Complete shut down w/code C-18

Rdub6

So while I wait to figure out my rear end issues
Dec 29, 2017
3,142
2,385
143
Long Island, NY
That’s exactly it, it’s going to be something very stupid when found but finding it is the annoyance.
When it’s finally found I will share in this thread in hopes of saving others time and money. What will ultimately fix it for me may not necessarily be the solution for others with the same problem because there are many causes for this problem but at least I can provide recent credible info at minimal for others once mine is solved. I tried everything others suggested to me but so far no luck so maybe I will have a different solution that will be helpful to others. Time will tell.
We’re geographically close in Stangnet terms, but I wish we were closer, and I’d lend whatever hand I could. It’s going to be something simple for sure....... it’s just a matter of finding it. Or the right new set of eyes on something everyone else is overlooking.
 
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91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
407
241
53
Lake George NY
Car dying only once fully up to temp screams bad TFI to me. The engine will start once it has a chance to cool back down.

The fix...
Clean the distributor and make sure it's making good contact to the engine block. Replace the TFI and use extra thermal paste, the TFI going bad will cause a lack of spark even with an msd box installed.

The tfi on a fox is gray in color and should NOT be ccd (computer controlled dwell)

Now the coil could be overheating but this is much less likely.
Coil, TFI with paste and distributor are all brand new.
Car dies every few miles but doesn’t need to cool down to re-start. She fires right back up and all is fine for another few miles until it happens again and again and again.
Car dying only once fully up to temp screams bad TFI to me. The engine will start once it has a chance to cool back down.

The fix...
Clean the distributor and make sure it's making good contact to the engine block. Replace the TFI and use extra thermal paste, the TFI going bad will cause a lack of spark even with an msd box installed.

The tfi on a fox is gray in color and should NOT be ccd (computer controlled dwell)

Now the coil could be overheating but this is much less likely.
TFI/Paste, coil, distributor are all new.
Shuts down every few miles but doesn’t need to cool down at all. It starts right back up and drives perfect for another few miles until it happens again. Same drill over and over but never has to cool down.
 

91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
407
241
53
Lake George NY
We’re geographically close in Stangnet terms, but I wish we were closer, and I’d lend whatever hand I could. It’s going to be something simple for sure....... it’s just a matter of finding it. Or the right new set of eyes on something everyone else is overlooking.
Hey Rdub6, I appreciate that! Nice of you to offer help!
I think your right about sometimes it takes a new set of eyes. The past few guys tried hard and were very knowledgeable and hit on all the right possibilities but unfortunately it didn’t work out. This next stop has access to more equipment so I’m confident (again) that this will be solved. The more that look at it the better my chances are for a fix. Let’s see what happens come December when it’s looked at again. I hope to have some good info to share with all.
 
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90sickfox

Wasn't a pretty sight...and I've got big hands
SN Certified Technician
Mar 2, 2015
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I've seen a father relay do that. It was just barely making contact. Certain bumps would make it break contact.
 

91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
407
241
53
Lake George NY
I've seen a father relay do that. It was just barely making contact. Certain bumps would make it break contact.
Father relay?
The fuel pump relay is 8 months old and the computer power relay is one week old.
Is the father relay one of those or something different or maybe just a typo?
Although the fuel pump relay is only 8 months old maybe I should swap it out again In case it’s a Bad aftermarket? I hesitated to do that because I’m thinking it’s a ground issue somewhere and knowing it’s not old. Well, Maybe I should do this anyway (thinking out loud).
 

Rdub6

So while I wait to figure out my rear end issues
Dec 29, 2017
3,142
2,385
143
Long Island, NY
Father relay?
The fuel pump relay is 8 months old and the computer power relay is one week old.
Is the father relay one of those or something different or maybe just a typo?
Although the fuel pump relay is only 8 months old maybe I should swap it out again In case it’s a Bad aftermarket? I hesitated to do that because I’m thinking it’s a ground issue somewhere and knowing it’s not old. Well, Maybe I should do this anyway (thinking out loud).
Sorry for not reading back on everything, so this probably was addressed, but have you checked ALL the grounds.
 

