[FutureGMFanboy]

Hey, I just started to smell gasoline every time my truck starts. Does anyone have any idea what this could be? She runs fine otherwise. I'm going to scan for codes later and see if anything shows up, but any ideas on where to start looking would be helpful. Thanks guys!

 

[Iceman62]

Start w/the obvious...follow fuel line and see if there are any leaks. Also, make sure your vent tube's not blocked. I'm sure more suggestions will follow shortly...good luck & no smoking in/near the truck! >.<

 

[colbyjohnson1994]

Check your fuel pressure regulator by pulling the vacuum line and smelling for fuel in the line or liquid fuel coming out of the top of the regulator. If there is either of those two, replace the regulator: http://www.355nation.net/forum/how-...1256-how-install-fuel-pressure-regulator.html

 

[Freeballin]

Check your fuel pressure regulator by pulling the vacuum line and smelling for fuel in the line or liquid fuel coming out of the top of the regulator. If there is either of those two, replace the regulator: http://www.355nation.net/forum/how-...1256-how-install-fuel-pressure-regulator.html

That might be a problem because he has a 2008 I5 with the pressure regulator inside the tank.

I would sniff the exhaust for any raw gas fumes on first startup and look under the vehicle for fuel leaks.

 

[colbyjohnson1994]

That might be a problem because he has a 2008 I5 with the pressure regulator inside the tank.

I would sniff the exhaust for any raw gas fumes on first startup and look under the vehicle for fuel leaks.

I am sorry, I didn't know they were any different haha. You learn something every day

As for further diagnosing...Check your O2 readings.

 

[FutureGMFanboy]

Thanks for all the responses, here is my update:

I started the truck this morning and immediately ran to the tailpipe. I didn't smell any unburnt fuel initially, but when I was getting up I caught a wiff. Nothing concerning so far. When I got back to the cab I did smell some unburnt fuel near the open driver side door. So later today I am going to try and find someplace not covered in black snow, so I can check for fuel leaks. I'm thinking that maybe it's a fuel leak somewhere under the hood. I can't find my scan gauge either, so I'm gonna order a new one to check the O2 readings, and for pending codes.

Also, make sure your vent tube's not blocked.

What's the vent tube? The EGR line?

Thanks guys, I appreciate the help.

EDIT: I just had a friend with a better sense of smell help me out. He smelled a little unburnt fuel from the tailpipe, but we both smelled a lot under the hood. I will look for leaks later.

 

[08Canyon]

Do you mean you smell a rich running vehicle smell or do you mean you smell actual gasoline?

 

[FutureGMFanboy]

Do you mean you smell a rich running vehicle smell or do you mean you smell actual gasoline?

Ah, I may have been using the wrong term, it smells like my old go-karts used to. So I guess rich running vehicle, but I don't see soot in the tailpipe. And under the hood the smell was very strong, not something I'm used to on a modern vehicle.

Actually I just remembered, when I changed the spark plugs a few weeks back one of them had a good bit of oil on it. Could the smell actually be burning oil?

 

[FutureGMFanboy]

Update: Still haven't had a chance to check for leaks, but I found my scan tool and checked the O2 sensors. One of them stays around .7 occasionally going up to .8 and down to .6, the other one bounces from .1 to .7 or .8. Do you guys think this could be the problem? I thought they are both supposed to stay around .7. Thanks again!

 

[Freeballin]

An O2 sensor won't cause a fuel smell on a cold start as they only fine tune the fuel mixture once warmed up.

 

[FutureGMFanboy]

An O2 sensor won't cause a fuel smell on a cold start as they only fine tune the fuel mixture once warmed up.

Thanks Freeballin, but is it normal for my O2 sensor to keep bouncing from .1 to .8? I thought that was a sign that it needs replacing.

EDIT: I was thinking of the downstream O2... I think my upstream one is probably fine, but I'm gonna recheck it tomorrow when cold, and see how long it takes to start operating. I didn't see any fuel leaks when I was looking earlier, but I think the smell was actually burning oil based on 08Canyon's comments.

 

[Freeballin]

It's normal for the upstream O2 sensor to fluctuate from .020 to .780 a couple times per second while cruising.

The general recommendation is to replace O2 sensors around 100,000 miles as they will deteriorate over time and the voltage swing will slow down.

 

[08Canyon]

I am not suggesting the smell of oil. My question was meant to clarify if it smelled like you had a fuel leak or a rich running system.

Suggestions given at the beginning were suggestions to identify a fuel system leak. So I wanted to see what you meant....that's all.

 

[FutureGMFanboy]

It's normal for the upstream O2 sensor to fluctuate from .020 to .780 a couple times per second while cruising.

The general recommendation is to replace O2 sensors around 100,000 miles as they will deteriorate over time and the voltage swing will slow down.

It fluctuated roughly every 2-4 seconds while idling, I haven't checked it while cruising yet. But I'm at 160k now, so I should probably change it just to be safe.

I am not suggesting the smell of oil. My question was meant to clarify if it smelled like you had a fuel leak or a rich running system.

Suggestions given at the beginning were suggestions to identify a fuel system leak. So I wanted to see what you meant....that's all.

My mistake, I worded that wrong. I think I wasn't smelling a fuel leak, which explains why I never found one. But I did remember that I saw a lot of oil covering one of my spark plugs, so that's why I was thinking that maybe the smell was burning oil. The smell is very similar to these old gas go-karts I used to race as a kid, or a lawnmower after it first starts. Thanks guys!

 

[Tman8371]

I had the same problem on my '04. I suspected the fuel pressure regulator was the culprit but there was no obvious signs but I went ahead and changed it and it took care of the problem.

 

[FutureGMFanboy]

I had the same problem on my '04. I suspected the fuel pressure regulator was the culprit but there was no obvious signs but I went ahead and changed it and it took care of the problem.

Damn, on the 08's it's in the tank, so I'm not sure if it's worth replacing at this point. The truck runs pretty well otherwise. I may replace the O2 sensor though just because of age the mileage.