Fuel Leak!

[RainMoore]

Hi all,

    I've been posting here recently about my 74 2002 Automatic and it's electrical system. Today I replaced the condenser and points, and voila I had spark!

 

Unfortunately, I still couldn't get the engine to turn over. Sprayed some starter fluid down the carb and for the first time heard the engine turn over. Its petered out immediately, and after three more tries I went to inspect the engine and found that the mechanical fuel pump is leaking gas onto the intake manifold...yikes.

 

Looking carefully I realized that the fuel filter is not filled with gas. Only a half oz or so sits at the bottom. I don't know if this is normal or not.

 

Is this a fix I could do myself? I'm assuming it's a gasket in the pump itself.

 

Thanks!

[Son of Marty]

If you mean it leaking from the pump body onto the intake manifold, you'll need to replace the pump, the style in your picture is a sealed unit and there's no repairing it.

Edited April 16, 2021 by Son of Marty

['76mintgrün'02]

The inlet nipple on that pump is 8mm and the outlet is 6mm (which is typical).

 

Are you sure the leak is not coming from the hose clamped on the outlet side?  It looks like an 8mm hose on a 6mm nipple that's been squished extra hard by the clamp... and prone to leaking.

 

Tom

['76mintgrün'02]

Have you inspected the fuel lines coming off of the tank, in the trunk, under the floor board, on the right hand side?

 

The nipple that comes off of the fuel sender in the tank is supposed to have a plastic sleeve on it, to size the 6mm nipple up to 8mm.  That sleeve has often gone missing, or has cracked and can allow air to get sucked into the line, or fuel to dribble out of the line.  If the hoses are the cloth covered kind, they may be original and should be replaced.  Any leaks back there will allow the pump to suck air and can lead to fuel starvation problems.

 

If you are missing that sleeve on the sender nipple, you can cut a piece off of the end of the plastic fuel line that runs in through the cabin and use that.  I used a piece of that on the pump outlet nipple as well, so I could use 8mm fuel line from there to the carburetor.

 

 

It is common for the fuel filter to have some air inside.  

 

Which carburetor do you have?

 

Tom

[RainMoore]

Thanks, I hadn't checked that carefully. I think the hoses have been replaced at some point (they're all rubber and don't look all that old).

If I were to replace them what would I want? 8mm? Cloth braided or no? Might as well while I'm in there.

 

As for the filter, there's like 90% air. Someone here said some, but it seems like a lot...

 

If I do need to replace it, the pumps I've found online has an 8mm inlet and 7mm outlet. Does this matter if I can properly attach all hoses in some way?

 

Its Weber 32/36 (I think). Vacuum advance distributor. Haven't rebuilt it, yet. Its pretty gnarled in there.

Need to clean it better, just learned where the model is printed on the base so it may be a 36/36.

Its strangely got a manual choke with no choke cable attached and no choke in the cabin, so I'm guessing it never had one. The previous owner instructed me to tap the accelerator when starting...

[Son of Marty]

I had assumed (a bad thing when trouble shooting) that the pump was leaking from the flange where the two haves are pressed together, in this case the pump is beyond practical repair, but Tom looks to be right with the hose leak in the picture you can see where the gas has cleaned off the grim from there down.

['76mintgrün'02]

I think we're better off using modern fuel hose that doesn't have the cloth cover.  The cloth stuff is cool looking, but it's harder to monitor the condition of the rubber and I've read that it can be hard to find quality stuff that tolerates the ethanol laced fuel.  I go out of my way to use the ethanol free fuel and can notice a difference in how my car runs.  

 

46 minutes ago, RainMoore said:

Its Weber 32/36 (I think). Vacuum advance distributor.

 

I like my 32-36.  If you do a site search for the c.d. jetting prescription, it seems to work well for a lot of people.  That's the setup I used in mine, aside from adding one larger air corrector jet on the primary side.

 

Your distributor is a vacuum RETARD, not advance.  I'd recommend unplugging the vacuum line that feeds your distributor and capping off the nipple it was attached to (on the carb base, or on the manifold).  The vacuum retard feature was controlled with electric vacuum switches as part of the emissions system and you're better off without it connected.

