charcoal canister removal?

[Mustang5L5]

Varying conditions would dictate if you smell fumes or not. Typically it's when the tank is cold, and then it heats up. As the fuel and vapor expands, it would then be pushed out of evap line and into the charcoal canister. When it cools, fresh air would draw back through it into the car (somewhat saturating with fuel vapor as well). Under some conditions, you won't get any vapor.

 

[Scrapla347]

Some do some don't, ... personally if it was clogged/saturated or just missing I would have just let it vent to atmosphere but I figured since I had it might as well leave it in

That was my reasoning as well. I have it so I figured I would keep it. It's funny how one project always leads to another.

 

[Scrapla347]

Varying conditions would dictate if you smell fumes or not. Typically it's when the tank is cold, and then it heats up. As the fuel and vapor expands, it would then be pushed out of evap line and into the charcoal canister. When it cools, fresh air would draw back through it into the car (somewhat saturating with fuel vapor as well). Under some conditions, you won't get any vapor.

I hate to throw things away from this car so I'm happy to keep it.

 

[Noobz347]

To keep a purge solenoid for your Termi-X ECU:

Hardware Setup​

Solenoid:

• Use a GM EVAP purge solenoid (common, cheap, PWM friendly).
• It’s a simple 2-wire coil, normally closed.
• Wiring:
  • One side → switched 12V (IGN ON, fused).
    Other side → any available low-side output (ECU grounds it to turn on).
  • Common spare pins: PWM1, PWM2, or configurable Output 1/2 depending on your harness.
    
• Mount it inline:
  • Tank vent → Charcoal canister → Purge Solenoid → Intake Manifold Vacuum
    
    

---

ECU Configuration (Holley V4 Software)​

1. Open Holley EFI software → Toolbox → System Parameters.
   
   
2. Go to Inputs/Outputs ICF.
   • Add a “Custom Output”.
   • Assign it to the output pin you wired (e.g., PWM1).
     
3. Set Output Type:
   • Mode: PWM
   • Frequency: 15 Hz (10–20 Hz works, but 15 Hz is a sweet spot for GM solenoids).
   • Output Polarity: Normal (Active Low)
     
     
4. Define Enable Conditions (Basic):
   • CLT > 150°F
   • RPM > 1200
   • MAP between 35–70 kPa
   • TPS < 35%
   • Idle State = OFF
   • DFCO = OFF
     
     
5. Build a Duty Table (Duty vs MAP):
   

   MAP (kPa)	Duty %
   30	10%
   40	20%
   50	30%
   60	40%
   70	45%

   (Cap duty around 45–50% — enough purge to keep the canister dry without upsetting fueling.)
   
   
6. Optional Hot-Soak Adder:
   • Use “Time Since Engine Start” as a condition.
   • If CLT > 180°F and IAT > 120°F, add 10–15% duty for the first 90 seconds after startup.
     

Testing​

• Key ON, engine OFF: solenoid should click briefly if you use an “Test Output” in the software.
  
  
• Engine running, warm: in Data Monitor, log PWM duty and verify purge occurs only under your enable window.
  
  
• Datalog fuel trims with purge enabled. If LTFTs swing >10% during purge → reduce duty by 5–10% or narrow the MAP window.

​

​

Wrap-Up Checklist​

• Solenoid powered from switched 12V, ECU low-side wired correctly
  
  
• Output set to PWM @ 15 Hz
  
  
• Enable conditions: CLT > 150°F, RPM > 1200, MAP 35–70 kPa, TPS < 35%
  
  
• Duty cycle table built (10–45%)
  
  
• Hot-soak purge adder configured (optional)
  
  
• Verified no idle drift, trims stable, no hot restart fuel smell

--------------------------------------------------------------------------------------------------------

Quick Reference Drop-In values (same info as above):
Holley Terminator X – Purge Solenoid Setup


Custom Output Name: Purge Solenoid
Type: PWM
Output Pin: (choose the spare you wired, e.g. PWM1 Low-Side)
Polarity: Normal (Active Low)
Frequency: 15 Hz


Enable Conditions:

• CLT > 150°F
• RPM > 1200
• MAP between 35 and 70 kPa
• TPS < 35%
• Idle State = OFF
• DFCO = OFF

Duty Cycle Table (Duty % vs MAP):
30 kPa = 10%
40 kPa = 20%
50 kPa = 30%
60 kPa = 40%
70 kPa = 45%


Optional Hot-Soak Adder:

• Condition: CLT > 180°F and IAT > 120°F
• Time Since Engine Start < 90 seconds
• Duty Add: +10 to 15% on top of table

Testing:

1. With ignition ON (engine off), go to I/O Test in Holley software and manually toggle the Purge Output. Solenoid should click.
2. Warm up the car. In Data Monitor, “Custom Output Duty” should show 10–45% only when enable conditions are true.
3. Datalog with purge active. If long term fuel trims swing more than ±10% during purge, reduce duty table values 5–10%.

