Author Topic: This is ugly... (fuel leak) (Read 3758 times)

nigel · « **on:** May 10, 2012, 06:03:36 PM »

I've developed a fuel leak that I thought was from a fuel pump hose. After lifting the lid on the pump, putting in a new o-ring, and tightening hose clamps, I found that most of it was spattering from somewhere just out of reach under the floorpan. So I cut a little piece out. The leak moved. Cut a little more, moves a little more. A big, frustrated cut later and what I have is this: http://www.flickr.com/photos/49048493@N06/7173361530/ http://www.flickr.com/photos/49048493@N06/7173361530/
Most of the fuel comes from the piece of floor pan that's bent up. It sprays out in a fine mist from in between the chipped edge of the tan underbody coating and the metal. I guess the leak is actually somewhere else, and it's worked it's way under the coating.
So my question is: where could the source possibly be? It pressurizes real quick and starts leaking as soon as the pump turns on.
Also, I don't have access to anything more than some makeshift ramps, so I can't lift the car very high, and I definitely don't have the means to drop the tank.

danlolasdad · « **Reply #1 on:** May 10, 2012, 06:18:49 PM »

the steel pipes on the left of your pics are braised to the tank it looks to me like they have rusted through you could by pass them this pic will help you visualise better

http://i100.photobucket.com/albums/m17/vlad-e30m3/misc/fuel-tank.jpg

DesktopDave · « **Reply #2 on:** May 10, 2012, 06:25:56 PM »

Id' suggest getting a few feet of 8x13 high pressure injection fuel line and an inline fitting. Splice the hose onto the good part & run it under the car to where that line goes.

Your tank should have four lines - fuel going to the motor, fuel return, a line to the charcoal canister up front and a breather hose to the expansion tank. I don't recall which is which, however.

Here's the (e30) fuel system diagram.
Here's what the e30 tank ventilation system looks like.

I know what you mean about dropping the tank as well. Even though I have the means, and the parts, I still keep putting it off. A fuel leak is a pretty high-priority problem however. I'd advise taking the car to your mechanic for this one. There's no use risking yourself, passengers & car over saving a few hundred bucks.

keflaman · « **Reply #3 on:** May 10, 2012, 07:24:37 PM »

That has got to be the most invasive troubleshooting I have ever seen :eek: but, yeah, even with a four-post lift in my garage swapping gas tanks was a b!tch. Your tank looks very similar to what mine did and that was just a hint of problems I ran into dropping the tank. I'd suggest you inspect and tentively start planning for new (or serviceable used) hard fuel lines, subframe bushings, parking brake cables and brake lines.

P5100036 by ianmccann86, on Flickr

bmwman91 · « **Reply #4 on:** May 10, 2012, 07:45:23 PM »

I think that removal of the gas tank is more or less mandatory at this point. Gasoline is no joke and injures & kills people every year during DIY maintenance projects. The proper way to fix this is to drop the tank (which is probably where the leak/damage is anyway) and replace it. It isn't worth trying to hodgepodge something together because the risk of fire is high.

At the very least, you'll need the tank out to weld that "inspection port" back together.

ak96ss · « **Reply #5 on:** May 10, 2012, 09:02:14 PM »

First post in ages - I have to say it isn't *that* hard to drop the tank, although there are lots of ancillary tasks involved - exhaust, driveshaft, etc. I did it in my sloped driveway on jackstands, so it can be done.

I'd agree, at this point you need to take it out.

nigel · « **Reply #6 on:** May 11, 2012, 09:14:30 AM »

Yeah, I know the best thing would be to drop the tank, and I know that I need subframe bushings as well, but honestly, as much as I love this car, I only paid $600 for it, and there is some pretty heavy duty rust (it came from upstate New York) and many other problems that I just can't afford to fix. Also, it's my DD. I have a bike I can ride for a few days, but it's been rainy here lately, and that's not a great option.

I figured those hard rails across the top of the tank might be the problem, but it looks like it's coming from the front side of the tank where that other hard line (the one in my pic that's on top of all the others, and joins to a piece of plastic line on the right) goes. Is it part #11 in the RealOEM diagram? If it is, then it shouldn't be pressurized and wouldn't leak like that, right?

Thanks for all the help guys!

DesktopDave · « **Reply #7 on:** May 11, 2012, 10:54:57 AM »

I'm not sure how the hoses are routed, to tell you the truth. Two should have pressurized fuel...two should carry air. I'm figuring the one you have leaking is running from the pump to the filter. Replacing that line with the tank in place is ticklish but possible.

Would it help to have pics of a tank? I can pull mine out of the box and show you what it should look like...those RealOEM diagrams aren't the best.

Regardless, I'm glad you're on top of this. If the rust is too far gone it's not worth replacing the tank. IMHO just patch it & run it 'till it dies. If you really love the car just buy another e30 with a blown M42 & swap what's left once this car is done. As much as I love these little cars, road salt is a major enemy and once the rust has gotten hold...old cars cannot be economically repaired.

mr ilia · « **Reply #8 on:** May 24, 2012, 09:38:36 PM »

If you are leaking from the metal hose then just jb weld it for now or use a special gas tank clay from auto parts store. See if it helps. It ia a band ait, but it will give you tie to think through.
To be honest, if jb weld fixes it, then you should be permanently good. Jb weld is a type of mother fucker that never gives up. I had it fixed so many things and it is holding strong. Exampkes are: engine block in my acura, a/c condencer leak in a e30 and a slash at the bottom of a gas tank in my old tempo.