Rdub6

So while I wait to figure out my rear end issues
Dec 29, 2017
3,142
2,385
143
Long Island, NY
Yes. Even took a bunch off and scraped the paint off down to raw metal again to ensure contact. Tightened screws, etc.
Damn...... hope you get this figured out.

I’m just wondering if heat has something to do with it. Maybe as things get hotter connections expand? Shut it off for a minute they contract and make contact again? Just thinking out loud myself here!
 

91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
407
241
53
Lake George NY
Damn...... hope you get this figured out.

I’m just wondering if heat has something to do with it. Maybe as things get hotter connections expand? Shut it off for a minute they contract and make contact again? Just thinking out loud myself here!
Could be. At this point anything is possible I guess. That theory would make sense. I kinda overloaded my brain thinking and reading about it. The more I think and read the more possibilities of what it can be comes up and that rabbit hole gets deeper and deeper. Lol
I’m also thinking it may actually be the computer. I hope not but maybe leaking capacitors on the board. The next spot I take it to is going to swap mine for a known working computer to test and see what happens.
I use to hear all the selenoids click when I did the key on/engine off test but now I only hear 1
Click and then nothing else. That’s kind of weird also I think. Airbag light started flashing (10 times) around the same time (2 weeks earlier) that this “shut down” issue started. Not sure if connected but I guess anything is possible. Ground or computer issue I’m thinking.
 

91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
407
241
53
Lake George NY
The more hands that touch this. Well anyway,
When it shuts down, do you turn the key off then start the car?
When it shuts down while moving I push up into neutral (AOD) then turn the key completely back/off then turn right back forward/on and she starts right up. I then push down into drive and keep moving.
 

91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
407
241
53
Lake George NY
Ya know what General, I didn’t look at that and I didn’t hear anyone else that looked at it mention they checked it or that it was a Possibility. That part didn’t cross my mind until now that you mentioned it. I just did some Quick reading to familiarize myself more with the functions of this switch and I think you may be onto something.
Thanks for your answer. Seems a strong possibility you could be right! Im going to pick one up and see what happens. I like this answer! Thank you!
 

90sickfox

Wasn't a pretty sight...and I've got big hands
SN Certified Technician
Mar 2, 2015
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That was a typo. Was rushing for time and let my smart phone slip in " father " in front of relay. Damn dumb smart phone.
 
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Jan 30, 2021
25
6
13
Pornville
My car did that for a while, and could do it again at any time. Salt and pepper shakers loose contact. I have to get out of the car, and shake em up. Then off I go. It could happen anywhere, anytime. Shake the shakers.
 

91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
407
241
53
Lake George NY
My car did that for a while, and could do it again at any time. Salt and pepper shakers loose contact. I have to get out of the car, and shake em up. Then off I go. It could happen anywhere, anytime. Shake the shakers.
Those were tested as well as their connections and found to be in order.
Thank you for letting me know about that though.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
23,057
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polk county florida
Yeah run right out and buy another part.
Could be loose wire.
Could be the fuse link that is weak.
Could be the nut behind the wheel is loose.
Look at the switch, start the car let it run a while, at least three songs on a Rolling Stones CD, slightly move the key switch around and wiggle the connector at the switch.
Most times there are burnt connections and melted plastic so it maybe visible, Ford did a recall or TSB on it.
I've replaced mine twice, I'm surprised this was not mentioned before, classic symptom.
 
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Dan02gt

mazing how much gas smell came from that tiny hole
10 Year Member
Mar 2, 2003
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Greenville, NC
You might have already covered this but check the power and ground wires on the 60 pin ECU connector. Mine had a issue where you could just touch one of them and the car would shut off. I ended up buying a new 60 pin connector and swapped them, tightening each physical connection as I moved it to the new connector.