1. Home
  2. Automotive Technologies
  3. Re: Honda 1980 Civic Fuel Tank Connections

Re: Honda 1980 Civic Fuel Tank Connections

"Chris F." wrote in news:4af8694a$0$5328$ snipped-for-privacy@news.aliant.net:

I probably should have drawn a diagram before taking apart the fuel > system, but in my haste to finish this project before winter, I guess > I must have forgotten. Anyway, the repairs have been made and it's > time to hook up the fuel system components, but I'm afraid I'm going > to need some help. Unlike newer vehicles, this tank has a maze of > connections that doesn't seem to make much sense. To help illustrate > things, I've attached a crude drawing following this post, with > numbers beside the various connectors. The two main filler hose > connections are obvious (#1 to 14 and 2 to 13), but the rest are a > mystery. The strangest thing is an odd series of pipes - one actually > inside the other - that simply loops back to the tank instead of going > anywhere, which was originally welded to the rest of the filler neck. > Neither the Haynes or OEM manual gives even the vaguest illustration > of these connections, so I'm pretty much at a dead end. > Any help would be appreciated. > > > begin 666 FuelhoseDiagram.JPG > > Attachment decoded: FuelhoseDiagram.JPG > ` > end >

Please use one of the many free file-storage sites rather than posting binaries to a text-only group.

To keep things simple, consider that you've got four separate systems in the fuel tank area:

1) The filler neck and its vent; 2) The high-pressure fuel feed to the throttle body; 3) The low-pressure return from the TB to the tank; 4) The Fuel Evaporative emissions system ("EVAP").

You've already figured out 1). That's your #1, #2, #13, and #14.

See the oval, black rubber plug that is set into the hatch floor? That plug has three connections coming down and out of it.

My 2) is the line on the fuel pump that has the banjo fitting on it. That's #8 on your diagram. This line has high-pressure fittings all over the place. This line connects to the rubber-plug connection with the brake-type flare fitting.

My 3) is the line next to the banjo on the pump. It just slips on to the pump. That's your #7. This line connects to the rubber-plug slip-on connection which points towards the rear of the car.

My 4): The remaining rubber-plug connection that points straight down connects to the BOTTOM stub on the two-way valve. The TOP stub on the two- way valve goes right into the tank.

As for the double-line loop, I have no idea what that is.

Does this help?

Reply to
Tegger
Loading thread data ...

I have no idea either. And unless I can figure it out, I'm at a dead end. Guess I'll have to keep looking.

Reply to
Chris F.

"Chris F." wrote in news:4af98caa$0$5318$ snipped-for-privacy@news.aliant.net:

I suspect that looped line is part of something else entirely, and maybe not even from that car. I can see no function for such a piece in the fuel system of any Honda I've ever worked with or seen.

If you follow the directions I gave, can you get enough of the lines hooked up so as to make the others easier to determine? All that's left unknown are the EVAP lines, which aren't very important.

Reply to
Tegger

Believe it or not, I managed to find a decent diagram on a Honda distributors website:

formatting link
So you can see that the looped line is indeed original, though I'm still not sure what purpose it serves. The looped area was rusted through and had to be cut off, in order to save the rest of the filler neck. So I'm wondering if I need to replicate it, or if I could get away with bypassing it with short pieces of hose instead. This fuel hose arrangement appears to be unique to second-generation (1980-83) Honda Civics, so it must have been something experimental that never caught on.

Reply to
Chris F.

"Chris F." wrote in news:4af9bb46$0$5342$ snipped-for-privacy@news.aliant.net:

I see my mistake now. I had thought you had an eighty-NINE Civic. Misread the "80 for "89". Oops. I've never worked on a Honda that old.

I'm also baffled as to the purpose of that loop. At least two of the connections appear to have to do with the fuel return line, except that it also involves what looks like a two-way valve, which I ordinarily associate with the EVAP system. Maybe it's a cooler of some kind?

I'd say just loop the connections together with bulk hose and see what happens.

Reply to
Tegger

The loop is a condenser. The gasoline vapour condenses back to liquid gasoline in the loop, and gravity pulls the liquid gasoline back into the tank.

Make a loop of steel fuel line. Join the loop ends with fuel hose and gear clamps.

Reply to
M.A. Stewart

snipped-for-privacy@FreeNet.Carleton.CA (M.A. Stewart) wrote in news:hdsu4j$6hd$ snipped-for-privacy@theodyn.ncf.ca:

I wondered about that.

But then I considered what might happen if the gas condensed too soon and ran downhill on the wrong side. If it did that, it would eventually plug up the incoming vapors and block further function of the EVAP system.

I therefore, and perhaps wrongly, decided that the loop was not a condenser.

Reply to
Tegger

It would be quite a trick to replicate the rig with steel line, since it had a smaller line inside the larger one. I wonder what would happen if just omitted this condenser rig?

Reply to
Chris F.

"Chris F." wrote in news:4b044a49$0$5335$ snipped-for-privacy@news.aliant.net:

Try it and see. It's only the EVAP, which isn't particularly important.

I'd just connect the proper ends together with bulk line without worrying about the one-inside-the-other thing.

Reply to
Tegger

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.