Cranks but doesn't start

liljoe07 said:

Top wire on the TFI should blink. If not, and the TFI test good. Then its the PIP sensor.
First....Verify that you have power at the #4 wire of the TFI with key on and cranking. And power at the #3 wire of the TFI while cranking only. Test the number 3 and 4 wires to the ignition ground(bottom wire on the TFI) when testing for power.

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Alright, so here's the deal:

My buddy and I just ran a little test on all of the wires that connect to the spout, which go to the TFI Module. Here's what we've come up with. Maybe somebody can decipher these results and point me in the right direction.

We did two tests per wire. One, was with the Key On (without cranking), and the other test was performed while the engine WAS cranking. Here's what we found:

Key ON

#1 - 10.68v

#2 - 11.7v

#3 - 0v

#4 - 11.87v

#5 - 11.88v




While Cranking

#1 - 3.5v

#2 - 4.8v

#3 - 8.3v

#4 - 9.5v

#5 - 9.56v


Does anybody have any idea if this means anything?

double post

By the way, if my MSD ignition box were to fail, could that possibly be a reason why I'm not getting any spark?

HISSIN50 said:

An ignition box can cause a no-spark issue.

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So far, I've eliminated the coil, the TFI module, and the ignition switch. And, according to the guy up at the auto parts store, the numbers that I've posted above (pertaining to the five wires that go into the electrical connector) are allegedly right where they should be. So, unless it's a computer issue (because I've certainly had some mice crawling around down by the passenger-side floorboard), the only thing left that I could think of, is the MSD ignition box.

liljoe07 said:

TFI tests look good to me. Top two wires look odd for some reason when not cranking. But its been awhile since I've done any tests myself. I may play around tomorrow and see if they are the same readings.

You have 3.5v at the top wire of the TFI. But is it blinking when cranking, or steady voltage? That's the key to it. Should be blinking.

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It was flashing 3.5, 0, 3.5, 0, 3.5, 0, etc. So, I guess that would be the equivalent of 'blinking', had I been using a test light, correct?

Two more questions:

1) If an ignition box starts to fail, can it progressively get worse (meaning, the car begins to run rough) before it actually goes kaputt, or is it one of those parts that either works fine or doesn't work at all?

2) Is there any way that I can test the box? I looked on the internet, and the only information I found was from MSD themselves, and they're saying that if I send them my ignition box they can test it for like $80 or something.

Also, I am getting a tach signal whenever I turn the engine over; I'm just not getting any spark. What in the world could this be? I'm about a week away from simply having this thing towed to the dealership, so that I can just be done with it.

It's not the coil, it's not the TFI module or PIP sensor (I don't think), and it's not the ignition switch. I'm thinking that it's either my computer, or the MSD ignition box.

If you remember back in November (which was the last time that my Mustang actually ran) I was able to start the car and it at least idled. But, that was really about all the car could do. If I gave it any gas at all the vehicle would simple refuse to climb into the higher rpms; as if it was simply unable to support itself above idle.

The car also died a couple of times while idling, prompting me to restart it.

Does that sound like a box going bad, or a computer issue of some sort?

liljoe07 said:

If you are getting a tach pulse, then check for spark at the coil wire. And check for power at the positive side of the coil. Cant remember is I said that already, so Im repeating it.

Also try and start it with the SPOUT plug out. Check for spark that way.

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There's no spark at the coil, and the car will not start with the spout unplugged. That was one of the first things I tried when running down the checklist.

There's no spark at all...anywhere. The TFI's good, the coil's good, and (allegedly) all 5 wires on the spout are reading the correct amount of voltage at the right time. So, what's left?

I'm pretty sure I keep hearing something about an 'ignition fuse' somewhere that could have blown, however I am unable to locate this alleged fuse. The diagram listed on the fuse box (underneath the steering column) does not list any fuse related to the ignition, so I'm sort of confused by this suggestion.

Is there an ignition fuse on this vehicle that I am unaware of?

In that case, the fusible links that are in the 2 wires going to the starter solenoid must be good, because the car actually 'turns over' whenever I turn the key; it's just that I'm not getting any spark.

Isn't that right?

The fusible links in the starter solenoid only determine whether or not the starter gets power, not whether or not I get spark, correct?

Alright, check this out. I'm going to attempt to solve my own problem here.

First, let's go with what we know:

1) My car will not start due to lack of spark (meaning; there is no spark).
2) However, the car did start/run back in November, although I could not get the motor to rev past idle (the first sign that something wasn't quite right).
3) Coil tested fine.
4) TFI module tested fine.
5) MSD ignition box is probably fine.
6) The computer is most likely fine.
6) All of the wires (computer, ground, etc.) are also most likely fine because the car did start back in November, which means that the current problem is most likely a result of a failed component, rather than a faulty wiring situation.
7) The motor turns over, which means that the ignition switch/fusible links are fine, otherwise the motor wouldn't be turning over in the first place.

The last thing I can think of, would be the PIP sensor.

If we go back to the charts I posted a week ago, which show the voltage readings of all 5 wires (minus the ground wire) that go into the TFI module, we find this:

While Cranking

#1 - 3.5V

#2 - 4.8V

#3 - 8.3V

#4 - 9.5V

#5 - 9.56V

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Now, I still haven't heard anybody confirm that these numbers are, in fact, where they should be. And, on top of that, jrichker's post here (from the "no spark" thread) suggests that the PIP signal level needs to be above 6.5V in order to trigger the computer.

jrichker said:

Spark with the SPOUT out, but not with the SPOUT in suggests a PIP problem. The PIP signal level needs to be above 6.5 volts to trigger the computer, but only needs to be 5.75 volts to trigger the TFI module. Hence with a weak PIP signal, you could get spark but no injector pulse.

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http://www.stangnet.com/mustang-forums/785575-no-spark.html

Is that correct? Because, mine is only reading (or flashing) 3.5V.

Matter of fact, I just got done reading another thread (on a Ford truck forum), which involved a guy who was having a very similar (ignition) problem with his truck. Found in the middle of this thread, was a post by another gentleman, who pointed out the fact that the PIP wire on the TFI should read at least 6VAC.

Again, mine is only reading 3.5V.

So, does this sound like it could be a viable explanation for why my Mustang isn't producing any spark, or am I completely off the mark here?

Is anybody else able to verify that the top wire on the TFI should be reading 6V?

Alright, so I'm heading out to my car today, to try to get her runnin' (once again). And, after doing a little reading on how to pull the computer codes (assuming there are any), it appears that the computer will show a code 14 if it is indeed the PIP sensor that has failed.

Here's my question:

In pulling the codes, is it assumed that the engine should be running during this process, or is it a 'key on engine off' situation?

I ask, because right now my car is in no position to start; let alone run.


Also, if somebody could provide an answer to this question...

Ike83 said:

Is anybody else able to verify that the top wire on the TFI should be reading 6V?

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...I'd appreciate it.