OBD 1 Code 18
5th Wheeling
Joined: Feb 2025
Posts: 38
Likes: 2
Code 18 is probably a real error since the engine is dying. A quick check with a meter will verify the IDM circuit is good or bad. Either way I doubt it is causing your stalling issue. Start the engine then start wriggling wires. Not sure if the ICM/TFI wires are inside a foil sheath like the 1992 and up truck are, but that shield is known to wear through the wire insulation and cause issues.
Hotshot
Joined: Jul 2020
Posts: 10,519
Likes: 2,654
From: Near Salt Lake City
Just because the TFI module is new, I would NOT assume that is Not the problem
Was it a Motorcraft module?
How about
Do the pinpoint testing for the code 18 with a star tester that will beep as you do the wiggle test like the book says
There's a good chance it is the processor at fault
Was it a Motorcraft module?
How about
Do the pinpoint testing for the code 18 with a star tester that will beep as you do the wiggle test like the book says
There's a good chance it is the processor at fault
5th Wheeling
Joined: Feb 2025
Posts: 38
Likes: 2
Just because the TFI module is new, I would NOT assume that is Not the problem
Was it a Motorcraft module?
How about
Do the pinpoint testing for the code 18 with a star tester that will beep as you do the wiggle test like the book says
There's a good chance it is the processor at fault
Was it a Motorcraft module?
How about
Do the pinpoint testing for the code 18 with a star tester that will beep as you do the wiggle test like the book says
There's a good chance it is the processor at fault
Hotshot
Joined: Jul 2020
Posts: 10,519
Likes: 2,654
From: Near Salt Lake City
If 3 modules, a fourth will do nothing for you IMO
Explain tach movement
That sounds like a processor issue
Run the vehicle outside where you can watch it run for 20 minutes while you have a beer or lunch
Have a spark tester on it as it runs
Verify it is losing spark and then dies or dies and is still sparking
Is the distributor cap, okay? No carbon tracking? How about the rotor? Look inside the shaft hole for carbon tracking on the rotor
If the rotor shorts out you get a no spark
The coil wire ohms out okay?
Explain tach movement
That sounds like a processor issue
Run the vehicle outside where you can watch it run for 20 minutes while you have a beer or lunch
Have a spark tester on it as it runs
Verify it is losing spark and then dies or dies and is still sparking
Is the distributor cap, okay? No carbon tracking? How about the rotor? Look inside the shaft hole for carbon tracking on the rotor
If the rotor shorts out you get a no spark
The coil wire ohms out okay?
5th Wheeling
Joined: Feb 2025
Posts: 38
Likes: 2
If 3 modules, a fourth will do nothing for you IMO
Explain tach movement
That sounds like a processor issue
Run the vehicle outside where you can watch it run for 20 minutes while you have a beer or lunch
Have a spark tester on it as it runs
Verify it is losing spark and then dies or dies and is still sparking
Is the distributor cap, okay? No carbon tracking? How about the rotor? Look inside the shaft hole for carbon tracking on the rotor
If the rotor shorts out you get a no spark
The coil wire ohms out okay?
Explain tach movement
That sounds like a processor issue
Run the vehicle outside where you can watch it run for 20 minutes while you have a beer or lunch
Have a spark tester on it as it runs
Verify it is losing spark and then dies or dies and is still sparking
Is the distributor cap, okay? No carbon tracking? How about the rotor? Look inside the shaft hole for carbon tracking on the rotor
If the rotor shorts out you get a no spark
The coil wire ohms out okay?
5th Wheeling
Joined: Feb 2025
Posts: 38
Likes: 2
If 3 modules, a fourth will do nothing for you IMO
Explain tach movement
That sounds like a processor issue
Run the vehicle outside where you can watch it run for 20 minutes while you have a beer or lunch
Have a spark tester on it as it runs
Verify it is losing spark and then dies or dies and is still sparking
Is the distributor cap, okay? No carbon tracking? How about the rotor? Look inside the shaft hole for carbon tracking on the rotor
If the rotor shorts out you get a no spark
The coil wire ohms out okay?
