1982 Vanagon - Fuel line & Filter Question

[Sluggo]

My only helpful info on this. You can get excellent Braided, German, High Pressure Fuel Hose from any Porsche dealership.

[Lanval]

Sluggo,

Thanks ~ there's a huge Mercedes dealership nearby too, and I assume they use equivalent products. This time around I order the kit from Van Cafe; now that I know more or less what I'm doing, I'll source the stuff locally and maybe save a few bucks. Bet the Porsche dealer won't give me any cookies though...

On the issue at hand: Being the impatient type, I didn't wait for Colin's response, but went at it. The upshot is that there must be more than one type of gas tank, or my pal's gas line setup is trickier than it looks.

What I found currently on the car was this:

gas filter = 12mm in AND out
gas tank outlet = 12mm

No way is a 7mm hose gonna fit on that gas tank. NO WAY. Even if it did, I'd be worried about gas flow issues; so:

I installed new gas lines to eliminate the immediate danger, and reinstalled the old gas filter (which was black like the soul of my diss. advisers) until I can get a correct replacement.

Once I get the filter issue, it's on to the main problem ~ crappy gas mileage. I'm only getting 10-11mpg now, and that sux. Engine runs pretty cool though.

Once the gas line issue is fixed (I'm thinking there might be an issue exacerbated by the lousy filter) then it's on to the other likely culprits.

Thanks,

Lanval

Addendum: After looking around, I see that all the vendors offer the same fuel filter that I have (small intake, large output); I'm wondering if there is a non-original gas tank in my van... since this filter for the 68-73 fuel injected Bus looks about like the one I have on my van now:

http://www2.cip1.com/ProductDetails.asp ... -133-511-C

So back to you Colin ~ do you know why the tank I have has a 12mm outlet, and was that standard at an earlier point in VW history?

Best,

Lanval

[Amskeptic]

I assumed that there should be 12mm line coming from the tank to the filter (as is currently the case with my van), but the filter CLEARLY is NOT meant for that size line.

On the intake side of the filter (side opposite the indicated direction of the flow arrow) the intake is too small for a 12mm line. The output side, however, fits 12mm perfectly.

So is this correct: 7mm tank to filter, 12mm filter to pump, 7mm from pump onwards?

If so, will it matter if the 7mm hose I use is the BMW stuff that I got from Van Cafe?

The line to the filter is the smaller, the outlet to the pump is the big one, and then we're back to smaller on down. Why do they do this? Well, the larger diameter from the filter to the pump is to prevent the pump from cavitating at start-up. The only place in the entire fuel loop that could draw down to a negative pressure is between the resistance of the filter media and the inlet to the pump. So I think it is serving as an "accumulator".
Colin

[Lanval]

OK,

I went to a local VW guy that has done work on Van, and talked it over with him and figured it out, sort of.

My van has an 11mm outlet from the tank to low pressure filter, and the filter is 11mm on both sides. This is an OEM style in-line filter.

My guy called a pal in VW parts, and confirmed that this 11mm in/out square filter was visible on his screen, but there was no part # associated with it, and when the parts guy clicked on the picture of the filter, the system returned a "NLA" message.

So my options are this:

Somehow find a NOS original filter
Get a new gas tank with a 7mm output
replace the current filter with an adjustable aftermarket filter
add the inline filter after the pump, and simply delete the pre-pump filter.

I went with #3, and I'm going to add the post-pump inline filter (since those gas lines should be changed anyway, now's the time to do it.).

I'll check around and see if I can find any of the NOS filters somewhere.

Thanks,

Lanval

[Amskeptic]

My van has an 11mm outlet from the tank to low pressure filter, and the filter is 11mm on both sides. This is an OEM style in-line filter.
VW parts confirmed that this 11mm in/out square filter was visible on his screen, but there was no part # associated with it, and when the parts guy clicked on the picture of the filter, the system returned a "NLA" message.

1)Somehow find a NOS original filter
2) Get a new gas tank with a 7mm output
3) Replace the current filter with an adjustable aftermarket filter
add the inline filter after the pump, and simply delete the pre-pump filter.

I went with #3, and I'm going to add the post-pump inline filter (since those gas lines should be changed anyway, now's the time to do it.).

Well, I apologize if I am giving you addled advice, but I have my Vanagon Bentley on my desk here, and they have lousy photographs and extremely terse copy. Under the Digifant, the prefilter is NOT to be used with pumps that have their own filter already. So put that in your pipe and smoke it. We have to use our wits, that's all there is to it.
I will say from only an intuitive place, that I would like a filter before the pump. Rust chunks in the pump seems more $$ than pump wear in the injectors. Any post pump filter has to be high pressure metal can style.
Thank you.
Colin

[Lanval]

Colin,

On the contrary, your advice is sound ~ what is less satisfactory is the state of information for VWs of this vintage.

