After first noticing this problem, I searched around and found my flame trap popped apart with the bottom hose piece cracked/stretched out. I replaced the flame trap, holder and lower hose piece. For a while, the smell seemed to go away. An obvious problem with an obvious "fix", no?

But the smell is back. With the car just sitting on the driveway, if I start the car and step outside I smell it. Seems I can smell it inside the engine compartment. I can, of course, smell some at the tailpipe - but I expect that.

I have done all sorts of testing, searching all around this beast. No fluid leaking under the car, no obvious cracks/holes/gaps in the exhaust line, all hoses appear ok and connected under the hood. I have sprayed water over the intake components seeking leaks impacting idle and find none. I tested O2 sensor voltages (both the green wire and black), test grounding and applying voltage to the green O2 wire and got the expected results, checked AMM voltage at no and increasing RPM, even adjusted the AMM a little more lean. Nothing seems to affect this. I checked the fuel filler cap, fuel overflow line, sought smell inside the trunk, etc. Nothing that I can find.

It does seem that the smell is most pronounced upon starting the engine and that, with more run time, it gets less obnoxious. But I just cannot seem to find the source/cause.

So I am stumped and wondering if anyone here can help. Thanks in advance!

I was just going to post Dan's thought about rubber fuel lines as I just recently had a mystery fuel leak that turned out to be a hidden split in the fuel return line to the tank. I was checking the trans fluid level and reached down through hoses to release the dipstick and my hand came back with a drop of fluid on it, sniff, sniff, it was gas. Must have just started as there was no gas smell. I started checking hoses carefully and everything looked good, no signs of leaks or splits, no gas anywhere. Hmmm. Rubber fuel line and vacuum hoses often split near the nipples and if on the underside and not under pressure may not be evident without turning them around or pulling them off for closer inspection. I was just getting started unclamping hoses. I bent the return line hose fairly sharply out of the way to get pliers on the clamp. And there it was, a tiny split beginning in the middle of the hose out of sight underneath that would only leak if bent sharply. At least I caught that one before it started to leak in operation or sitting overnight.

Those hard plastic CIS high pressure fuel lines rarely split, but still worth a careful inspection, also the connections at the fuel filter, and as well underneath the car at the fuel pump and any accumulator that might be there. Gas vapour can drift up the firewall and be trapped under the hood. Anything to do with fuel pressure regulators is worth careful inspection. Sniffing into end if vacuum hoses is another thing to try. Spraying water at the base of the injectors as you have done usually finds any leaks there from dried injector seals, but if the seals were just starting to dry out might be a source of trace vapours under residual fuel pressure.

Plumbers sometimes check for natural gas and propane leaks with a lit match or torch, but I would never, ever do that for fuel leaks in a car. If you know someone with a gas detector yiu can borrow, that might help narrow down the area.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

I just got informed at Dave Barton's (www.240turbo.com/vac-B23Fcharcoal-tank.jpg) that my car does have a canister and now I have to check those lines. I never knew it was there lurking behind the left front bumper. Thanks

Leaky fuel injectors? Wouldn’t hurt to check your main fuel pump’s check valve and fuel lines for slow leaks and or odors.

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Will I buy another Volvo??? We'll see....

I did try hand spraying/misting some water all around/over the injectors and intake manifold parts/seals while the engine was running. I expected some change in idle if water mist was being sucked in and did not notice that. I then coated the same area a bit more heavily with water looking for bubbles, that sort of thing, and noticed nothing.

This has to be something so obvious that I am just missing it - as was the case before I found the flame trap hose popped off and open to the whole world.

Thanks

Is your fuel tank building up pressure? My 92 245 did and it turned out being a plugged vent line from the carbon canister to the filler tube vent.
Dan

I must be wrong, wrong, wrong when I say my 240 has no carbon canister. Dave Barton's valuable site shows it here (www.240turbo.com/vac-B23Fcharcoal-tank.jpg). I just didn't know about it. But I did see the two lines coming off the throttle body this morning and it goes behind the front bumper on the left side. All the canisters I have seen before were under the hood somewhere and really large and obvious. So I do have to check this out. Thanks and sorry for the poor information on my part!