Explain tach movement
That sounds like a processor issue
Run the vehicle outside where you can watch it run for 20 minutes while you have a beer or lunch
Have a spark tester on it as it runs
Verify it is losing spark and then dies or dies and is still sparking
Is the distributor cap, okay? No carbon tracking? How about the rotor? Look inside the shaft hole for carbon tracking on the rotor
If the rotor shorts out you get a no spark
The coil wire ohms out okay?
5th Wheeling
Joined: Feb 2025
Posts: 38
Likes: 2
my issues all started after I got car back from muffler shop. They welded in 2 mufflers.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Hotshot
Joined: Jul 2020
Posts: 10,519
Likes: 2,654
From: Near Salt Lake City
That should not have caused any damage, but you never know
Maybe if they had the key on and then welded you might hurt the processor
Back when, we would just go to the junkyard and grab a processor
Expensive proposition now, swapping a processor on a whim, but that's what I'd probably do at this point
Maybe if they had the key on and then welded you might hurt the processor
Back when, we would just go to the junkyard and grab a processor
Expensive proposition now, swapping a processor on a whim, but that's what I'd probably do at this point
5th Wheeling
Joined: Feb 2025
Posts: 38
Likes: 2
That should not have caused any damage, but you never know
Maybe if they had the key on and then welded you might hurt the processor
Back when, we would just go to the junkyard and grab a processor
Expensive proposition now, swapping a processor on a whim, but that's what I'd probably do at this point
Maybe if they had the key on and then welded you might hurt the processor
Back when, we would just go to the junkyard and grab a processor
Expensive proposition now, swapping a processor on a whim, but that's what I'd probably do at this point
5th Wheeling
Joined: Feb 2025
Posts: 38
Likes: 2
That should not have caused any damage, but you never know
Maybe if they had the key on and then welded you might hurt the processor
Back when, we would just go to the junkyard and grab a processor
Expensive proposition now, swapping a processor on a whim, but that's what I'd probably do at this point
Maybe if they had the key on and then welded you might hurt the processor
Back when, we would just go to the junkyard and grab a processor
Expensive proposition now, swapping a processor on a whim, but that's what I'd probably do at this point
Hotshot
Joined: Jul 2020
Posts: 10,519
Likes: 2,654
From: Near Salt Lake City
I doubt it, both those codes are EVP codes
Shouldn't make the tach bounce or make the engine die
Sure, looks like it's idling so low, it is about to die
Wondering if the IAC works and if the base idle is set correctly or if the throttle plate has ever been messed with
How about the base timing?
Shouldn't make the tach bounce or make the engine die
Sure, looks like it's idling so low, it is about to die
Wondering if the IAC works and if the base idle is set correctly or if the throttle plate has ever been messed with
How about the base timing?
5th Wheeling
Joined: Feb 2025
Posts: 38
Likes: 2
I doubt it, both those codes are EVP codes
Shouldn't make the tach bounce or make the engine die
Sure, looks like it's idling so low, it is about to die
Wondering if the IAC works and if the base idle is set correctly or if the throttle plate has ever been messed with
How about the base timing?
Shouldn't make the tach bounce or make the engine die
Sure, looks like it's idling so low, it is about to die
Wondering if the IAC works and if the base idle is set correctly or if the throttle plate has ever been messed with
How about the base timing?
Hotshot
Joined: Jul 2020
Posts: 10,519
Likes: 2,654
From: Near Salt Lake City
Every Ford I've ever seen had you set the initial timing at 10 degrees with the spout out
Low timing will cause low idle speed and insufficient vacuum
Post a picture of the VECI that says that please
I'd start there
Low timing will cause low idle speed and insufficient vacuum
Post a picture of the VECI that says that please
I'd start there
5th Wheeling
Joined: Feb 2025
Posts: 38
Likes: 2
Here It is