• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

Fuel Pump

  • Thread starter Thread starter Paul Perreca
  • Start date Start date Oct 4, 2005

Paul Perreca

New Member
Mar 30, 2005
1,085
0
0
Oct 4, 2005
#1
  • Oct 4, 2005
  • #1
Is the fuel pump in the gas tank or is it inline? Stock i mean... I have to replace it using a higher volume pump, and while i'm at it... My Mods are in my sig, and I will be going with 24 # injectors, so what size fuel pump should i get, and should it be inline or in tank? THANKS

Paul Perreca
 

darthcual

Member
Mar 31, 2005
985
19
18
Arlington, TX
Oct 4, 2005
#2
  • Oct 4, 2005
  • #2
In tank fuel pump. That puppy will have to come off.
 

sweet88gt

Member
Jun 25, 2005
334
0
16
Venice FL
Oct 4, 2005
#3
  • Oct 4, 2005
  • #3
Its in the tank and its not that hard to replace. As far as size, if you plan big mods in the future go with the 255. I have a 190 and it seems to work for what I have done. Also I ran my 190 with 19lb injectors and my new 24lb and all you will need is to adjust the fuel pressure to work with your combo. My car is in store for some air/fuel time at the dyno soon.
 

Paul Perreca

New Member
Mar 30, 2005
1,085
0
0
Oct 4, 2005
#4
  • Oct 4, 2005
  • #4
How much worse does your car get on gas when you upgrade the fuel system like this?? And I think I'll go w/ the 190 I'm not planning on S/C it for a while lol
Paul Perreca
 
J

Jeff7477

Founding Member
Jul 2, 2001
176
0
0
Lincoln, Nebraska USA
Oct 4, 2005
#5
  • Oct 4, 2005
  • #5
gas consumption doesn't change. we have return type fuel systems so any gas that doesn't get used gets sent back to the tank
 

sweet88gt

Member
Jun 25, 2005
334
0
16
Venice FL
Oct 4, 2005
#6
  • Oct 4, 2005
  • #6
Gas mileage whats that?? I have never tried to keep my mileage as for the first year I owned the car it only racked up 4000 miles. I barely ever drive it and when I do I beat the hell out of it. The unused fuel will be diverted back via the pressure reg and how much fuel pressure you are running. The best thing to do is adjust the pressure in small increments and keep track of the mileage you get and dont be overly worried about the gas. Make sure you have enough pressure to keep it running good.
 

Paul Perreca

New Member
Mar 30, 2005
1,085
0
0
Oct 4, 2005
#7
  • Oct 4, 2005
  • #7
going from stock to the combo listed in my sig w/ 24#ers and that fuel pump... will it be ALOT worse on gas??

Paul Perreca
 

sweet88gt

Member
Jun 25, 2005
334
0
16
Venice FL
Oct 4, 2005
#8
  • Oct 4, 2005
  • #8
No I dont think it will affect it that much. Will it change,yes. Its all in your tune and how you drive.
 

darthcual

Member
Mar 31, 2005
985
19
18
Arlington, TX
Oct 4, 2005
#9
  • Oct 4, 2005
  • #9
Besides, gas mileage? I mean comon if your that concerned sell your stang and get a toyota prius. You can stop and hug every tree and still get 36mpg. And you can take pictures of your wallet fat with cash from all the money your saving. Except that hybrid cars cost so much more that you end up paying more than if you bought a regular gasoline engined car. What was my point again? Ahh yes I'll have the duck, please.
 

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
9,516
6
99
Arkansas
Oct 4, 2005
#10
  • Oct 4, 2005
  • #10
It will effect your mileage very little. The 190lph fuel pump is a good choice. It is what I run as well.

Here is a write-up for a fuel pump install I did...it might come in handy for you.

To begin a in-tank fuel pump replacement you will want to make sure you have everything you might need to make the install go smoothly and with as little down time as possible. You will want the capabilities of getting the car up and off the ground for ease of install by using either a lift or a couple jacks and jack stands. Get a friend to help you out if possible along with some hand tools. Always be careful when working under a car. The least amount of fuel in the fuel tank makes it much easier so run it low or carefully siphon it out. The Walbro (190lph) pump I got from www.50resto.com came with all the hardware included. This is quoted about the Walbro pieces: “190 & 255 fuel pumps that are marked w/ hardware will include all necessary hardware. 155 fuel pump includes sock only. The 255 fuel pump marked pump only will require the use of a HDW-9350D installation kit.” The hardware has the gasket for between the sending unit base and fuel pump inlet hole, the fuel line clips, crimps, wires, sock, pump, rubber hose and it’s clamps, and lock ring gasket (shown in pic). To go along with the below text here is a Acrobat file off of 50resto’s site that will provide better visualization to go along with the detail.

http://secure.50resto.com/images/do...s/fuel_pump.pdf

First you will want to release the fuel pressure. You can do this with one of 3 ways – 1: You can release the fuel pressure by the schrader valve behind the alternator. It looks like a tire stem valve once the cap is removed. Use a flathead screwdriver to pry in there and release the pressure while using a rag to catch any “built-up” pressure in the system. 2: You can go in your trunk or hatch on the driver side and go underneath the back panel and unplug the inertia switch. Then go ahead and turn the car on until the car dies. You will not be able to crank it up because you burnt the excess fuel off. 3: This is the easiest if time permits because alls you need to do is let your car sit overnight and the fuel pressure will release naturally. Disconnect the negative side of the battery as you will be working with electrically controlled parts.

