What PN Walbro 255LPH fuel pump?

[bronchole]

I am looking to replace the fuel pump in the tank of my 1997 Mercury Mountaineer 5.0 with something that can handle the 331 stroker engine I am installing. The engine tuning person I am using suggested installing a Walbro GSS307 or GSS315 or GSS317 255LPH pump in conjunction with an adjustable fuel pressure regulator set to ~58PSI. Which of these Walbro fuel pumps should be the correct model to replace the stock fuel pump?

Dan

 

[CDW6212R]

The stock fuel pressure is lower than that 58psi, the return type fuel system runs at about 35psi, and raises to about 42psi under WOT(low vacuum). Ask your tuner if he knows this, and the 1999 up Fords use returnless fuel systems. Those run at a constant 62-65 psi, with the FPR in the tank with the pump.

Those pumps are different for each kind of fuel system, be sure you are going with the matching system and pump etc.

 

[donalds]

Walbro GSS342 Intank Fuel Pump 255LPH High Pressure

Do your research fakes are everywhere

 

[CDW6212R]

Walbro GSS342 Intank Fuel Pump 255LPH High Pressure

Do your research fakes are everywhere

That's the most known Walbro pump, I know that one. The others the OP listed I haven't heard of. I'm somewhat sure the same pump needed is what fits most Fords, and the Mustangs.

 

[donalds]

That's the most known Walbro pump, I know that one. The others the OP listed I haven't heard of. I'm somewhat sure the same pump needed is what fits most Fords, and the Mustangs.

Yes sir its running in my oem style sender

 

[bronchole]

The Tuner said that I need to select the pump that most closely matches the screen/filter on the bottom of the stock pump. He also mentioned that the plug may not be the same so I may need to deal with that.

The reason for the higher pressure is so that I can run the stock injectors at a higher lb/hr rate. I am attempting to get this 331 to pass the CA smog testing. From what he says if I go with the 24lb/hr injectors and stock pressure it will run better, but will not pass smog testing. Running the stock injectors at a higher pressure should run good thru about 5500 RPM and pass smog testing.... Hopefully.

Its that 5500 RPM limit that messes with everyone. Fortunatly for me this motor is a 100% torque build, not HP build. I do not intend to ever exceed 5500 RPM so I am good.

I'll look in to the Walbro GSS342. The important thing was the 255LPH High Pressure and that it "fit". Seems like Donalds is running it in his 99 returnless so hopefully it will work in my 97 return type system with the Aeromotove adjustable fuel pressure regulator I also need to run.

 

[bronchole]

Well this helps allot:

It looks like there are basically 3 varieties of the Walbro 255 fuel pump and the differnces are the fuel filter inlet size/location:

Images stolen from this page: Universal In-tank Fuel Pumps

From looking at the replacement fuel pumps on Rockauto, I can see the version I need has the 11mm inlet that is in-line with the fuel line out fitting. According to the images above that verifies that I need th GSS342. Probably should get it with the sock and plug just to make sure I have what I need to complete the installation.

BTW, gotta love living in Commifornia. Amazon will not ship these to me because it may violate local laws. I'll find another way though.

 

[bronchole]

Oh, and look at this, all the stuff I need in one place: 1996-1997 Explorer

 

[CDW6212R]

You might want to get an OEM fuel sock at least for fitting purposes, I use them and a couple of other brands I like. They fit by matching the hole inlet size, and the tiny nub which presses into a hole on the fuel sock. So it's easy to see which will bolt in.

I don't know about your tuner, I have read that it is not that hard to pass emissions with a quality engine and decent tuner that get's it to run with ideal A/F ratios.

The 332 engine size should need 30lbs injectors, or the 24's will be pushing the limit. I have read more of examples that are running over 6k rpm, which is a math factor you can do easily. I have 30's that will run the 347 in my Lincoln, but I have any emissions problems here yet.

 

[bronchole]

The trick to passing SMOG in California is to do it without any changes to the ECU. Starting pretty soon they will be checking to see if the ECU
has been altered from its factory programming. If it has... FAIL! If not, then they will look to see if it passes all the testing they do now.

With that in mind, I need it to pass without a "tune". That's the reason for going this rout. Then when I want it to run right I pull the original ECU and replace it the the tuned ECU. When smog time comes again I put the un-modified one back in and run it a couple hundred miles and go to SM
OG.

