05 Spark Plug - Gas Smell questions

CelticDevilDog · #1 03-08-2012, 09:35 PM

My 05 F150 5.4L 3V KR just recently had the spark plugs changed at 60K because we recently bought the truck and wanted to be sure to not run into the "broken spark plug issue". We had this done at a local reputable mechanic and didn't think anything else about it.

Almost a week later there was a gas smell in the cab and I did some research on this and other forums and figured it was the spark plug change. After a few weeks of my husband not believing there was a gas smell and finally me complaining that I wasn't going to drive it anymore until it was fixed he jumped in the cab and smelled the gas.

He took it back to the mechanic and asked him to torque the plugs down again per the results of my research and the mechanic said that they were already torqued to specs. And they couldn't find the source of the gas smell.

Fast forward two weeks and the gas smell is still there, so the hubby took it back to the mechanic and he found a TSB about the injectors causing the smell and told us to take it to Ford. We did and ford said that the plugs weren't torqued properly. This, of course, got my husband upset because the mechanic he trusts told him one thing and the stealership told him something else.

I pose this question to all the knowledgeable people here: How is it possible that spark plugs that are not torqued properly can cause a gas smell in the cab? I realize that this is a common problem but what is actually causing the smell to permeate the cab? Also, is it possible that Ford has a different torque spec than my mechanic would have for plugs?

Sorry for the long post, just trying to vent my frustrations with everyone else that is having this issue.

Quack Addict · #2 03-08-2012, 10:02 PM

I had the same gas smell after my plug change back in January this year. After searching on here and talking to a few people, I also returned to the mechanic who changed them. We checked them and four were loose. They had been torqued to factory specs when changed. The boots on the coil packs were the dead give-a-way as to which ones were loose.

Since they were re-torqued, I have had no issues. We even suspected that the fuel rail had been bumped and the o-rings were unseated.....but that was not the case.

If the plugs are torqued properly, try checking for a leak from the fuel rail and possibly change the o-rings in the rail.

Good luck!!!!

CelticDevilDog · #3 03-10-2012, 10:01 PM

Thanks for the reply. Yeah the trip back to the initial mechanic didn't yield any results, but the trip to Ford did. They said the plugs weren't torqued properly and torqued them. That seems to have fixed the issue.

I'm still confused as to why that would cause a fuel smell in the cab.

Quack Addict · #4 08-13-2012, 08:59 AM

When the plugs are not torqued properly excess fuel under pressure blows up from the combustion chamber and soaks the boots on the coil packs causing the smell of fuel.

It was very easy to figure out the loose ones like I said due to two of them being wet and the other two smelling strong of fuel.