2-port vs 3-port fuel system

[koda2000]

I was surprised to see that the fuel filter on my 2001 ST had 2 lines coming from the tank and 2 rear ports on the filter. What was the thinking behind this? It took me 2 trips to town and visits to 3 auto parts stores and Ford to find one today. Apparently, depending on build date, your truck may have come with a 2 or 3 port system.

I also need to replace my fuel pump and strainer. Are the pumps & strainers different on the 3-port system.

 

[koda2000]

Well, I drained and removed the fuel tank today. I don't get the purpose of this 3-port fuel system. It looks like the pump and strainer are the same as the 2-port system. The only difference I see is that instead of having the fuel pressure regulator dump excess pressure directly back into the fuel tank, it runs it up to the fuel filter and then back to the tank. Huh? What the heck's the purpose of that except to make the fuel filter more expensive and harder to change?

 

[4DoorFord]

Does anyone know which years use 3 port vs 2 port?

 

[koda2000]

Does anyone know which years use 3 port vs 2 port?

All I know is that my '97 SOHC, 2000 & 2001 5.0L's and 2001 SOHC Job 1 all used the 2-port fuel filters. The only one of my trucks that had the 3-port filter was my late production (Aug 2001) '01 Sport Trac had the 3-port filter. I assume the 2002 Sport Trac's used the 3-port filters, but I have no proof of this.

I'm still not sure why Ford switched to the 3-port filter. I see no advantage to it, just harder to change (and the 2-port can be hard enough to change).

 

[4DoorFord]

Hmm ok so maybe it was switched on 3rd gens and 01-03 sports and sport tracs?

 

[2000StreetRod]

2 inlet, 1 outlet filters

Those 2 inlet, 1 outlet fuel filters were used on some 1999-2001 Explorers, 2000-2003 Rangers, and 4/21/2001-3/3/2002 Sport Tracs. I don't know why they were installed. The two inlets should have no effect on reducing fuel emissions. If it was for redundancy the inlets should be the same diameter instead of different sizes.

 

[Kjhadfield]

Those 2 inlet, 1 outlet fuel filters were used on some 1999-2001 Explorers, 2000-2003 Rangers, and 4/21/2001-3/3/2002 Sport Tracs. I don't know why they were installed. The two inlets should have no effect on reducing fuel emissions. If it was for redundancy the inlets should be the same diameter instead of different sizes.

This confuses me. Only reason I ask is I have the filter on my to-do list. On rock auto my 02 lists to different filters- to 3/3/02 or 3/4/02 on. Both have 3 ports and the only visual difference is 1 is fat, the other skinny. Just based on rockauto sport tracks built after 3/4/02 still have 3 ports

Edit: just looked at ra again and it looks as if it wasn't until sometime in 04 they changed the st to 2 ports

 

[2000StreetRod]

unreliable data

I got my list from an eBay fuel filter seller and the list may be unreliable. According to Tasca Parts data base:
2001 Sport Trac to 4/21/01 P/N F89Z-9155-A
2002-2005 Sport Trac P/N F89Z-9155-A
It didn't have a listing for 4/21/01-2002.

One reason I avoid purchasing a newly released model that replaces an older one is that I've heard the factory uses up the obsolete parts before installing the replacement ones. I've also heard that manufacturers will utilize non-standard parts (when the standard parts inventory is depleted) to keep the assembly line going. An example of that is a balance shaft SOHC V6 engine installed in a Mustang that was never available in AWD or 4WD. The practice makes it hard for us that buy parts online to keep our vehicles functional.

 

[koda2000]

Those 2 inlet, 1 outlet fuel filters were used on some 1999-2001 Explorers, 2000-2003 Rangers, and 4/21/2001-3/3/2002 Sport Tracs. I don't know why they were installed. The two inlets should have no effect on reducing fuel emissions. If it was for redundancy the inlets should be the same diameter instead of different sizes.

The 3-port fuel filter inlet side fittings are not the same size. One is slightly smaller than the other. I believe the return outlet port is the smaller one. I was able to remove both the inlet side lines with the same tool (5/16) as I didn't realize they were different until I had the filter off. Perhaps they are different so you don't install them incorrectly.

I'd still love to hear an explanation as to why Ford used this type of fuel filter. I honestly can't figure out what it's supposed to do. The in-tank fuel pump is identical to the 2-port system, and the assembly looks the same except for the return line. In my case it was the return port that was completely clogged, where the through port still had flow (although it was restricted).

The 3-port filter is hard to find in-stock at parts stores. Only one of 5 in my town had it in stock (O'Reilly's) and of course the 3-port is twice the price of the 2-port filter.

Maybe the return port is supposed to act as a buffer to keep eliminate fuel pressure surges/spikes... IDK.

 

[2000StreetRod]

return port?

The 3 port I saw was listed as 2 inlets and 1 outlet. I don't understand how it would work if you're correct that one of the ports returns fuel from the filter to the tank. The fuel pressure regulator (FPR) is in the tank to maintain about 65 psi to the fuel rail. There is no fuel pressure regulator at the rail or in the fuel filter. If there is a return to the tank from the filter the fuel pressure would drop and defeat the purpose of the intank FPR. On the Explorer the rail mounted fuel pressure sensor and fuel pump pulse width modulation was not implemented until 2004. Does your engine still have the Schrader valve on the fuel rail? Do you have 19 lb/hr injectors? If there is a return line maybe it is to lower the pressure at the rail to reduce emissions. As I recall the California models had lower flow injectors to reduce emissions.

