2 Fuel Filters?????
Thread Starter
Burning Brakes
Joined: Feb 2001
Posts: 769
Likes: 0
From: Granbury TX
2 Fuel Filters?????
I was doing some standard pm's today and while doing the fuel filter change out (never done it on this car before), I noticed a second device mounted on the frame above it. Upon closer exam, according to it's lable, it is another filter. It has a screw-on can but about the same size as the inline supply line filter. This one however, is in the return line. The discharge from the fuel regulator goes to it's inlet, and it's outlet is connected to the return line to the tank. It looks original, or at least professionally installed, but I have never heard of a fuel return line filter.
Is this stock/common????
Is this stock/common????
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
YEAR???
My 1984-1989 parts book shows the fuel filter, G481 (except 1984), installed in the line going TO the engine compartment, which is located above the return line. There IS a return line connection in the vicinity of the fuel filter location. Could someone added a filter to the return line during your car's past?
RACE ON!!!
My 1984-1989 parts book shows the fuel filter, G481 (except 1984), installed in the line going TO the engine compartment, which is located above the return line. There IS a return line connection in the vicinity of the fuel filter location. Could someone added a filter to the return line during your car's past?
RACE ON!!!
Burning Brakes
Joined: Jan 2002
Posts: 993
Likes: 4
From: Glen Burnie MD
It's a retrofitted part to reduce knocking in the fuel return line. GM put out a service bulletin around 1988 or so that covered 85 and newer, and installed it by request.
NHTSA Item Number: 90911
Make: CHEVROLET
Model: CORVETTE
Year: 1986
Component: FUEL:FUEL INJECTION: UNKNOWN TYPE:ACCUMULATOR
Summary: FUEL RETURN PIPE RATTLE/KNOCK-HAMMERING/KNOCKING TYPE NOISE-CAUSED BY PRESSURE P ULSATINGS IN FUEL SYSTEM GENERATED BY FUEL INJECTOR OPERATION-REPAIRED BY INSTAL LATION OF A FILTER-ACCUMULATOR ASSEMBLY IN FUEL RETURN SYSTEM-SERVICE KITS CONTA INING PARTS AVAILABLE FROM GMSPO-SERVICE KIT P/N-COUPE 10068791-CONVERTIBLE 1006 8797-ALL 1985-86 CHEVROLET CORVETTE MODELS
This is from the 86-year bulletin.
[RICHR]
NHTSA Item Number: 90911
Make: CHEVROLET
Model: CORVETTE
Year: 1986
Component: FUEL:FUEL INJECTION: UNKNOWN TYPE:ACCUMULATOR
Summary: FUEL RETURN PIPE RATTLE/KNOCK-HAMMERING/KNOCKING TYPE NOISE-CAUSED BY PRESSURE P ULSATINGS IN FUEL SYSTEM GENERATED BY FUEL INJECTOR OPERATION-REPAIRED BY INSTAL LATION OF A FILTER-ACCUMULATOR ASSEMBLY IN FUEL RETURN SYSTEM-SERVICE KITS CONTA INING PARTS AVAILABLE FROM GMSPO-SERVICE KIT P/N-COUPE 10068791-CONVERTIBLE 1006 8797-ALL 1985-86 CHEVROLET CORVETTE MODELS
This is from the 86-year bulletin.
[RICHR]
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Originally Posted by rrubel
It's a retrofitted part to reduce knocking in the fuel return line. GM put out a service bulletin around 1988 or so that covered 85 and newer, and installed it by request.
NHTSA Item Number: 90911
Make: CHEVROLET
Model: CORVETTE
Year: 1986
Component: FUEL:FUEL INJECTION: UNKNOWN TYPE:ACCUMULATOR
Summary: FUEL RETURN PIPE RATTLE/KNOCK-HAMMERING/KNOCKING TYPE NOISE-CAUSED BY PRESSURE P ULSATINGS IN FUEL SYSTEM GENERATED BY FUEL INJECTOR OPERATION-REPAIRED BY INSTAL LATION OF A FILTER-ACCUMULATOR ASSEMBLY IN FUEL RETURN SYSTEM-SERVICE KITS CONTA INING PARTS AVAILABLE FROM GMSPO-SERVICE KIT P/N-COUPE 10068791-CONVERTIBLE 1006 8797-ALL 1985-86 CHEVROLET CORVETTE MODELS
This is from the 86-year bulletin.
[RICHR]
NHTSA Item Number: 90911
Make: CHEVROLET
Model: CORVETTE
Year: 1986
Component: FUEL:FUEL INJECTION: UNKNOWN TYPE:ACCUMULATOR
Summary: FUEL RETURN PIPE RATTLE/KNOCK-HAMMERING/KNOCKING TYPE NOISE-CAUSED BY PRESSURE P ULSATINGS IN FUEL SYSTEM GENERATED BY FUEL INJECTOR OPERATION-REPAIRED BY INSTAL LATION OF A FILTER-ACCUMULATOR ASSEMBLY IN FUEL RETURN SYSTEM-SERVICE KITS CONTA INING PARTS AVAILABLE FROM GMSPO-SERVICE KIT P/N-COUPE 10068791-CONVERTIBLE 1006 8797-ALL 1985-86 CHEVROLET CORVETTE MODELS
This is from the 86-year bulletin.
[RICHR]
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Mine doesn't have that retrofitted, I get the fuel line rattle on cold starts. So I guess I'm 20 years late on getting that fixed? It's because of the batch fire injection.
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Melting Slicks
Joined: Jan 2001
Posts: 2,940
Likes: 5
From: Chesapeake VA
My 86' only has the "to engine" filter and not the "from engine" filter. I do get the rattle on some cold starts.
Do you mean the return filter?
If you mean the main filter, if you don't know when it's been changed, then you should change it just so you know it is fresh. It isn't hard, but you will want a large jar to catch the large amount of fuel that will run out during the process.
Originally Posted by GlennS87
is this a regular maintenance item. I don't think mine has ever been changed. I didn't even know it was there.
If you mean the main filter, if you don't know when it's been changed, then you should change it just so you know it is fresh. It isn't hard, but you will want a large jar to catch the large amount of fuel that will run out during the process.
Burning Brakes
Joined: Jan 2002
Posts: 993
Likes: 4
From: Glen Burnie MD
It's not supposed to need replacing, according to my dealer. The returning gas has already been filtered. In fact, you can't (they say) get the part any longer. Mine doesn't have it, has the knocking, and I'm apparently SOL... There is a time limit on the service bulletins... unlike a safety recall, they don't have to do it on every car regardless of age.
[RICHR]
[RICHR]
Racer
Joined: May 2004
Posts: 295
Likes: 3
From: Newton NJ
My 1987 has both filters, I recently changed both. The retro-fit return unit is still availible from GM got mine last month. Had to replace it because of crack in the top of the unit. The replacement fiters can be purchased from Autozone. 
Melting Slicks
Joined: Jul 2004
Posts: 2,018
Likes: 1
From: OR
Originally Posted by SS409 425HP
I changed both on my '87 a few years ago.
Supply line filter ---- AC Delco #GF481
Return line filter ---- AC Delco #GF157
Supply line filter ---- AC Delco #GF481
Return line filter ---- AC Delco #GF157
