ELECTRICAL ISSUE--TFI?? IGNITION?? OR?? - Ford Mustang Forums : Corral.net Mustang Forum
 
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post #1 of 14 Old 11-12-2016, 04:18 PM Thread Starter
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ELECTRICAL ISSUE--TFI?? IGNITION?? OR??

I have a 92 Mustang GT 5.0 and I've been having a random issue where I'm driving down the road and all of a sudden it just turns off, kind of like someone turned the ignition switch off. It will usually turn right back on by itself within 5 seconds, give or take. This morning I was driving on the highway and the radio cut out (shut off) for a half a second then came right back on; it did this twice. Then a half a minute later, the car shut off for about 2 seconds then came right back on.

I'm pretty positive it's an electrical issue somewhere, but my question is where? Is this possibly the TFI that's mounted on the front of the distributor? Is it something inside the distributor cap? Is this an ignition switch issue? Starter solenoid?? I'm not sure where to start diagnosing or how to diagnose whichever part is in question. In other words, if the TFI is going bad, is there a way to test it before spending the money on a new one just to find out that wasn't the problem? Any help is appreciated. Thanks...

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post #2 of 14 Old 11-16-2016, 02:08 AM
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the radio should clue you in that its not likely, tfi

engine off key in run, radio should remain on

you have an inter open somewhere, that reveals itself from heat and/ vibration

no easy way but to use your wiring diagram, and start at locations subject to heat and vibration.


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post #3 of 14 Old 11-16-2016, 08:48 AM
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Could loose wires near the starter solenoid be a decent place to check?
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post #4 of 14 Old 11-16-2016, 10:58 PM
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yeah, or even a partial blown fuse link.

89 GT gr-40, KB2200(10psi), tweecer R/T,LC-1, 22gal cell, w/tailpipes.
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post #5 of 14 Old 11-16-2016, 11:09 PM Thread Starter
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Indy2000: What you said makes a lot of sense. I really hope you're wrong though. Electrical issues and I don't get a long. I struggle troubleshooting electrical issues, especially in a situation like you're describing. However, inspecting the fuses is not a problem.

5.0 Thunder: I'll check that wire. That's easy enough.

Thanks for the advice guys....
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post #6 of 14 Old 11-17-2016, 04:17 PM
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Quote:
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Indy2000: What you said makes a lot of sense. I really hope you're wrong though. Electrical issues and I don't get a long. I struggle troubleshooting electrical issues, especially in a situation like you're describing. However, inspecting the fuses is not a problem.

5.0 Thunder: I'll check that wire. That's easy enough.

Thanks for the advice guys....
Fuselinks are not fuses & you have to know what you're looking for if inspecting them.

http://www.autozone.com/repairguides...00c152801e4c04

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post #7 of 14 Old 11-18-2016, 12:49 AM Thread Starter
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Fuselinks are not fuses & you have to know what you're looking for if inspecting them.

http://www.autozone.com/repairguides...00c152801e4c04
Thanks for that diagram. So that's what I should be looking for? I presume I should start looking under the hood for such a wire since it's easier to access than behind the dash. However, in an effort to narrow down my search, should I be focusing on wires in the ignition system or could it be any wire causing the issue I'm having? Logic tells me I should focus on the ignition system, including the distributor, starter, starter solenoid, etc.....Am I on the right track?
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post #8 of 14 Old 11-18-2016, 10:51 AM
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I would cbeck tbe ignition switch under the shielding .
Not the key, the switch.
These are known to seperate and cause problems just as you described .
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post #9 of 14 Old 11-19-2016, 01:25 AM Thread Starter
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I would cbeck tbe ignition switch under the shielding .
Not the key, the switch.
These are known to seperate and cause problems just as you described .
I'll definitely check the switch. Thanks for the advice....
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post #10 of 14 Old 11-22-2016, 10:22 AM
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Thanks for that diagram. So that's what I should be looking for? I presume I should start looking under the hood for such a wire since it's easier to access than behind the dash. However, in an effort to narrow down my search, should I be focusing on wires in the ignition system or could it be any wire causing the issue I'm having? Logic tells me I should focus on the ignition system, including the distributor, starter, starter solenoid, etc.....Am I on the right track?
Most of the fuselinks are attached to the starter relay.

The ignitions switches had a recall back in the mid-90's. Any Ford dealer can look up your VIN to see if yours was replaced. If not, they may still do it for free. Safety recalls do not expire.
95S28 NOV 95 Safety Recall 95S28 - Ignition Switch Replacement


1988 GT, 57k mi, Orig Owner
ProCharger P600B, FRPP Headers, Flowmaster F2, 3G Alt, Mk8 Fan/DCC, 3.55's, Prog Springs, ST Brace, G/Trac Bar, Subfrms, UCA, LCA, FCA, Tokico 5-ways, C/C Plates, CSA 16x8, Bridgestone RE760 Sport 225/50R16, Megasquirt DIYPNPF60, LC2 WBO2, C&L76mm MAF w/LU47's
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post #11 of 14 Old 11-22-2016, 10:13 PM Thread Starter
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Most of the fuselinks are attached to the starter relay.

The ignitions switches had a recall back in the mid-90's. Any Ford dealer can look up your VIN to see if yours was replaced. If not, they may still do it for free. Safety recalls do not expire.
95S28 NOV 95 Safety Recall 95S28 - Ignition Switch Replacement
Thanks for that valuable info. I'll definitely look into that....Question, if none of the fuse links at the starter relay are frayed or look damaged, how do you determine if there is a problem with them or not? How do you test for a damaged fuse link? Ohm meter? If so, what ohms should it read?
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post #12 of 14 Old 11-23-2016, 12:57 AM
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do NOT use an ohm test

you perform a voltage drop across that link, with the circuit energized

one lead on one side the other lead on the other side.

you are trying to see if the link can carry the proper current, your ohm meter puts out very LITTLE current, therefore is a useless test.

ohm testing is good for shorts

89 GT gr-40, KB2200(10psi), tweecer R/T,LC-1, 22gal cell, w/tailpipes.
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post #13 of 14 Old 11-25-2016, 01:26 AM Thread Starter
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do NOT use an ohm test

you perform a voltage drop across that link, with the circuit energized

one lead on one side the other lead on the other side.

you are trying to see if the link can carry the proper current, your ohm meter puts out very LITTLE current, therefore is a useless test.

ohm testing is good for shorts
I assume I'm looking for 12v across the wire? Is there a range that's acceptable?
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post #14 of 14 Old 11-25-2016, 09:35 AM
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you are looking for less than 0volts for good

if you have battery voltage across that , the fuse is OPEN, blown

89 GT gr-40, KB2200(10psi), tweecer R/T,LC-1, 22gal cell, w/tailpipes.
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