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Discussion Starter · #1 ·
Hello all!

I'm new to the forums and I'm looking forward to learning lots from all of you!

I have a 1973 Valiant (Slant 6, 225) and am flummoxed by something I came across in the course of replacing my fuel pump (car's been tougher and tougher to get started... finally without starting at all...).

So, my manual says that the 1973 fuel pump has replaceable filter IN the fuel pump itself (this makes sense to me as the line to the carburetor is solid (i.e. no in-line fuel filter)). The fuel pump that I just pulled out of the car this afternoon is a Carter 0-1994 and definitely does not have a removable fuel filter. None of the replacement pumps I've found online appear to have this removable fuel filter either (Delphi MF0018, though the connections don't seem to fit with the outgoing line on this anyhow).

What am I missing here? Has this car been driving around without any fuel filter at all since I bought it last year? Do I need to somehow add an in-line filter? Where can I find the correct fuel pump?

I'm really just beginning to learn about car repair (though I'm generally pretty handy), so any ideas are really appreciated.

Thank you!
Kristin
 

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I've never heard of a replaceable filter inside the fuel pump. They are always in-line between the fuel pump and the carb.
 
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Welcome to Allpar. A replaceable filter inside the fuel pump is also news to me. Perhaps it was a one-year-only experiment that failed, and they returned to the standard pumps the next year. In your vintage, as already reported, the fuel filter is between the fuel pump and the carburetor. If the car has been sitting for a while, the gas tank might have developed internal corrosion, so you might want to put the filter in the line before the pump, where it's easy enough to both see and remove, and examine it periodically. I personally prefer the plastic filters that allow you to see the condition of the element. I've seen filters for 1/4, 5/16, and 3/8 inch fuel lines. The 5/16 size should work, but you might want to make sure first.
 

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Stock fuel filter location on a 73 Dart with /6 is in the vertical line in between the fuel pump and carb on the drivers side of the engine.
 

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The manual is incorrect. I have Petersen's Complete Book of Plymouth, Dodge, Chrysler, which specifically shows a full tuneup on a 73 slant-6 in a Duster (will be the same as yours).

There is no filter in the pump. The only gas filter is inline just before the carburetor, and is a canister roughly 2 inches in diameter and about 4 inches long, that clamps in place with short rubber hoses on each side of it. If you have a solid metal fuel line all the way from fuel pump to carb, that's an aftermarket modification.

Someone has redone this vehicle, and maybe there is a filter installed in a modified location such as in the fuel line between tank and pump (although it should not go there). Or worse, it has no filter anymore.
 

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The 1973 factory service manual does mention an in-pump filter for 6-cyls. It apparently threaded into the pump outlet tower:

"Fuel Filters

There are two fuel filters in the present fuel system. One is part of the gauge unit assembly located inside the fuel tank on the end of the fuel suction tube. This filter does not normally need servicing, but can be replaced if necessary.
The second filter (8 cylinder engines) is a paper element sealed, disposable type unit, located in the fuel line in the engine compartment, either before or after the fuel pump depending on the engine used. This filter should be replaced every 24,000 miles.
Six cylinder engines are equipped with a filter that is integral with the fuel pump. See the Fuel Pump Section of Group 14 of this manual. This filter should also be replaced every 24,000 miles".

On a 47 year-old car, it is likely NOT the original fuel pump. The original pump would have been a Carter MFS-6352S.

See chapter 14 for the Fuel system. A picture of this filter is shown on p. 14-62. It was probably the 'forgotten filter' like HVAC cabin air filters are nowadays. Out-of-sight, out-of-mind and not real easy to get to:
1973 Dodge Chassis Service Manual
 

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But all slant-6 engines do have the inline filter just before the carb, as shown in this picture.

 
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Discussion Starter · #8 ·
Hello all.

Thank you all so much for your replies! I've been trying to post a picture of the engine compartment so that you all can see that there is indeed no in-line fuel filter between the fuel pump and the carb-- only a solid line, but no luck with the pictures! So:

1. What would you recommend I do? Should I install a new line that can accommodate a filter here?
2. What fuel pump would you recommend I replace this one with (1973 Valiant, 225, Slant 6)? I've had some trouble finding anything like the Carter 0-1994 that I removed from it last week and two different parts stores have told me they have nothing in their systems for this part.

Thank you!!
 

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I see a Mopar 3780147 for your application. There is this on ebay:
73 Dodge Plymouth 6cyl Carter Fuel Pump NOS 3780147 for sale online | eBay (at https://www.ebay.com/p/73-Dodge-Plymouth-6cyl-Carter-Fuel-Pump-NOS-3780147/1939696509 )
If it has been sitting on a shelf since the mid-'70's, the rubber may have dried out and it may begin leaking? It looks fine from the outside, but 45 year-old NOS may be risky.
RockAuto lists an 'alternate' part # M60577 that may be fresher?:
1973 PLYMOUTH VALIANT 3.7L 225cid L6 Fuel Pump | RockAuto (at https://www.rockauto.com/en/catalog/plymouth,1973,valiant,3.7l+225cid+l6,1243044,fuel+&+air,fuel+pump,6256 )
Do these physically look like the one you have? You would want to add an in-line fuel filter for anything that doesn't have one yet.
 

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Napa's web site shows one at 187 S. Hudson in Seattle for $23.99 -- Part # B0275P.

Yes, I'd install a separate filter. When you say the fuel line is solid, do you mean that the line from the pump to the carburetor is all metal, or is it unbroken rubber? If rubber, it should be easy enough to cut it at a place that's far enough away from the intake manifold and easy for you to access, similar to the picture that Bob provided, and put the filter there. An all-metal line can also be cut, but it will take a bit longer, and you'll need to cut in two places to leave you enough room for the filter and its rubber hoses.

Or you could put it somewhere in the line before the fuel pump. That wouldn't be period-correct, but it would filter the gas before it enters the fuel pump.
 

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If you cut the metal line to add a filter, the ends should be flared.
 
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I think these low-pressure fuel lines had a bubble flare instead.
 

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Hello all.

Thank you all so much for your replies! I've been trying to post a picture of the engine compartment so that you all can see that there is indeed no in-line fuel filter between the fuel pump and the carb-- only a solid line, but no luck with the pictures! So:

1. What would you recommend I do? Should I install a new line that can accommodate a filter here?
2. What fuel pump would you recommend I replace this one with (1973 Valiant, 225, Slant 6)? I've had some trouble finding anything like the Carter 0-1994 that I removed from it last week and two different parts stores have told me they have nothing in their systems for this part.

Thank you!!
FYI: You should join "forabodiesonly". They specialize in cars like yours. Lots of parts available from members, too.
 

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Hello all.

Thank you all so much for your replies! I've been trying to post a picture of the engine compartment so that you all can see that there is indeed no in-line fuel filter between the fuel pump and the carb-- only a solid line, but no luck with the pictures! So:

1. What would you recommend I do? Should I install a new line that can accommodate a filter here?
2. What fuel pump would you recommend I replace this one with (1973 Valiant, 225, Slant 6)? I've had some trouble finding anything like the Carter 0-1994 that I removed from it last week and two different parts stores have told me they have nothing in their systems for this part.

Thank you!!

There was a safety recall in January 1973 for the fuel pump and gasket for the 6-cylinder engines (potential fuel leakage concern) on the Plymouth Valiant. Perhaps the pump that you have on the engine is one that was installed as part of the safety recall, or purchased later and the only type available due to the recall?

Information can be obtained by searching your year vehicle on the NHTSA.gov web site.
 
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