Intermittent Gasoline Smell in Coach

[B and L]

Hi.I purchased my lightly used 2005 24RB Born Free Class C in November of 2018. It is on a Ford E450, V10 Chasis.

I took it on its first two excursions from NC to FL in January. During that time it had a very strong gasoline odor that would come intermittently. This is a raw gas smell, not exhaust, and not LP gas. It was so strong the first time it happened that I got a hotel that night. I scheduled a mobile RV mechanic for the next day. Coincidentally my LP gas detector went bad that same day so we ended up focusing on that and the gasoline smell didn't appear that day. I went on my way and the next day it didn't happen at all, but I think it happened one more time on that trip. That was a short one week trip. Then mid January I was able to go back to Florida for two weeks. It happened a couple more times on that trip. When it happens the smell is most concentrated by the rear door area and gets the most trapped under the cabinet under the stove and the kitchen sink so that even after the fumes have cleared out of the rest of the coach you can still get a whiff under the cabinet later.

It has only occurred after I have been driving a while, not while being parked. And no wet spots have showed up on the ground under the rig. It hasn't happened on a full tank, but has happened anywhere from two-thirds or a tank down to a quarter tank (I don't go less than that). It has happened when it has been really cold out (right at freezing) and warm out (70s). These are just observations. It could happen on a full tank...it just hasn't yet.

I dropped it off at a Ford dealership that has the capacity for mortorhomes about three weeks ago. They finally were able to get to it last week and have not been able to find a leak. They have parked it up hill and downhill over night. The said they don't think it would be the charcoal canister or EVAP System (and gave me a reason that I don't understand). They said it is not the line to the generator. I went there yesterday and picked it up and drove it for four hours to see if I could get the fumes to occur but it didn't.

When it happens it is so strong that I have to roll down the windows or get out of the coach. It is not like, "oh maybe I smell gas", but very very strong, especially toward the rear of the rig.

The guy I bought it from in November (who was the 2nd owner) seems to be a very honest guy. He had it for only 8 months and then ran out of money so he sold it, but he swears he never had this happen to him. They just lived in it locally while they were working on a house though and didn't travel in it other than when he drove it from Oregon to SC after purchase. It had 23,500 mile on it when I bought it and I have it up to 27 and something now.

Does anyone have any suggestions as to what they should check or what this could be? I'm going to be moving into it full time in less than two months and don't want this to occur while on the road when it can take so long to get into a shop.

[LJowdy]

Being a Class C, I would suspect that the gas tank is towards the rear of the frame????
If so, I'd crawl under the coach and look for vent tubes or some form of venting the gas tank that may have come loose. In addition, I'd check the hose that leads from the gas filler (probably on the drivers side) to the gas tank. In fact, I'd check all the hoses to see if they have cracks or are brittle. If so, I'd replace all of them. It is possible for a cracked hose to emit smell and no liquid, especially when the tank is partially empty (or full depending on how you look at it)

[Mojim]

Originally Posted by LJowdy

Being a Class C, I would suspect that the gas tank is towards the rear of the frame????
If so, I'd crawl under the coach and look for vent tubes or some form of venting the gas tank that may have come loose. In addition, I'd check the hose that leads from the gas filler (probably on the drivers side) to the gas tank. In fact, I'd check all the hoses to see if they have cracks or are brittle. If so, I'd replace all of them. It is possible for a cracked hose to emit smell and no liquid, especially when the tank is partially empty (or full depending on how you look at it)

I agree I think one of the hoses..

[avfordguy]

Ok stark asking questions to the Ford dealer. Did the tech check the OBDII monitor, did it pass the on board readiness test? Did it complete the monitor yest when it was cleared ( takes about 10 miles at specific conditions). If it passed then fuel tank,filler neck,and all storage devices are tight. Then I would look from the fuel tank forward and look at every inch of high pressure fuel lines to the engine then check the return line from engine back to the fuel tank. I will see signs of intermittent leaks by discoloration.

[Bahamaniac]

Also the fuel filter is on the driver's side. You might want to change it also.

[B and L]

Originally Posted by LJowdy

Being a Class C, I would suspect that the gas tank is towards the rear of the frame????
If so, I'd crawl under the coach and look for vent tubes or some form of venting the gas tank that may have come loose. In addition, I'd check the hose that leads from the gas filler (probably on the drivers side) to the gas tank. In fact, I'd check all the hoses to see if they have cracks or are brittle. If so, I'd replace all of them. It is possible for a cracked hose to emit smell and no liquid, especially when the tank is partially empty (or full depending on how you look at it)

That is correct...the gas tank is near the rear of the frame. I read your remarks directly to the service writer at Ford and I hope he can get someone there to move forward with following through on this for diagnostics. Thank you!