 

Depending on where you live and the time of year/temperature, you might be okay without a choke.  You do need to make sure the choke flaps stay in the open position though and are not able to flop around.  Ideally, I'd look into connecting the choke back up.

Tom

[RainMoore]

23 minutes ago, '76mintgrün'02 said:

I like my 32-36.  If you do a site search for the c.d. jetting prescription, it seems to work well for a lot of people.  That's the setup I used in mine, aside from adding one larger air corrector jet on the primary side.

 

I should say that I live at about 7,500 feet in a dry mountain town -- so no rust but rubber doesn't stand the test of time. The carb may be tuned and jetted appropriately already, but from what I understand it'll run best with a larger air jet, no?

Don't know much about carbs, yet.

 

1 hour ago, '76mintgrün'02 said:

Have you inspected the fuel lines coming off of the tank, in the trunk, under the floor board, on the right hand side

 

To the best of my knowledge the fuel lines look solid, tho I'm a little confused about the two lines. One is the main fuel line, one is a vapor tube (its blue) and the third I'm not sure about. I think you're right about the connection to the pump itself, thanks for spotting that in my very unhelpful picture.

I should say that the rubber neck to the tank filler is cracked badly. I've used permatex to seal it back up. Don't know if that could be an issue or not.

 

26 minutes ago, '76mintgrün'02 said:

I think we're better off using modern fuel hose that doesn't have the cloth cover. 

 

Do most auto parts shops cary these that are quality, or would I need to order them online?

[Hans]

That hose caught my eye too. Start there.

['76mintgrün'02]

17 minutes ago, RainMoore said:

Do most auto parts shops cary these that are quality, or would I need to order them online?

 

I think you'll be fine with auto-part-store hose.  Don't buy the fuel injection stuff that's stiff.  Get the soft stuff that the hoses get a grip on.  8mm works for all of it, if you use the plastic sleeve on the two small nipples, or you can run 6mm from the pump to a fuel filter and size up from there to the carb.  Don't try to squish 8mm down tight onto the 6mm nipple.

 

Being at such high altitude, your carb will require different jetting than mine.  I'm at about sea level here and jetting needs tweaking once over 3000 feet, so I've read.  That's about as much as I know though.

 

Photos are helpful.  The hoses in the trunk vary a bit, but there's a plastic fuel line that runs through the cabin that feeds the fuel pump and another steel line that runs under the car on the driver's side that is/was the fuel return line.  That one is often capped off when the fuel bypass valve is removed, along with the emissions stuff.  The metal line turns to rubber hose down under the battery tray.  That can become a fuel leak, if it is not capped off well.  Some people suggest disconnecting it back at the tank and capping it there, if you're not going to be using it.

Definitely go shopping for a new rubber filler boot.  That'll let fumes leak into the trunk and they'll get sucked into the cabin.  It won't affect your fuel supply issues though.  The little tiny tank vent line needs to be open.  The PO put a screw in mine, so when I reinstated the fuel return line, I was pressurizing the tank and a pOOf of air would come out when I took the gas cap off.  With the fuel return line and tank vent line both plugged, you'll create a vacuum in the tank.  That's not good either.  Either run the vent line through a hole in the trunk, or connect it to the stock air cleaner under the hood, so the fumes can get sucked though the carb.

 

Tom

[RainMoore]

Wow, Master Tinkerer is an understatement. As always, thanks for the super informed response.

 

22 minutes ago, '76mintgrün'02 said:

Either run the vent line through a hole in the trunk, or connect it to the stock air cleaner under the hood, so the fumes can get sucked though the carb.

 

Is the air cleaner the cylinder in the front corner on the side of the passenger side of the engine bay? because I believe that's where the blue vent line is connected, after running through a plastic container in the trunk mounted on the passenger wheel well. It then runs with the fuel line into the engine bay.

 

The return line is still hooked into the tank, I'll have to check under the battery and see what's what down there. You're recommending severing that line and capping it off at both ends? and then leaving the blue vent line that comes out of the filler neck as is?