 

[Scrapla347]

To keep a purge solenoid for your Termi-X ECU:

Hardware Setup​

Solenoid:

• Use a GM EVAP purge solenoid (common, cheap, PWM friendly).
• It’s a simple 2-wire coil, normally closed.
• Wiring:
  • One side → switched 12V (IGN ON, fused).
    Other side → any available low-side output (ECU grounds it to turn on).
  • Common spare pins: PWM1, PWM2, or configurable Output 1/2 depending on your harness.
• Mount it inline:
  • Tank vent → Charcoal canister → Purge Solenoid → Intake Manifold Vacuum
    

---

ECU Configuration (Holley V4 Software)​

1. Open Holley EFI software → Toolbox → System Parameters.
   
   
2. Go to Inputs/Outputs ICF.
   • Add a “Custom Output”.
   • Assign it to the output pin you wired (e.g., PWM1).
3. Set Output Type:
   • Mode: PWM
   • Frequency: 15 Hz (10–20 Hz works, but 15 Hz is a sweet spot for GM solenoids).
   • Output Polarity: Normal (Active Low)
     
4. Define Enable Conditions (Basic):
   • CLT > 150°F
   • RPM > 1200
   • MAP between 35–70 kPa
   • TPS < 35%
   • Idle State = OFF
   • DFCO = OFF
     
5. Build a Duty Table (Duty vs MAP):
   

   MAP (kPa)	Duty %
   30	10%
   40	20%
   50	30%
   60	40%
   70	45%

   (Cap duty around 45–50% — enough purge to keep the canister dry without upsetting fueling.)
   
   
6. Optional Hot-Soak Adder:
   • Use “Time Since Engine Start” as a condition.
   • If CLT > 180°F and IAT > 120°F, add 10–15% duty for the first 90 seconds after startup.

Testing​

• Key ON, engine OFF: solenoid should click briefly if you use an “Test Output” in the software.
  
  
• Engine running, warm: in Data Monitor, log PWM duty and verify purge occurs only under your enable window.
  
  
• Datalog fuel trims with purge enabled. If LTFTs swing >10% during purge → reduce duty by 5–10% or narrow the MAP window.

​

​

Wrap-Up Checklist​

• Solenoid powered from switched 12V, ECU low-side wired correctly
  
  
• Output set to PWM @ 15 Hz
  
  
• Enable conditions: CLT > 150°F, RPM > 1200, MAP 35–70 kPa, TPS < 35%
  
  
• Duty cycle table built (10–45%)
  
  
• Hot-soak purge adder configured (optional)
  
  
• Verified no idle drift, trims stable, no hot restart fuel smell

--------------------------------------------------------------------------------------------------------

Quick Reference Drop-In values (same info as above):
Holley Terminator X – Purge Solenoid Setup


Custom Output Name: Purge Solenoid
Type: PWM
Output Pin: (choose the spare you wired, e.g. PWM1 Low-Side)
Polarity: Normal (Active Low)
Frequency: 15 Hz


Enable Conditions:

• CLT > 150°F
• RPM > 1200
• MAP between 35 and 70 kPa
• TPS < 35%
• Idle State = OFF
• DFCO = OFF

Duty Cycle Table (Duty % vs MAP):
30 kPa = 10%
40 kPa = 20%
50 kPa = 30%
60 kPa = 40%
70 kPa = 45%


Optional Hot-Soak Adder:

• Condition: CLT > 180°F and IAT > 120°F
• Time Since Engine Start < 90 seconds
• Duty Add: +10 to 15% on top of table

Testing:

1. With ignition ON (engine off), go to I/O Test in Holley software and manually toggle the Purge Output. Solenoid should click.
2. Warm up the car. In Data Monitor, “Custom Output Duty” should show 10–45% only when enable conditions are true.
3. Datalog with purge active. If long term fuel trims swing more than ±10% during purge, reduce duty table values 5–10%.

Awesome and thanks for sharing.

 

[Noobz347]

Awesome and thanks for sharing.

If you go this route, be sure to give me some feedback on the accuracy of the checklist.

It looks pretty straight forward but I don't have a Termi-X to test with.

I can create similar checklists for others that have well documented manuals.

 

[from6to8]

just put a V3 on my 94 and started smelling some fuel but it could be the car is a tad rich. The cannister isn't plugged up to the intake and no Egr or smog or anything, the line's look deteriorated. So I should just leave it as is as it's venting on it's on? It's not plugged up to the harness eitther.

 

[Mustang5L5]

The media might be over saturated. Hard to say. You might want to test by gently blowing some compressed air through a line into the canister and see if it flows and if you smell gas when you do that.

 

[from6to8]

The media might be over saturated. Hard to say. You might want to test by gently blowing some compressed air through a line into the canister and see if it flows and if you smell gas when you do that.

ok i'll try that. If if does then what? If it doesn't, then what? I did not smell any fuel when I was NA but with no cats/ect just the same ole smell that's notorious to smell like a mixture of fumes/ect with no cats and stuff. It seems different now.

Just made a few tweaks to some things on the car and when I drive it tommorow I'll see if anything I noticed before with anything with the car changes....

 

[Mustang5L5]

It should flow through and not haved too much of a fuel smell. If it doesn't blow through it's plugged. If it smells like pure gas it's saturated.

There are ways to regen it, but you'd have to research a safe method. However if it's saturated you might be pushing fuel through the evap line so something you might want to take a look at.

Rotted vac lines could also be the source and something to look at.

 

[from6to8]

It should flow through and not haved too much of a fuel smell. If it doesn't blow through it's plugged. If it smells like pure gas it's saturated.

There are ways to regen it, but you'd have to research a safe method. However if it's saturated you might be pushing fuel through the evap line so something you might want to take a look at.

Rotted vac lines could also be the source and something to look at.

So if the vac line is rotted is there something online that you know of of someone that's repaired it? If the line isn't rotted but the canister is saturated would another canister remedy it possibly? Like I said it's not hooked up to anything and it's unplugged but seems that's sufficient to vent if the line is good and if it isn't saturated?