Fuel smell?

Tiny
HONDO97
  • MEMBER
  • 2005 FORD F-150
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 225,000 MILES
I recently changed the coil pack on the number two cylinder, but did not change the existing spark plug. The new pack didn’t seem to seat as low as the previous pack. Now there is a faint smell of gas in the cab with the A/C on. What could cause this? Spark plug loose? Pack not seating?
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Saturday, October 26th, 2019 AT 10:21 PM

7 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,005 POSTS
Welcome to 2CarPros.

Is there a misfire? As far as the coil, in and of itself, it won't cause a fuel smell unless it is not firing and allowing unburned fuel to exit through the exhaust.

Let me know if there is a misfire.

Joe
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Saturday, October 26th, 2019 AT 11:26 PM
Tiny
HONDO97
  • MEMBER
  • 2 POSTS
Yes, cylinder two had a misfire code and the engine was not idling smoothly. I haven’t checked the code again. The smell was noticed during the drive to clear the code. The truck is idling smoothly now.
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Sunday, October 27th, 2019 AT 5:25 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,005 POSTS
Welcome back:

Okay, since the coil has been replaced and the misfire is gone, that problem is taken care of. The smell is a different issue not caused by the coil or a loose spark plug. However, if the plug is loose, it should be tightened.

Have you checked under both the hood and vehicle for possible fuel leaks? Also, if you open the hood, do you see any vacuum hoses disconnected? Also, can you tell me if the check engine light is still on? This smell could be an EVAP leak, but normally that will set a code.

I attached a pic of the EVAP canister located under the truck. Check to make sure there are no cracked, damaged, or disconnected hoses going to it. If there is, that will produce a fuel smell. Also, the hoses do route to the engine compartment, so you have to do the same there. Check around the intake manifold (top of engine) and along the inner fenders to check for issues.

Please keep in mind, an EVAP leak is nothing more than a fuel vapor leak. However, that too can be dangerous. Also, make sure there are no actual fuel leaks at the injectors, fuel rail, and so on,

Let me know what you find.

Joe
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Sunday, October 27th, 2019 AT 8:38 PM
Tiny
ROBERT T
  • MEMBER
  • 1 POST
  • 2005 FORD F-150
  • V8
  • 4WD
  • AUTOMATIC
  • 49,000 MILES
The gas smell comes through the defrost and vent cycles only when vehicle is at an idle. All hoses, on leaks at rails or injectors, any suggestions?
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Saturday, May 29th, 2021 AT 11:01 AM (Merged)
Tiny
BMDOUBLE
  • MECHANIC
  • 1,139 POSTS
The 5.4 3v engine spark plugs are known to come loose after a tune-up. Sometimes a little bit of dirt will fall under the mating surface between the head and plug and consequently the plug will not fully seat and come loose. I just repaired one for this issue and the exhaust fumes were shooting straight out of the plug hole and the customer complained of a fuel smell when at a stop.
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Saturday, May 29th, 2021 AT 11:01 AM (Merged)
Tiny
MARCO09
  • MEMBER
  • 1 POST
  • 1998 FORD F-150
I have changed the engine and now have a problem with gas leaking from the #4 injector into the manifold. What can I do to fix this problem?
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Saturday, May 29th, 2021 AT 11:01 AM (Merged)
Tiny
DAVE H
  • MECHANIC
  • 13,383 POSTS
FUEL RAILS & INJECTORS
Removal & Installation
Release fuel pressure. See FUEL SYSTEM PRESSURE RELEASE . Disconnect negative battery cable. Disconnect vacuum hose from fuel pressure regulator. Remove fuel hose clamps.
Disconnect fuel supply and return line connections at fuel supply manifold. Disconnect fuel injector wiring harness connectors. Remove PCV hose.
Remove EGR valve-to-exhaust manifold tube. Disconnect EGR valve and EGR transducer hoses. Disconnect Vapor Management Valve (VMV) hose. Remove fuel supply manifold retaining bolts. Remove fuel supply manifold with injectors by pulling on injectors while using a rocking motion. Carefully disengage fuel injectors from supply manifold. To install, reverse removal procedure. See Fig. 3 .
Fig. 3: Exploded View Of Fuel Injection System


https://www.2carpros.com/forum/automotive_pictures/266999_inj_2.jpg

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Saturday, May 29th, 2021 AT 11:01 AM (Merged)

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