 

I'm getting a little ahead of myself with the carb questions, as I haven't really gotten it to run yet. I'm sure I'll be posting about that soon. Probably not a bad idea to go ahead and order a rebuild kit so I can make sure everything is up to snuff.

 

Thanks again.

['76mintgrün'02]

Master typerer maybe?  Sometimes it is hard to be concise.

 

The cylindrical thing is the charcoal canister that is meant to absorb fuel fumes and the air was then plumbed into the carburetor's air cleaner in the original setup.  Your weber probably has the smaller cigar box shaped air cleaner on it now, but the big round factory air cleaner has a nipple to plug the vent line into.  Just using a little hose to take it down under the engine and letting it vent to the atmosphere should be fine.  I added a nipple to my cigar box filter, back before I upgraded to the stock filter and now I just plug it into that.

 

Disconnecting the return line at the tank and putting a cap on the tank nipple is the safest thing to do.  Plugging the line down under the battery leaves it full of fuel that could potentially lead to a leak.  My steel return line rusted through alongside the pedal box, so I cut out a section and added fuel hose there, since I'm still using the line.

 

This is sort of a tangent, but I also use a Jeep fuel filter that has two outlets.  The one in the middle goes to the carb and the one near the edge connects to the return line.  That way, when the engine is shut off, the remaining fuel pressure in the line is bled back to the tank.  The fuel bypass valve originally did that job, but mine was removed by a PO.  If you use the search feature and type in "Jeep fuel filter" you'll find lots of discussions with photos.

Tom

[TobyB]

Suggestion:

 

get some fuel hose, hook up a small temporary fuel source (a bottle with a hole drilled in the top works really well,

and is spill resistant)

and get the car to run on that.

 

There are several places that the 2002 fuel supply circuit can fail, and if you're not sure about any of it, you end up chasing

your tail.

 

For what it's worth, 'turning over' is what happens when the starter motor successfully rotates the engine, synonymous

with cranking.  The engine below would NOT turn over.  Until I persuaded it.  With a big hammer.

 

t

acetone and atf don't mix!

[RainMoore]

22 hours ago, '76mintgrün'02 said:

The cylindrical thing is the charcoal canister that is meant to absorb fuel fumes and the air was then plumbed into the carburetor's air cleaner in the original setup.  Your weber probably has the smaller cigar box shaped air cleaner on it now, but the big round factory air cleaner has a nipple to plug the vent line into.  Just using a little hose to take it down under the engine and letting it vent to the atmosphere should be fine.  I added a nipple to my cigar box filter, back before I upgraded to the stock filter and now I just plug it into that.

 

So I've determined that the blue line goes into the charcoal canister, from there a small black tube goes over the radiator and connects to the return line, which is still connected to the tank. Does this make sense? I may follow your lead and get a Jeep fuel filter.

 

I've replaced the sections of fuel line and the filter, but I'm confused about the "step up" tube. The very helpful guy at auto zone couldn't think of an option that could withstand gas without deteriorating. While much more appropriately sized overall, the lines I used are 7.9mm and still too large for the outlet nipple on the pump.

In the trunk where the main fuel line goes into the tank the plastic turns into an old cloth-covered gas line for the last 8" or so, and that's deteriorating and needs to be replaced. Should I cut part of the end of the plastic fuel line off when I do that? The two different lines seem to be glued together somehow. When I replace that section I could cut a small piece of the plastic line for the pump, but then how should I connect the replacement piece?

 

I've also replaced the battery leads, and found that both the grounds off the battery had a lot of corrosion which I cleaned. I figure that could have been what caused the pitting in the points, and the busted condensers (a set in the car and in the glove, both were ruined). The negative has a 4 gauge to the engine and a 10 gauge to a tab on the body, which i replicated. There doesn't seem to be a ground from the engine to the body. Would you add one? and if so where would you attach them? Does anyone add a ground wire from the distributor to the body or engine or is it grounded by its connection itself?

 

Thanks, once again, for all your help.

['76mintgrün'02]