I checked a bit into the evap canister thing. The two hoses from the throttle body are clearly different sized. The smaller/rear-most on the throttle body seems to be a typical vacuum connection and, when running at idle, I can feel some small vacuum there. As I am coming to understand, this actuates a purge valve of sorts on the top of the evap canister. And I presume the presence of vacuum (or at least some amount of vacuum) actuates a diaphragm inside and causes fuel (or at least fuel fumes) to get passed through the large/forward-most on the throttle body hose.

I have read of these things failing so I used a battery-powered air pump to apply pressure to the vacuum line. I wanted to see if it held as an indicator that the diaphragm in the valve was not torn. I let it get up to 10 psi on the pump's meter and it clearly held. Doing similar on the other, larger hose just stayed at zero - which I guess makes sense as this is just pushing fumes back into the tank.

I decided to run the car with and without the vacuum hose connected. This seems safe and easy. I just pulled it off the throttle body. I alternated between on and off while sniffing all around with my nose. This is very imprecise but all I got. I have to conclude that it smells more with the vacuum hose on rather than off.

I checked what I easily could both of the lines from the throttle body to the radiator area. I could not see or feel anything broken or cracked. But this is not precise either. I will have to jack the car to explore the canister side better. It is my understanding that these parts are not really available. But the next to last post here (turbobricks.com/index.php?threads/vapor-canister-valve.284229/), under the title "Volvo Vapor Canister Replacement" speaks of using some standard, Delco and NAPA parts to achieve the same effect. These are NOT inexpensive parts!

Meanwhile, I plugged the vacuum hose at the throttle body and will try driving around and see if the problem is lessened or not. IS THIS SAFE?

Thanks!

Did you carefully check the connections and bend every inch of the rubber fuel hose that connects to the return line to the tank for tiny splits. Rubber hoses in a 40 year old car are getting past their best before dates.

Pull the canister and carefully inspect the vent as well as all the hoses. The vent can get partially plugged and the charcoal can start to saturate. Here's one person's story with a 740. I can't remember if you have to crawl under the front in 240s. In 140s, I think you removed the grill for access.
https://youtu.be/zruszqtkUMw?si=_dpodCYb58-SJkVf

You said you checked the valve, but check it again once the canister is out to be sure.

Once you get the vent clear and double checked every inch of the hoses for damage or splitting, if you continue to get gas smells then the charcoal may have become saturated with heavy fuel vapours from not being able to adequately vent to atmosphere. You could try leaving the canister outdoors in the sun for a few days to see if the charcoal will gas off a bit, best with the bottom pried off such as in the video. If the gas smell doesn't go away then it may need replacement. Cheapest source is used.

Is the fuel smell strongest near the canister? If not then you may havr a minor fuel leak under the car and the vapours are drifting up and collecting under the hood.

When you've taken the gas cap off for fills, has there been a hiss?
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

That's a great video. Thanks. I have not noticed any hissing from the gas cap removal. that will likely vary by outside temperature. And here in the PNW USA it seems the hot days are now gone for this year.

I only pressure tested the evap canister's valve diaphram to see if it held air - and it does. Does not mean, I suppose, that the valve is working...

What I am not quite clear on is exactly what the valve is doing... Is it just to control the routing of fumes back to the throttle body for intake using the other, larger diameter hose? Or does it control something else? I have had no need to even realize the evap canister was there, not to mention what it does or how it works!

I will definitely try to investigate the canister in more detail.

For right now, I have plugged the vacuum line from the throttle body as that SEEMS to reduce/eliminate the smell. But it is still a bit soon to tell for sure and, perhaps, I may not be able to tell until next summer when the air temps finally increase again around here :-)

Thanks to all!

Thanks. Pulling off the gas cap I hear/feel nothing. I smell no gas in the trunk. I am not sure that my '83 even has a carbon canister. I cannot seem to find a part for it listed.

I just removed/inspected the plugs and O2 sensor. All seem fine. Nothing wet, fouled, or highly carbonized. Hmmmm.

Hi,

I’m guessing here as well since it’s a 1983. I have a 1984 LH so the guess is you have a very early LH.

These early ones went through some experimental designs with the fuel pressure regulator and with in that the diaphragms leaked more frequently.

With that notion, out in the air👃🏻 be suspicious of the FPR.
It happens that the gasoline weeping lays in the intake manifold filling up every void of the incoming breathing pipes and the air cleaner.