 

[koda2000]

The 3 port I saw was listed as 2 inlets and 1 outlet. I don't understand how it would work if you're correct that one of the ports returns fuel from the filter to the tank. The fuel pressure regulator (FPR) is in the tank to maintain about 65 psi to the fuel rail. There is no fuel pressure regulator at the rail or in the fuel filter. If there is a return to the tank from the filter the fuel pressure would drop and defeat the purpose of the intank FPR. On the Explorer the rail mounted fuel pressure sensor and fuel pump pulse width modulation was not implemented until 2004. Does your engine still have the Schrader valve on the fuel rail? Do you have 19 lb/hr injectors? If there is a return line maybe it is to lower the pressure at the rail to reduce emissions. As I recall the California models had lower flow injectors to reduce emissions.

As I recall the extra port is on the feed side of the filter and there's only one line leading from the fuel pump to the filter, so I assumer the extra line is a return of some sort as that line goes back to the tank. I don't know what lb fuel injectors I have.

 

[HELMUT RONER]

I learned of the fuel system parts changes earlier this year when I was researching fuel pumps. I saw an all metal fuel pump listed for Sport Trac up until 3/3/2002. Then another fuel pump (metal and plastic) for 2002 built 3/4/2002 (used until end of 2003 model). Mine was built 07/2002. Had to replace my pump due to pressure loss in the system. Had to keep priming 3 or 4 times before starting the engine. The Airtex I installed fixed the problem and starts instantly everytime. Now I'm on the hunt for the fuel hardline that goes from the fuel filter up to the engine because some jackass distorted the metal connector to the front of the fuel filter. I can't get the filter off.

 

[koda2000]

I learned of the fuel system parts changes earlier this year when I was researching fuel pumps. I saw an all metal fuel pump listed for Sport Trac up until 3/3/2002. Then another fuel pump (metal and plastic) for 2002 built 3/4/2002 (used until end of 2003 model). Mine was built 07/2002. Had to replace my pump due to pressure loss in the system. Had to keep priming 3 or 4 times before starting the engine. The Airtex I installed fixed the problem and starts instantly everytime. Now I'm on the hunt for the fuel hardline that goes from the fuel filter up to the engine because some jackass distorted the metal connector to the front of the fuel filter. I can't get the filter off.

I hope you have better luck with the Airtex pump than I did. Mine worked perfectly until it abruptly topped working. It wasn't even 2 years old. Now I buy Bosch pumps exclusively.

 

[2000StreetRod]

mystery port

Online I found the fuel pump removal section of the workshop manual for 2002 Sport Tracs built after 03/2002. It shows two hoses on one end of the fuel filter.

However, the text mentions only disconnecting one evaporative vapor tube and one fuel line from the fuel tank. Are you sure both fuel filter hoses on the aft side are connected to the fuel tank?

 

[HELMUT RONER]

Are you sure both fuel filter hoses on the aft side are connected to the fuel tank?

They are on my 2002.

 

[koda2000]

Online I found the fuel pump removal section of the workshop manual for 2002 Sport Tracs built after 03/2002. It shows two hoses on one end of the fuel filter.
View attachment 86092
However, the text mentions only disconnecting one evaporative vapor tube and one fuel line from the fuel tank. Are you sure both fuel filter hoses on the aft side are connected to the fuel tank?

On my late production 2001 ST, the 2 lines on the rear (inlet side) of the filter go straight into the filter, not at a right angle as shown in the diagram you provided. Then the outlet side has a straight single outlet (just like on the 2-port system) which goes to the engine. I'm 99.9% sure the extra inlet port went back to the fuel pump assembly. It was a few months ago, but that's what I recall. My ST is kind of buried in my lower garage right now and I don't feel like crawling under it to check, but I know I looked at it closely at the time and was puzzled by it.

If the only way to clear this up is to go take some pics of my system I suppose I can do that.

BTW, The top of my fuel pump assembly did not look like the one in the photo with the twist-on retainer. It used the more typical multiple small bolts to hold it to the tank.

 

[2000StreetRod]

end of path FPR

I found a photo of the fuel pump that explains the fuel flow.

The output of the fuel pump near the bottom of the assembly is routed directly to the outlet port that goes to the fuel filter. Then the fuel returns from the filter to the FPR which vents the overpressure fuel into the tank. One potential advantage of the revised flow occurs if the return port is post filter (same as output port to engine). That would ensure full pressure is delivered to the rail independent of the drop in pressure across the filter. It would also make the fuel system more responsive to rapid changes in fuel flow - but still not as responsive as the rail mounted FPR which senses a change in vacuum. Many race vehicles are converted from the non-return to a return fuel system to improve fuel response to rapid changes in engine load.

 

[koda2000]

Not sure why you said "the output of the fuel pump is near the bottom of the assembly" as it's actually more in the center, right below the FPR and the return is not post filter unless it's routed that way internally.

 

[Valas1969]

my 2002 ST has a 2 port fuel filter on it.