I've done a fair amount of reading on the Samba in both the Bus and Vanagon sections; no one has directly addressed this, but the problem I'm having is clear.

It's quite clear to me that by the mid 80s or later, the gas tanks were using an 11mm outlet, and running a 12mm line directly to the pump, with NO pre-filter.

The only answer for that change from the earlier set-up that I've seen is a rumor of a VW TSB that argued Vanagons should have the pre-filter removed, and run a 12mm line directly to the pump, with the canister filter on the post pump side. The claim made is that this alleviated a pressure/supply problem to the pump, caused by the filter.

addendum: Here's a parts supplier that seems to confirm this decision:

http://catalog.worldpac.com/ibusiness/J ... uel+Filter

As an answer, this doesn't make much sense to me, for the following reasons:
1) I've seen too many vans running either the pre-filter only, or the pre AND post-filter, and they seem to do so happily.
2) Over on the Samba, Tencentlife worked out the fuel supply numbers to verify that (on the WBX at least) the fuel supply was at least 3x what the engine needed at any given point, necessitating the flowback system.

Nathanael's van (the 80 model Vanagon, CA emissions) is clearly running a small line from the gas tank (7mm) to a square filter of the type I bought from NAPA.

I have looked all over the internet, including German websites to find the correct pre-filter. It is no longer available. For my fuel line system the pre-filter MUST have a 12mm in AND out. Such things WERE made (heck, there's on one there right now) but apparently are no longer available.

My answer as to what I'm doing at this point wasn't clear, so let me be clear now: I think you are correct, and my only question is where to find a blankety-blank filter that fits...

I bought the post-filter, and I'm going to add it in, to help out the injectors.

I also bought an aftermarket clear fuel filter with replaceable tips to run in the place of the pre-filter, but they're not big enough (the largest tip is 5/16, which turns out to be around 7-8mm).

So I guess that I'm going to cut a piece of 7mm BMW fuel line, and put it over the 7mm intake of the pre-filter, and then insert that setup into the 12mm line coming from the tank. It's bogus, but if someone knows where to get the OEM 12mm in/out, I'd be mighty beholdin', as it were. The filter that's on there is who knows how old... yikes.

In the long run, I'd like to drop the tank, and at that time I guess I might as well swap it out for one with a 7mm outlet, but I have to say that given the number of guys crying about pump cavitation with the 7mm output (and they're not running the pre-filter!) that answer don't make me too happy.

I trust you by definition Colin, so no need to be concerned there ~ I also noticed the not-very-satisfactory diagrams and explanations for this particular part of the fuel system in the Bentley, and I can report that the Haynes uses the exact (exact!) same diagrams, and offers no meaningful help.

If I have time tomorrow, I'll go to a VW dealer and see what they say, but after the guy I was talking with called them himself, I ain't too high on my odds of getting what I want.

I'm wondering though, what all the other Vanagon guys are doing ~ have they all switched to the post-86 style when the 12/12mm filter went NLA? Dunno...

BTW, I'm planning on seeing you next year ~ pencil me in! No crappy economy or evil grad school people can usurp that pleasure!

Best,

Lanval the Confused

[Amskeptic]

The only answer for that change from the earlier set-up that I've seen is a rumor of a VW TSB that argued Vanagons should have the pre-filter removed, and run a 12mm line directly to the pump, with the canister filter on the post pump side. The claim made is that this alleviated a pressure/supply problem to the pump, caused by the filter.

Over on the Samba, Tencentlife worked out the fuel supply numbers to verify that (on the WBX at least) the fuel supply was at least 3x what the engine needed at any given point, necessitating the flowback system.

BTW, I'm planning on seeing you next year ~ pencil me in! No crappy economy or evil grad school people can usurp that pleasure!

OK, so my acuumulator guess may have had some traction. . . .
Tell Tencentlife that fuel flow is not based just on theoretical maximum need, it is based on volume above and beyond need to meet the requirements for cooling the fuel in very hot conditions.

It would be a pleasure to once again help your neighbor disassemble his power steering while we do the real work.
Colin

[airkooledchris]

the part number that ETKA shows for the fuel filter on 1980 to 1985 Vanagons is 133-133-511, and they only show the one before the pump.

[albumimg]2348[/albumimg]

they look to be small and round in the picture, but all of the ones ive seen have always been those square white plastic ones, usually made in India like this:


bus depot shows them to be in stock currently for $4.50 each:
http://busdepot.com/details.jsp?partnumber=133133511


1986 and up:
[albumimg]2349[/albumimg]
the 86 and up Vanagons shows two filters in one part of the diagram and just the post-pump one in another.