So, how to pass SMOG without re-tuning and without replacing anything that is too obvious for them to check. The red anodized fuel pressure regulator is getting a coating of flat black paint to keep it from screaming "hey I don't belong here". Everything else is completly stock appearing so I should be pretty good, assuming this works.

As for running the 24lb injectors at a higher PSI to achieve the desired output, trial and trim will tell what the desired PSI will need to be.

 

[CDW6212R]

Making the engine run okay by just altering the fuel pressure isn't enough to have it run well, that was the original way people "tuned" EFI engines. Back in the early EFI days, the only thing available was an adjustable FPR, and then they created calibrated MAF's. Those were ways they used to trick the system into achieving a decent usable air fuel ratio. Back then the result wasn't a fine tuned engine, usually they ran rich much of the time. But the point was to have it run well enough at WOT to not cook itself down.

Today's tuners may be able to do a better job with those things, but I doubt it's good for passing an emissions test.

The one good thing you have going for it now, is that the PCM is not tied to the PATS module or the VIN. You can swap the PCM at any time, for any other same model PCM. So it's an early 97 with internal EGR, which is the same PCM as all 96's too. Or it's a late 97 PCM with external EGR, which is a half year only run for that computer.

 

[bronchole]

Mine is a Late 97 with the external tube from the header to the EGR stuff. I already have 2 spare PCM's so that is not an issue. These PCM's are the exact same code as the PCM that is original in my Mountaineer. They even match the tag on the firewall. I have tested one of them, waiting till after the engine swap to test the second one. The original one will be the one I keep untouched for SMOG purposes.

I will be having a "tune" applied to one of the spare computers for normal daily driving. Then when SMOG time comes, I'll swap in the original PCM, drive a couple hundred miles and have the SMOG test ran. Once I pass, swap the PCM's back and drive for another 2 years.

As far as I can tell, this is the best solution to my California SMOG testing issue. I cannot have an altered PCM, it will be detected during the SMOG check, so this is what I am left with.

 

[Blk2kXLT]

The SMOG testing these days in CA appear to just be an OBDII scan and idle run. Passed smog with a tuned computer in another car. I am not sure what checksum or area the CA smog is actually checking.

What are you referencing 5500rpm for? I know you need a sub 3k ~10min drive to get the "cat ready" signal portion of the emissions.

I passed CA smog with a mid RPM CEL for years since just checks idle. (later fixed with returning the flow screen to the MAF) I would think that the stock PCM would dial back the duty cycle of the larger injectors as to not throw a code. What lb/hr are the stock units?

 

[CDW6212R]

Stock injectors are 19lbs, running those 24's with a stock tune will make it rich at certain times depending on the fuel pressure. The timing and fuel are not a linear curve that can be altered perfectly by the FPR, I don't know how a stock PCM with 24lbs injectors, on a 332 engine size, will pass emissions for a 302 Explorer. I think it would be better to find a testing facility that is used to non stock engines, make friends and tell them the size and hope they understand the minor changes. I've never had to go through that BS, so I feel for anyone who has to deal with it.

 

[Blk2kXLT]

Running rich should not be an issue unless it throws a code. You really just need to get all the sensors to the SMOG ready state and know that your won't throw a CEL at idle.

 

[bronchole]

Smog for a car registered in the LosAngeles area consist of:
- Visual inspection to make sure nothing stands out as modified. The always check the C.A.R.B. (California Air Resources Board) number for my Torque Monster headers. A few checks ago they made me go back to a stock air intake system. I had a MAC air on it that didn't have the C.A.R.B. number.
- Check to make sure the CEL come on with the ignition.
- Check the OBDII to make sure that there are no codes and that there has been sufficient miles and cold start since the last time the CEL was reset.
- Very soon they will also be checking to make sure the programming in the PCU has never been altered from factory default. I think this is starting in 2023.
- Check the diameter of the hole the gas nozzel sticks in. To big is a fail.
- Check the vent in the gas cap.
- Pull it on the rollers and stuff a sniffer up its exhaust.
- Check the exhaust gasses at idle and at several roller speeds.

I have never had them check the C.A.R.B. numbers on my catalectic converters, but from what I have been told if you use out of state cats, they don't have the California only C.A.R.B. numbers on them and they will fail it if they notice them.

So ya, SMOG checks in CA are a PITA.

 

[Blk2kXLT]

You should email MAC to get the sticker for the CARB number to pass.

Just passed CA smog with the 87 tune that comes on the SCT X4 programmer.