The line maybe fairly full but not pressurized.
When it gets worse, the longer it will take to crank the car to replace fuel.
This usually causes the hard or long cranking issue and running rough for a few seconds.
Check the vacuum line for a heavy gasoline smell as it use that path to dump through.

The smell varies after the engine gets hot so the starting it cold lends itself to be more pronounced around any still air and then, the engine fan will whisk it about.
The tailpipe shouldn’t be smelling of incomplete burning or fumes after all the intake manifold gets mixed with incoming air.
What you might be getting back there is from the engine bay routing it under the car.

Have you noticed any lack acceleration or stumbling at low revolutions before dropping a gear.
If I’m right it will the last move for the FPR will be able to show off its “talents” in not working correctly.
It is subtle and down right sneaky but that’s the different nature of its failure rate.


Phil

Oh and no, the engine is running smooth and great. No stumbling, sputtering, back fires, or anything like that. Strange! Thanks

Thanks Phil. I understand that the FPR is a "usual suspect" and I am frankly amazed I have never had to replace mine. I am 99.9% sure it is not the culprit here. With engine running, I removed the vacuum hose from the FPR. No sign/smell of fuel and idle increased a bit. I could feel suction on the end of the hose from the manifold. So hose is not plugged. When the hose was re-installed, idle decreased a bit.

Hi,

Ok when you say you removed the vacuum line from the FPR thus means you do have a LH vehicle.
You put out that this was a California car so I’m thinking it must have a fuel vapor canister.
My 1984 does one and I think my 1978 GT also has one.
I have owned the ‘78 K jet since 8,000 miles but with having five other 240s to spread my maintenance time across, it’s not a big item to log into my brain anymore.
I’m out of town tonight but I will look tomorrow afternoon to look up under the left or drivers side of the front bumper.
On all my other LH’s it’s in the same place.
It’s Hard to believe your car didn’t get one.

You might want to look for lines and missing things.
How long have you had the car?
Most of the cars have only had one or two other owners and Luckily unmolested at that. Stock has its attributes.

The ‘78 Lambda Sond O2 sensor was the newest thing along with multi injectors. It was a single wire sensor. No heater wire until 1985-6. The sensors doubled in price for that gimmick to fool the establishment some more.
I’m pretty sure the fuel vapor controls were mandated in California for that year.
My 1974 FORD F100 had some EVAP canisters mounted down real low to the right of the transmission. Those promptly rusted into pieces and filled with water.
My 1987 Chevy motor home has them and an air pump.
The air pumps and the EGR valve under the carburetor was a political joke played from both sides. The Solution to pollution IS dilution.
Burn what doesn’t have time to burn, later, in a catalytic converter, didn’t help efficiency either.
The whole emissions “retarding the spark” package was what helped me to never buy another FORD or American vehicles.
I put sights on the EUROPEAN side and hit on Volvos
The Japanese were already turning heads but it took time for “qualities” to sort things out.
We learned the rest of the story in chapters with each passing decade.

The same playbook is winding down on or up on the idea of “battery” powered Electric vehicles.
IMHO this stupidity is going ton hit the global consumers squarely between the eyes, of which, will blindly be pushing consumers into another pollution problem.

Hydrogen fuel cells and capacitor building technologies area looking a lot better to me.
Remember imagination built the “Back to the Future” movie a “Flux capacitor.” 😵‍💫

The UNIVERSE or COSMOS is made of mixes of a foundational carbon structures.
Hydrogen atoms are only one type of energy.
Others area scattered in different forms around us.
I’m sure there are more than nine forms that scientists are using today.
We are only interested enough to exploit the “easiest” ones first like those from hydrocarbons.
Uranium and all its parts, were surprisingly tantalizing to say the least.

The quest for “Energy” will drive mankind's desires to find more of them forever.
Star Trek as entertainment or the space race bug has had that underlying in itself as a reason to even exist.

Maybe not a FPR at this time but it will have a failure, as it is man made and time is very patient. 😬

Phil

I'm not familiar with the 83 set up, hope you figure it out!
Dan

Well, I have confirmed that my 1983 242 from Calif does NOT have a carbon canister. At least that is eliminated :-)

My daughters 92 had a slight fuel leak at fuel rail and the rubber line from the fuel pump.

I am guessing you have a Kjet mechanical fuel injection, if so there are a lot of fuel lines and connections that could leak.

Hope you find it, keep looking.
Dan