Next steps to eliminate gasoline smell?

barzee · 06-05-2014, 05:37 PM

I am tired of the gasoline smell in the cab of my 1987 Porsche 924S. The smell is most strong when driving with the roof up or the windows open. In other words when there is low pressure in the cab, the fumes are being sucked into the cab.

I have read multiple posts at this forum and others about this smell. I replaced the gas cap as some suggested, but that made no difference. Tonight I removed the cover over the fuel level sender unit and didn't notice fumes. I removed the interior panel that covers the filler neck, and the smell of fumes was strong. It appears there may be some fuel residue near the front of the panel (left side of attached picture). I'm not sure what to look for or what to replace. Is it a good idea to replace the filler neck and vent hoses? What about the valve like things? Which of these can I replace without dropping the tank?

If I have to drop the tank, I understand I have to drop the transaxle first. I can't find directions for dropping the transaxle and tank. Do you know of a post where I can find directions?

Bukowski · 06-06-2014, 04:24 AM

Tracing fuel odor by nose is a nebulous activity, however:

I can report for my late MY ('87) (and perhaps in a previous thread) that at this precise location, where the hose connects to the tank, the body sheet metal edge, having sharp droplets of cured paint on it, managed to press the hoses that go underneath enough to look/smell leaky. The short one going to the expansion tank too.

If you want a new filler neck hose - the largest one - I got mine at fuel filler neck supply (google those words to find it) because it is NLA even from the local Porsche shop...

HTH

John_AZ · 06-06-2014, 05:12 AM

The tank on a 924S will crack on the top center.

Gas fumes? Tank leaks? Read this.

Usually a radiator shop can weld for $100 to $150 when removed.

There is no other fix for this. I have tried a couple of tank sealers but the body "flex" will reopen the seal.

Replace the vapor hoses on top of the tank.

Make sure when you have the tank welded, they understand the vapor hose and plastic collection tube need to lay in the same groove as the weld. If they put a crappy thick patch over the crack the tank will not fit.

Clarks-Garage has information on removing the tank. It can be done with out special tools but easier with a transmission floor jack.

Do not strip the 2 coupler bolts to the torque tube!!

J_AZ

FLYGEEZER · 06-06-2014, 09:54 AM

Don't fill the tank. Stop at 3/4 full. I've had my 944 for a long time and I know the tank's gotta be cracked as J_AZ mentioned, but I don't wanna look, so .....for now I just don't fill the thing up. Fumes gone.........maybe to somewhere else but not in the cabin.

barzee · 06-06-2014, 09:35 PM

John_AZ, thanks for the pointers, especially Clark's Garage. Why did you mention the bolts on the torque tube? Are they "cheese head" bolts? I think the bolts attaching the CV joints to the transmission are also cheese head. Or is there something else about the torque tube bolts that I should understand before I begin this repair?

Bukowski, I found this web site: Fuel Filler Necks & Gas Tank Pipes | Filler Neck Supply Co. Is that where you purchased a filler neck? At that website they don't list Porsche as one of the makes that they have parts for. Did you simply remove the neck, measure its diameter and length, and order hose from fillernecksupply.com? Also, when I measure a hose do I measure the inner or outer diameter?

Flygeezer, I never fill the tank all the way up, and the smells are still too much for me.

John_AZ · 06-07-2014, 02:37 PM

Quote:

Originally Posted by barzee

John_AZ, thanks for the pointers, especially Clark's Garage. Why did you mention the bolts on the torque tube? Are they "cheese head" bolts? I think the bolts attaching the CV joints to the transmission are also cheese head. Or is there something else about the torque tube bolts that I should understand before I begin this repair?

The transaxle to torque tube shaft "coupler" uses 2 8MM 6-sided hex metric bolts.
Depending on your climate and condition of car these may be corroded, pinched, or previously damaged.
It also is not a straight line up with a socket due to the front transaxle nose sheild.
Both bolts must be completely removed from coupler

If you are not careful you could damage the head and the work to remove a damaged bolt is painful.

Wake up all bolts per Clarks Garage-
Waking Up Bolts

Use a decent set of hex and Triple Square/cheesehead/XZN fot the drive shaft bolts. A cheap set like Lisle or KMart will fail.

J_AZ

Bukowski · 06-08-2014, 05:24 AM

One undocumented thing I discovered when dropping the tranny was a silver-colored grease on both drive shaft and tranny input shafts, apparently anti-seize.

As a novice, I recommend bagging these areas, as dust/debris can accumulate.

When I have a good idea what the grease is, I might add some, but...

Bukowski · 06-08-2014, 05:40 AM

Oh the neck - yes measure and choose.

In practice I had to order three to be certain of the fit.

I can give a number when I get around to it...