[B and L]

Originally Posted by avfordguy

Ok stark asking questions to the Ford dealer. Did the tech check the OBDII monitor, did it pass the on board readiness test? Did it complete the monitor yest when it was cleared ( takes about 10 miles at specific conditions). If it passed then fuel tank,filler neck,and all storage devices are tight. Then I would look from the fuel tank forward and look at every inch of high pressure fuel lines to the engine then check the return line from engine back to the fuel tank. I will see signs of intermittent leaks by discoloration.

I read all of this through to the service write and he tells me they did this except for possibly the part about the monitor test at 10 miles. I'm not sure I really understood what you meant, so I may have not explained that properly but he told me it isn't necessary to do that. And he went on about why not (all of which I don't understand).

He says they are going to perform smoke test now to see if they can find anything.

Thank you for your insight!

[B and L]

I just heard back from the dealership and they ran a smoke test on it. They said when they walked into the shop after leaving the smoker on the rig for a few hours that the smell of gasoline was so strong they couldn't even be in the shop (same as in the RV). They traced the leak to the gas cap. I asked why the diagnostics didn't pick up on that and he said that all of those components are on my vehicle, but since they are sold to the RV manufacturer as incomplete vehicles that they don't necessarily activate everything. Very strange to me. But anyway, they got a new gas cap on there and are now running another smoke test to make sure the new gas cap solves the issue. I'll update this post once that is complete. I'm so happy that it might be this easy! Fingers crossed!

[Waiter21]

Remove the gas cap next time you drive it and see if you still get the gas smell event.

THOUGHTS:

Is the odor (leak) coming from the fuel supply /return lines. With the engine running, the fuel supply to the fuel injectors will be under pressure from the fuel pump. Possible source of leak could be o-rings on the quick disconnects at the fuel filter and also the engine. Also possible o-ring on any of the fuel injectors.

You could sprinkle talk powder on all these connectors. if there is a tiny fuel seepage, it should show up in the talk powder.

With the gas cap removed, there will be no pressure in the gas tank. This would eliminate the EVAP return and fuel tank vent (EVAP RETURN) plumbing.


OPS Looks like you may have found the problem.....

[Podivin]

Glad that they found it!

What's a "smoke test" in this instance, what did they actually do?

[JoeSR]

https://www.autologicgso.com/smoke-leak-test/

[B and L]

Originally Posted by Podivin

Glad that they found it!

What's a "smoke test" in this instance, what did they actually do?

I know they said that they had to hook it up in an unusual way. Why they had to do that, I can't remember exactly. But the link that @JoeSR put in the post is what they did. And when they ran the smoke test again after installing the new gas cap, there were no smoke leaks or gas smells, so apparently it worked and in this case ended up being a great diagnostic tool when they couldn't find any visual leaks and no codes were coming up.

[B and L]

Originally Posted by Waiter21

Remove the gas cap next time you drive it and see if you still get the gas smell event.

THOUGHTS:

Is the odor (leak) coming from the fuel supply /return lines. With the engine running, the fuel supply to the fuel injectors will be under pressure from the fuel pump. Possible source of leak could be o-rings on the quick disconnects at the fuel filter and also the engine. Also possible o-ring on any of the fuel injectors.

You could sprinkle talk powder on all these connectors. if there is a tiny fuel seepage, it should show up in the talk powder.

With the gas cap removed, there will be no pressure in the gas tank. This would eliminate the EVAP return and fuel tank vent (EVAP RETURN) plumbing.


OPS Looks like you may have found the problem.....

Thank you for your suggestions. They just called and they say they have confirmed it was the gas cap, so great instincts on your part! They had already visually inspected everything and couldn't find any leaks or signs of seepage, so the smoke test was the winning diagnostic tool on this one.

[B and L]

So, just to sum things up in case anyone comes across this post because they have a gas/fume odor problem. It ended up being a bad gas cap. For some reason, and the Ford dealership says they don't know why, but the bad gas cap will not trip a code or throw a code or whatever you call it, on this vehicle. That part of the diagnostics are not active. The Ford being sold to the RV builder as an incomplete vehicle was the only thing they could come up with on that part, but they said there is actually nothing wrong with my sensor, it just isn't set up to detect that. After visually inspecting everything and not being able to find any visual signs of leaking gas, they opted to hook it up to a smoke machine. They were then able to see smoke seeping out at the gas cap and nowhere else in the system. The smoke test also triggered the odor so they were able to smell the very strong smell that I had been telling them, but that would had not presented itself up to that point while at the service center. After replacing the old gas cap with a new one they ran the smoke test again and did not see any leaks or smell any gas. This ended up costing $411 in case anyone is interested. Some may think that is high, but I believe they really spent a lot of time trying to trace the problem, and in the long run, the peace of mind from it being solved and knowing I won't likely blow myself up now when I light the stove is worth it! Thank you for all of your insight!