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1999 BMW 528i
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Discussion Starter · #1 ·
Got a new quirk to a recently acquired '99 528i.
Had it for maybe 6 months or so but just recently I've got a strong gas smell inside the car.

This can be aired out with the windows down and a short drive, but after being parked and closed up it'll be back.

I notice this happened right after a full tank of gas was done.

I see older threads talking about possibly some fuel sender and something else under the rear seat.

I was hoping for some insight, maybe some visuals if possible. I'll be turning to YouTube here shortly to see what I can see.

Thanks in advance!
 

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That may be caused by the vapor recovery system hoses. Best check it out before there's a flash on the horizon.

There may also be a defective fuel pump hose. The fuel sender itself is inside the tank, and will not cause vapor leakage.

Another possibility is the hose between the filler pipe and the fuel tank.

I hope you don't keep jacking the gas pump nozzle after it shuts off by itself.
 

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Gaskets for the fuel pump assembly and fuel sending unit, possibly deteriorated or loose.

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Have you pulled the rear seat bottom and removed the 2 access covers to see if that’s where the leak is?
 
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Very very difficult to see but on the plastic fuel tank lids you might have a hairline crack, fill with some glue.
 

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1999 BMW 528i
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Discussion Starter · #6 ·
That may be caused by the vapor recovery system hoses. Best check it out before there's a flash on the horizon.

There may also be a defective fuel pump hose. The fuel sender itself is inside the tank, and will not cause vapor leakage.

Another possibility is the hose between the filler pipe and the fuel tank.

I hope you don't keep jacking the gas pump nozzle after it shuts off by itself.
I'll look into the hose, potentially just replace it for the sake of it being new. No I've got no issue with the nozzle at the pump. If it says it's done I'm not one to argue!
 

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1999 BMW 528i
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Discussion Starter · #7 ·
Have you pulled the rear seat bottom and removed the 2 access covers to see if that’s where the leak is?
This is my plan to start. Afraid it'll have to wait until tomorrow evening. Gas mileage is fine, no puddles on the floor, just odor so far.
I'm familiar with the rear seats as I replaced the rear deck speakers last month so that'll be a easy check hopefully. I'll report back!
 

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1999 BMW 528i
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Discussion Starter · #8 ·
Very very difficult to see but on the plastic fuel tank lids you might have a hairline crack, fill with some glue.
Hmm okay I'll check that out too. Luckily I work at a shop (sales, not a tech) so putting the car in the air isn't out of the question either.
 

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1999 BMW 528i
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Discussion Starter · #9 ·
Well, just a small update, pulled it into the shop and got the rear bench seat up. Looking under the access plugs, on the passenger side I've got a mouse nest, but it appears dry within.

The more concerning thing is that under the black rubber mat there's another blacking lining that is soaked in fuel. Going to focus my attention on cleaning up the nest and taking the black barrier up so I can get a better view on what's up tonight.
Crazy how fast the priorities change!
 

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Well, that is the first thing to do, remove stuff so you can get access to possible causes...
 

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Discussion Starter · #11 ·
While not fixed yet, I did find the issue.
Long story short, a mouse chewed a hole into my fuel sender.

I peeled back the rubber mat and there was a clear fuel stain on the passenger side. I took the access plugs off, and then the plate held down by three Phillip head screws.

Vacuuming up the mouse trash, everything was dry. So I went to a nearby gas station without putting anything back together. Sure enough, once it gets going I look through the window and see a stream of fuel shooting out of the tip of a plastic piece on top the sender.

Stop fueling and wipe it down I feel around it and take a closer look, and there's teeth marks around it.

So one of the techs at the shop boogered on some epoxy but I'm going to be pulling the trigger on a new one here tomorrow and replace it myself.

Thanks for the advice guys!
Tire Automotive tire Tread Vehicle brake Alloy wheel
 
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