Bukowski · 06-10-2014, 09:47 AM

Ok, looks like 1-7/8" ID is the one that is closest. I didn't check their site, but it sounds right.

I also got two of 944 201 217 00, little gaskets and they fit well.

Bukowski · 07-06-2014, 02:51 PM

I just discovered : the OD of the filler neck I got is too big for the old original hose clamp. The OD of the new hose is about 65mm, the old one about 55mm.

sorry about that.

pfarah · pfarah's Garage

This will be a job for the upcoming winter. My goal is to have a rebuilt torque tube and tank by then; I have a spare of each...

arominus · 07-09-2014, 09:03 PM

Drop the tank, look for a crack in the gas tank and if not cracked, replace every fuel hose back there. That was the only way i was able to get rid of the smell in my 924S.

I did that and it got hit a few months later, it was nice while it lasted. I sold the crack free tank and lines long ago at least.

Bukowski · 06:24 AM

Update :

Gemi 40-60 hose clamp appears to fit the 1-7/8" ID hose I got from fillernecksupply.... except when it doesn't! Argh - try a step up. I used something from Home Depot.

here's a 50-70 mm on Pelican:

http://www.pelicanparts.com/cgi-bin/ksearch/PEL_search_2014.cgi?command=show_part_page&please_wait=N&SUPERCAT_FLAG=Y&make=POR&model=944M&section=WATRAD&page=3&bookmark=7&part_number=HC50709-M130

If you go to McMaster, be careful - the bolt clamp I got seems way too heavy - as in weight tugging on the hose for this. The band width - about 3/4" - is too much because the bolt gets placed in a cramped location on the tank so it can't be tightened. If there is something on McMaster, it would have to be a band width like a typical hose clamp.

HTH

jhowell371 · jhowell371's Garage

Try using a vented gas cap to prevent pressure build up in the tank. Been there done that.

barzee · 10:31 AM

I removed the transmission from my 1987 924S today. Thanks to everyone for the advice! I removed the fuel pump and filter and the tank straps as the Haynes manual said. I removed the cover over the filler neck in the trunk, disconnected all the hoses, and even cut off the filler neck hose because I was going to replace it anyway. I disconnected the fuel level sender wires. In short I removed everything that I can find that is holding the tank in, and I can wiggle the tank, but I can't seem to remove it. The Haynes manual says only, "Lower the tank downward and to the rear," which is what I'm trying to do.

What is the trick to removing the tank? A pry bar? Where?

Bukowski · 09-05-2014, 02:25 AM

If it is like a 944, and plastic like mine?...then there will be some good tugging involved, but not sweat-inducing. and I recommend protecting the tank from the mounts it is close too... You removed the sender wire, two bolts..?

I wouldn't cut hose... also, I managed to get my filler neck hose in but there's little room left over. What filler hose did you get?

Also warning, I am saying this based on a late NA 944.

barzee · 09-05-2014, 10:24 AM

No, it is a steel tank, and I think it has small cracks on the top of it as many other 924 owners have reported. If the cracks are there, they are probably the biggest reason for the fuel smell.

I cut only the fuel filler neck because I figured I was going to replace it anyway. Why did you say that you wouldn't cut the hoses? What is wrong with cutting them if I'm going to replace them?

barzee · 09-05-2014, 01:20 PM

It required a lot of pulling and some careful prying with a pry bar, but I finally got the steel tank out of my 1987 924S. I have read Neil-Colorado's thread about gasoline fumes many times, so I fully expected to see cracks at the top of the tank where Neil found them. When I examined the top of my tank, I almost couldn't believe my eyes. One of the two previous owners had a "professional" stereo shop install a fancy Sony amplifier in the trunk. The installer put two screws through the trunk bottom and into the gasoline tank (see the pictures below). I'm still having trouble believing the stupidity and am waffling between utter disgust and laughing out loud.

I don't see any evidence of the cracks that Neil found on lots of gas tanks (see the pics). So what do you suggest that I do to plug the two screw holes?

Bukowski · 09-05-2014, 03:41 PM

Congrats barzee - I'm rather speechless - the costs of knowledge I suppose?

barzee · 10-14-2014, 02:15 AM

For my 1987 924S I found that 1 7/8" was the closest size for the fuel filler neck hose. I bought one from www.fillernecksupply.com that did not work. The only hose that fillernecksupply has in 1 7/8" is like a rock. It simply will not expand to go over the bead around the fuel tank opening. I'm not kidding about it being as hard as a rock. It is crazy tough. I'm not sure what it could actually be used for.

I bought another fuel filler neck hose from hwww.ebuggies.com/, and it was actually flexible. However, I still had to heat it in my oven on its lowest setting so that the rubber was soft enough to be able to install it.