When I changed the oil in my car it smelled like gas. The oil had about 4k and approximatly 3k of that was with an ls6 intake and qtp headers installed and no tune. I didn't notice anything weird about the oil when I drained it or looked at it on the dipstick other than it smelled like gas. The oil pressure was also normal. I've done quite a bit of reading on here and it sounds like it could be a couple of thihngs 1. factory tune is dumping to much fuel in and its making its way to the oil pan, 2. I have a leaking injector and the fuel is leaking into the oil after I turn off the motor.

My understanding was that it's not a problem to run headers and an intake without a tune, simple because your not changing enough to throw off the tune that far. I just raced the car at the track and nobody noticed any kind of smoke coming out of the exhaust pipes so it doesn't look like its running that rich at wide open throttle but there are signs of it running rich as the paint has turned brown around the exhaust on the bumper. The motor seems to run strong and I trapped 107 which is 3 mph faster than before the mods.

As far as checking for a leaking injector I know I need to do a leak down check of the fuel rail but how can I tell an injector leak apart from the fuel psi just going down at a normal rate? I would assume that some of the pressure would eventually be releivied back to the fuel tank normally otherwise the fuel pump wouldn't be programmed to prime the system before start up. The only other option I can think of is to pull off the fuel rail and prime the system and see if any of the injectors leak (can this be done without removing the intake?).

What do you guys think is the cause of the fuel getting into the oil?

Thanks in advance for your help!

Brad

 

How hard do you drive it?

 

It's not my DD so it gets pushed around when I take it out for the weekends, but 2,400 miles on this oil was cross country driving on the interstate...

 

You may be looking too deep into this.

Most of the time when I have changed the oil in ANY car it had a small scent of fuel.

Sidenote: I would go get it tuned and find out what your A/F is to find out if you are super soaking your bottom end with the injectors. And if they are stock find out what the duty cycle is showing. Changing the intake and putting headers on will really whack a stock tune in most cases.

 

I hope you are correct and that I am reading into this to much but I always change the oil in my cars and have never noticed the smell of gas this strong before, I mean it really had a strong smell of gas to it that was not normal.

I'm plannig on getting a wideband and a tune in the very near future.

 

The headers and intake will throw off the factory tune. But if everything is correct with the install, most of the time they will run lean. Is it throwing any codes? If it has an air leak upstream of the 02's, it could make them think the car is running lean and over compensate by dumping fuel in it.

 

Another way to check for excess fuel dilution is to send an oil sample in for testing to someone like Blackstone Labs (there are others).

 

Sounds like tune is off to me and it is dumping fuel.. If it was acting funny (loading up or the like) I would guess o2s first and then (acting even worse) the MAF. But sounds like you just need a tune, whether it be dyno or a base tune until you get more mods.

 

I just ordered one from them, unfortunately I didn't save a clean sample from the last oil.

 

I do have some concerns about the intake leaking, but I tried the wd-40 trick and didn't hear the idle jump up any nore did I hear any leaks from the intake. Is there a better way to check for leaks?

Thats what I tend to agree with, but after reading about the leaking injectors and having what smelled like a lot fuel in the oil I thought that could be it as well.

I do have a check engine light but that's from deleting the egr, air and cats.... I haven't had the codes checked though so it could be something else, I'll try and take it by a parts strore and get it scanned just to be sure.

Thanks everyone for the help!

 

Its not always this but loose piston fit or poorly sealing rings can give you fuel smell without other problems like injectors leaking etc. My TA ALWAYS had a terrible gas smell at 3k oil changes for over 100k miles. It had a few loose pistons and used about 1 qt of oil evey 2k.

Another sure sign of loose piston fit-poor ring seal is DARK oil. It gets dark quick from all the combustion gases and carbon getting past the rings and pistons.

My Ta oil gets dark FAST while my newer Formula stays clean looking even after 4 k miles.

Another sign to look for is hard starting hot...if you have a injector leaking its going to start like ***. So if it starting ok and running ok its time to consider piston wear or fit and piston ring seal.

 

I would try to not over examine too much man.. Do the simplest thing and get the codes ran. After that (which is likely the problem) get a tune, base or dyno whichever you think is best for your situation.
If that doesn't solve your problem, then go to the more advanced and rare things that could cause this problem.

 

Not an LS1, but my oil always has somewhat of a gas scent when I drain it.

 

Easy, I know what the problem is.

 

I don't' think mine is using that much oil maybe a quart every 3k miles... Not sure you can correlate oil color to anything going on in the motor, every car I have ever owned the oil gets dark after a while. I've always understood that is a byproduct of modern oils having detergents in them. I should be able to see if I have a ring problem with a leak down check but I don't have the right tools to do that.

I used to have a foxbody with a 302 and I don't recall the oil ever smelling like gas.... not sure I ever paid that much attention to it though. It was also carbed though.

You're right, that's what I will plan on doing and see what happens from there.

Thanks for everyone's help!

Brad

 

It could be like a reverse blow by effect. I assume you are just running the stock PCV setup right? No catch cans or breathers right? Like I said earlier, I wouldnt worry too much about it. If the car was acting up then it may be time to dig deeper.

 

Enlighten me with your (most likely) predictable "funny to yourself" comment, please.

 

has to be a ford comment.

 

I just put a dual catch can setup on the car. But it's only been there for maybe a hundred miles of that oil change.

 

DUH!




They circled it!


Just kidding man... From what I can see your Fox looks really clean!
Was it THAT obvious it was coming?