'78 FI Talk me out of this... (glass fuel filter)

Carbs & F.I.

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DurocShark
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'78 FI Talk me out of this... (glass fuel filter)

Post by DurocShark » Mon Oct 16, 2006 9:12 am

Because of the crap still floating around my gas tank, I'm changing my fuel filter monthly or so. The crap is rubber chunks, not rust.

This past weekend was a mad search for a FI filter. Stores showed it in their inventory, but couldn't find the physical filter. Almost didn't get to drive my bus today. (I finally found one 20 miles away at a Checker.)

I'm tired of this. Yeah, I can order a bunch to keep on hand. But that's expensive.

I had a glass filter with a washable element on my 73 (with a rubber sleeve I made for it to protect it from rocks and such). Since the filter is BEFORE the fuel pump (low pressure), I'm thinking about doing this for my 78. I know I have to deal with the different hose sizes on either end, but that's not an impossible task.

So tell me why I can't do this until I get a chance to pull the tank?

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Amskeptic
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Re: Talk me out of this... (Fuel Filter)

Post by Amskeptic » Mon Oct 16, 2006 9:25 am

DurocShark wrote:I had a glass filter with a washable element on my 73 (with a rubber sleeve I made for it to protect it from rocks and such). Since the filter is BEFORE the fuel pump (low pressure), I'm thinking about doing this for my 78. I know I have to deal with the different hose sizes on either end, but that's not an impossible task.

So tell me why I can't do this until I get a chance to pull the tank?
Warning
Residual pressure in FI system is greatly higher than carb systems.
Do not use glass bowl filters. Clean the tank once and for all.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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DurocShark
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Re: Talk me out of this... (Fuel Filter)

Post by DurocShark » Mon Oct 16, 2006 9:30 am

Amskeptic wrote:Clean the tank once and for all.
Colin
I thought any residual pressure was held on the rail by the fuel pump's valving?

(correct, but when engine is running, the flow is completely past any carburetor-intended filter's ability to withstand)

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Randy in Maine
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Post by Randy in Maine » Tue Oct 17, 2006 11:47 am

Anytime the pump is running the actual pump and filter should be cold to the touch.

Any noise or warmth is generally bad.

Where would you be getting rubber chunks from anyway?
79 VW Bus

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DurocShark
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Post by DurocShark » Tue Oct 17, 2006 12:28 pm

Randy in Maine wrote: Where would you be getting rubber chunks from anyway?
From the deteriorated filler neck. Repair doesn't magically remove the chunks from inside the tank, darn it. ;)

I think the frequently plugged filter caused the pump to run dry too many times. I have noticed the pressure valve in the pump to keep the rail pressure up when the bus is shut off doesn't work anymore. Also it appears to be the factory original pump. So it could just be age. Dunno. But it has been getting progressively louder over the past month or so.

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