unburned fuel odour

Hey all,
98 civic lx (canadian) 220000kms, 5 speed. I let the car sit for a 4-5 days, then took it for a boot on the highway yesterday. Today when I got
in and started driving, I noticed a definite unburned gas smell. Not so severe that it smells like its pouring out somewhere, but bad enough to bug me.
Any ideas? The car has 3 month old wires, 1.5 year old plugs, new dist cap and rotor in november. Mileage has been OK, not stellar, I get 460kms on 35 litres of gas, so about 12-13 KM/L or 28-32 Miles/US gall. Located in Canada. Have not run any injector cleaner for a while.
I did a visual inspection of the fuel system. No drips visible. Injectors looked OK. I was reminded that I am due for a fuel filter change, I have one sitting in my trunk I haven't gotten around to changing it as yet.
No hard starting, running fantastic, good acceleration etc etc... Just the odor.
Any ideas?
Terry
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x-posted to rec.autos.makers.honda, as this thread should have been in the first place

When you say "unburned gas", do you mean an actual raw gas smell, or an eye-searing, hydrocarbon stink from the exhaust?
Did you fill up recently? "Topping up" a bit too aggressively will cause raw gas vapors to exit the EVAP canister vent, although in your case that /should/ light up the MIL.
Any corrosion on the low-pressure fuel return line alongside the gas tank? Any drips on the driveway next to the left rear wheel?
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cause
that
tank?
The smell is coming from the engine bay. Its hard for me to tell if it is raw fuel or just unburned mixture. I would say closer to raw fuel, it was given me a headache. Its more than just a sulfury smell from the exhaust. Speaking of which, if it was coming from the exhaust, that would indicate an exhaust leak, right? Well I don't think i have one, and my exhaust manifold is pretty new, replaced on warranty...
I was actually very close to being empty tank today, haven't filled for about 2 weeks.
PS regarding the x-thread, sorry... not sure where to post where everyone will see it. I can't seem to get used to outlook express to view these damn things, so I am using Talkaboutautos.com, and there are 2 separate forums for hondas. What should I be using?
Thanks Tegger Terry
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so no ideas here tegger?
any other info helpful?
t
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Assuming it's actual raw gasoline, it can only come from the delivery side. The fuel is pumped up the high pressure line to the fuel filter to the fuel rail and into the injectors. Excess fuel passes through the fuel pressure regulator and goes back to the tank through the low-pressure line.
There are quite a few connections between the tank high-pressure side and tank low-pressure side, all of which can leak. The injectors are prevented from leaking only by O-rings at either end. They are just a press-fit in the fuel rail and the intake manifold.
All I can think of right now is to make sure all hoses and lines are correctly connected, not corroded or split, and the fuel injectors aren't leaking at any of their top O-rings.
Start your observations at the fuel rail, and follow the lines back.
Sorry I can't offer more, but I don't know if there's a common failure mode on this car that would result in a fuel smell in the engine compartment.
I know your exhaust manifold was replaced, but has anybody ever done any work on the intake side?
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By the way, has this car ever been in a collision or had the engine removed? Either occurrence can result in pinched or otherwise damaged hoses and lines.
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I will check my injectors. They have never really been serviced, and I am interested in seeing what kind of shape they are in anyways.
The car has been in a couple collisions, but nothing serious. No the engine has never been removed.
Thanks t
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Check the evap system as well, and make sure all the hoses are still connected and are not leaking.
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Hey Tegger,
Figured this one out! Seems that one of my valve cover bolts stripped its thread, and was not seated properly to seal the valve cover, allowing unburned combustion gases to escape, and ending up venting into the passenger compartment.
Now I gotta figure out a way to fix the damn thread... Probably a helicoil, but I can't find a place that will sell me just 1 M6x1 helicoil, they want me to buy the whole kit for $29.
Any ideas?
t
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