The number 7 on the graph above shows this part number:
1h0 201 511
This is for that metal canister style filter you see after the pump


You can see here where they reference the proper pre-pump filter being NLA, but it looks like the one you can still buy if you look for the 80-85 pre-filter (133133511)

It's funny that they show the "replacement" as a 390mm section of FI hose (N-020-300-1)


I unfortunately cannot comment on the size of the line coming into the filter and then out of, in terms of how that varies from model to model, but I thought the late baywindow fuel filters worked on the aircooled vanagon models (its the same part number.)

[bus71]

Our 80 Vanagon uses the 7mm tank outlet, square filter with small in, 12 out to pump, then back to 7mm. No problems at all. I wonder if some engineer was thinking too much later on?

[Lanval]

they look to be small and round in the picture, but all of the ones ive seen have always been those square white plastic ones, usually made in India like this:



1986 and up:
[albumimg]2349[/albumimg]
the 86 and up Vanagons shows two filters in one part of the diagram and just the post-pump one in another.

The number 7 on the graph above shows this part number:
1h0 201 511
This is for that metal canister style filter you see after the pump


You can see here where they reference the proper pre-pump filter being NLA, but it looks like the one you can still buy if you look for the 80-85 pre-filter (133133511)

It's funny that they show the "replacement" as a 390mm section of FI hose (N-020-300-1)


I unfortunately cannot comment on the size of the line coming into the filter and then out of, in terms of how that varies from model to model, but I thought the late baywindow fuel filters worked on the aircooled vanagon models (its the same part number.)

Kris,

And that's the square white filter that I got at NAPA ('cept theirs is made Israel) but it's different from what I actually have on the van in that there is a size difference between the intake and output.

In fact, according to VW, a hose IS the replacement for the pre-filter; the later Vanagons got the post-pump filter only. The late Vanagons also have a filter INSIDE the gas tank, which I somehow suspect the early Vanagons don't have.

THis is why I'm wondering if in fact I have a later VW tank in an early model. On the late Vanagons, according to VW, there should be a 12mm outlet on the tank, running straight to the pump via a 12mm fuel line with no filter.

On the early models, apparently its normal to have a smaller outlet on the gas tank ~ 7mm. But there doesn't seem to be any obvious source of documentation that says when tanks/filters/etc. changed.

Basically, until I can find a filter that will fit the pre-pump setup, I'll run the regular filter with a 12mm line over a piece of 7mm line on the input side.

I wish I could figure this out. As a sidelight, the pump cutout today for awhile (looks to be original) and I'm thinking it may be near death due to strain. Any problems with getting a Bosch unit from CarQuest/NAPA?

Best,

Lanval

[airkooledchris]

Any problems with getting a Bosch unit from CarQuest/NAPA?

on the PLUS side you can take it back under warranty if it fails anytime soon. I don't know what the negatives would be, so long as its correct for your vehicle.

tomorrow ill take a peek under my 81 and confirm what size outlet's on my tank currently.

[airkooledchris]

maybe you do have a different tank in there from what was stock.

mine 81 Federal model has (currently) just the small square filter before the pump, and the outlet from the tank is very small, and the outlet of the filter is larger. it looks like mine is the 7mm variety....

if you have a later model tank, then maybe you have a filter already in the tank for the pre-pump setup.

I think I also now see the flaw in my own thinking, as I was going to use this metal canister filter PRE pump, to replace the cheap plastic one. someone on thesamba had mentioned going to the metal kind Vs the plastic just because its a better longer lasting filter. if its made specifically to be for high pressure (post pump) perhaps it could end up starving the fuel pump if I were to put it before it. (also the metal canister later model filter has a small in and out, it lacks that larger output to ensure the pump doesn't starve and burn up (from what Colin mentioned above.)

perhaps I just wasted my money on this filter. not sure ill bother putting it in after the pump if mine never had it to begin with, it would just create another point where the system can fail.

[Lanval]

Kris,

I'm actually planning to put the post-pump filter in. According to Tencentlife, there is a difference in the filtering capacities of the two; the latter, post-pump filter is intended to protect the injectors from stuff small enough that the pre-filter will/would let it through. Or so I understood his argument when I was reading late at night last week.

If true, that would pose at least one question ~ is there a difference in injectors from early to late? If the early injectors were designed within the specs of the original style filter, then it's unnecessary to add the post-pump filter.

I'll note, though, that VW themselves seem to be concerned enough about the pre-pump filter issue to add a filter into the gas tank, as you've noted.

Whatever ~ I put the new filter in with my makeshift fix, and it worked. My mileage is up, the van ran, etc.

When I get a chance, I'll pick up the bracket for the filter after the pump and see if that makes any (negative) difference.

Best,

Michael L

[Amskeptic]

I'm actually planning to . . .

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[chitwnvw]

I'm actually planning to . . .

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