Help! 95gt Cranks But Won't Start

[April5.0]

Hello All,
I have an automatic 95 GT and have been having a "cranks but won't start" issue for about a year. I've gone through the No Start Check List, replacing the battery, ignition switch, spark plugs, ignition module, coil, distributor (PIP), and am still not getting any spark off the coil. Before I have it towed to the shop to see if they can figure it out, any suggestions? A friend of mine thinks it could be in the factory alarm system? Any help will be much appreciated!!
Thanks!
April

 

[Moosee1955]

Number 16 fuse is for your alarm system. Check for voltage on both sides of fuse with meter or continuity light. I've got a dumb question, and please don't take offense, why would you change all those parts, and let this drag on a year. You are 100 percent sure your problem is spark related, not fuel? Have you pulled a plug wire at spark plug, checked spark down there? If you've gone through the full troubshooting chart, and came up blank, I wouldn't have thrown the cash at parts that the tests said were good. That said, try the fuse for your anti theft system first, you will need a flow chart to diagnose your alarm, or be able to dis arm it. I don't know your skill set on wiring, maybe one of the others can help with your wiring, and steps. I have an I phone with limited capabilities. Keep us posted on your results, hopefully sooner than next year! Moose.


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[April5.0]

Thanks for the help! I should have said in the beginning that all of my fuses are good. It's been a year, because thankfully my mustang is not my daily driver, and I only get to work on it on weekends, when theres's nothing else going on. Yes, we pulled a spark plug and there is no spark. The alarm system is unarmed, I've tried it in the valet mode and still no start. When I disconnected the alarm system it cut the ignition off so I could't tell what was going on. Like I said, this is just one last stab to see if I'm missing something before I get it towed to the shop. Any other suggestions are welcome!
Thanks!
April

 

[RaggedGT]

Are you sure it's a factory Ford alarm system?
I'm not for sure-but I didn't think Ford started using the pats system until '96- others will chime in to correct me lol

 

[Moosee1955]

1996 was the first year Ford started installing pats. On certain vehicles. If it's like my expedition you'll have a blinking light every couple of seconds on dash. You more than likely have an aftermarket alarm. You said you bypassed it and still no spark?


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[April5.0]

ok, I thought it was factory, but I guess it's dealer installed? It's ford brand and the key fob has a mustang on it. I haven't been able to bypass it, just disconnect it, which then acts as if it's armed. To bypass it or remove it all together it looks like I'd have to tear out under the dash on the driver's side, the wires to the ignition, which I think are pink and gray, go through dash and into the firewall and then disappear...

 

[RaggedGT]

What does your ignition key look like?

 

[April5.0]

top picture on the right (the smaller one with the ford logo)

 

[Moosee1955]

96 should be the first year of the chip key. So you can rule out someone putting a non chip one in there. That would stop spark. If you have gone through the no spark checklist, and all wiring and components passed, your alarm disconnect or repair would be next logical step.


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[RaggedGT]

top picture on the right (the smaller one with the ford logo)

I think I would look at the security box,and see if you can find a part number,or even a name. I'm kinda leaning towards that at some point a previous owner had an aftermarket alarm added into the factory keyless entry/Ford setup. With it having a valet switch and an ignition cut off-I'm betting you will find an aftermarket box under/around the column

 

[April5.0]

ok, thanks, should be able to check the alarm out further this weekend

 

[jrichker]

@April5.0
Since you didn't reply to the Cranks OK but no start checklist, I'll ask again.

With the ignition switch in the Run position, do you have 12 volts on the green/red wire at the ignition coil? Yes or No?

 

[April5.0]

With the ignition switch in the Run position, do you have 12 volts on the green/red wire at the ignition coil? Yes or No?

We tested that a while ago, and at the time, yes, we had 12 volts.

 

[April5.0]

here are some pictures of what the alarm system looks like, the light (and valet button) on the dash, the box under the steering wheel, the valet button under the dash, and the key and fob

 

[RaggedGT]

here are some pictures of what the alarm system looks like, the light (and valet button) on the dash, the box under the steering wheel, the valet button under the dash, and the key and fob

My next idea would be to take the security box down and look for a serial/part/Id number, then see if you can find a wiring diagram for that particular box

 

[jrichker]

If you do indeed have 12 volts at the red /green wire, then chasing the alarm is not going to be productive. The alarm circuit would prevent 12 volts from going to the coil to prevent the ignition from operating.

The other low voltage wire on the coil goes to the TFI module. On a 95 Mustang the TFI module is mounted on a heat sink away from the distributor. Check the wire coming from the distributor to the TFI module for broken wires or loose connections.. The TFI module will have 3 wires, check each wire for security of connection broken connector and visible damage at both ends of the wire.

The following are diagrams courtesy of Tmoss & Stang&2birds

TFI module wiring for 94-95 Mustang GT

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring; http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.

94-95 Mustang wiring diagrams
http://www.veryuseful.com/mustang/tech/engine/#95-95Diagrams

 

[April5.0]

ok great thanks! will hopefully be able to get to do some work on it this weekend, will let you know what I find out

 

[April5.0]

whelp, finally gave up and had it towed to a ford dealer, they're saying that they "think" it could be the PCM, but not 100% sure, that's just all that's left that could be causing the "no spark"... any thoughts?
thank you in advance