, which
is
fairly basic theory.
It is my understanding that the primary winding of the coil is connected to
system
voltage for a short period of time, say 4 or 5 ms. During this time, the
current ramps up,
opposed by the induced voltage in the windings, up to a maximum steady state
current
determined by the resistance of the circuit. When it's time to "fire', the
circuit to the
primary is opened. The field collapses, inducing a high voltage in the
primary, and a
proportional higher voltage in the secondary.
In a conventional Kettering, (points) system. the current is limited by a
ballast
resistor in series with the coil primary, and the time available to charge
the coil due to the
points being open and closed by a lobe on the distributor shaft.
Information on the TFI module states that it controls dwell with current
control.
The question is, what is the value of this controlled current, and when
does it
occur?
I say, the amount of energy available to fire the coil depends, not only on
the
inductance of the coil, but the amount of current flowing in the primary, at
the time of
current break. This is usually limited to 4 to 6 amps.
So, my theory is, the coil is not actually charged until SPOUT is received
.. At this
point, it is charged and fired in quick succession.
Others have said, the coil can be charged to it's fully charged state, any
time
before SPOUT goes high, with the current still limited to about the same
value, but then
decreased to some milliamp value until time to fire the coil, then break the
current, and
the coil will fire.