Jack up the car safely and make sure the jackstands or jack isn’t protruding into the way where you can eventually drop the tank. Get another jack that is handy with a friend to help balance a piece of board to install underneath the fuel tank to help support it. When working under the car with the road dirt and potential fuel spray I think it is a good idea to wear some glasses to keep those things out of your eyes. Get under the car and see that there are two bolts (13mm) that hold on separate straps (2) to pin the fuel tank under the car. Undo the bolts and start to drop the tank a few inches. You will then see different connections into the top of the fuel tank. Just as well you will see the filler neck (where gas is pumped into) coming out of the side of the tank. The filler neck protruedes into the tank quite a few inches so what I did is shift the tank a little to the drivers side carefully to give me more “playing room.” I then began to pull out the filler neck by hand until it was completely out of the tank. There is a very small bolt that holds on a “handle” looking strap that goes over the filler neck which is 8mm in size. Make sure it is undone to move the filler neck where it needs to be. Keep the flexing to a minimum and only do what you need to do to get it out. Now you may lower the fuel tank a little bit more so you can have better access to the sensors/vents in the fuel pump.

Start removing the sensors by pulling up on them and using a broad flathead screwdriver to help you get under the grommets. You can do them by hand as well. Your going to need some A/C-Fuel Line disconnect tools from your local parts store to release the fuel lines off of your fuel pump sending unit (back passenger side of tank). There are two lines: 1: Sending line and 2: the Return line. I believe you can undo one of them with a flathead screwdriver (plastic clip) and the other one you will need to use the proper size fuel line disconnect tool to release it if not both of them. Now that all the grommets/vents/lines are disconnected you can start to lower the tank carefully while being VERY careful to keep any dirt from falling into the tank during the process that could cause premature pump failure. Put some paper towels in the holes to help any falling mistakes that might occur. Pull the tank over on a table or the ground for you to work on. Now is a good time to clean up the tank from any dirty debris all around it. You can also pour out all the gas and take it to a car wash and wash it inside and out and let it air dry for quite a while (depends on your time). I just left the gas in there and was careful about cleaning it and scraping dirt in the tank by accident.

Go ahead and start the fuel pump sending unit removal process by getting a brass punch (or wood) so a spark can’t be created around the fuel tank and it’s gas fumes. Draining and washing the tank will eliminate this problem. You DO NOT want to create a spark. Take the punch and put it against the lock ring and “pop” it counterclockwise to loosen it under the clamps. Remove the lock ring and gasket. Pay special attention to which way the fuel lines are pointing (that you previously disconnected) so you can install it later in the same fashion. You will need to turn the sending unit to remove the assembly out of the tank to reveal the pump/sock/wires. Go ahead and get your new fuel pump ready. Unbolt the two bolts that hold the fuel pump on the sending unit (5mm?). Undo the connection (rubber hose held on by radiator looking clamps) while removing the fuel pump filter (looks like a white sock). I used a screwdriver to pop it off. Cut the red and black wires where you have a enough room to splice into it with the new wires supplied with your new fuel pump (Walbro has them with it). Remove the fuel pump. Use your new rubber hose and match the wires together by color (solder them or crimp them). I just crimped mine nicely with the supplied crimps with the fuel pump. Put in the new pump and sock on it (put it in the SAME direction the previous fuel pump filter/sock was facing) while double checking the connections you just made. You are now ready to reinstall the fuel pump sending unit. It can only properly lay in one way and you can look in the fuel pump to see where it will lie at. Drop it in. Hopefully you were able to pick up a new lock ring and gasket to prevent leaks and have a cleaner install. Go ahead and install them in using the brass or wood punch to install it correctly. While the tank is out check the filler neck grommet (where the filler neck goes into). It will commonly be dry-rotted or rip upon removal of the filler neck. You can get one from your local parts store or at your Ford dealership. Put a thin bit of vaseline on the grommet to help it slide right in. You can do the same with the other vents/grommets.

Put the tank back on the jack/wood and begin to jack the tank back up and once you get some “wire room” start connecting everything back (the connections). Slide the tank a bit to the driver side at a little angle to reinstall the filler neck again being careful not to rip the new grommet you previously installed. Bolt the filler neck handle back on and jack the fuel tank up after you have reinstalled the fuel lines with new clips hopefully if they got broke or damaged. Jack the tank up all the way being carefully to make sure nothing is kinked upon pinning it up. Bolt the strap back up using those 13mm bolts again and remove the jack. It would be a good idea and highly recommended to replace your fuel filter. I run the Motorcraft FG800A or you can get one from your local parts store as well. Alls you need to do is go along the passenger back end of the car and see the fuel lines go in and out of a bracket where a filter lies behind. You can release it by using a flathead screwdriver to break or pop the plastic connections off that hold the fuel lines on it. You can then use the same screwdriver and start unscrewing the surrounding strap to loosen the hold-down bracket on the filter. Pay attention to which way the fuel filter is facing (some aren’t labeled to tell otherwise) so you can put the new one in the right way. You don’t want your fuel filter in backwards. Two new plastic clips should be included with your new fuel filter so you can use them on your fuel lines when you reconnect everything. Go ahead and lower your car back down and reconnect your inertia switch (if need be) and reconnect the battery. Prime your fuel system several times to fill up your fuel system before actually starting. Listen for the fuel pump to prime to make sure it is working properly. Start the car up and check for anything out of the ordinary. You are now good to go!
 

Paul Perreca

New Member
Mar 30, 2005
1,085
0
0
Oct 5, 2005
#11
  • Oct 5, 2005
  • #11
If i put in the 24 # injectors, do you think i can run them w/ my stock fuel pump just long enough to eat all of the FULL tank of gas i have?? I don't wanna siphon it out, and the car has no engine as of now... don't even know if it's gonna run... so i do wanna do the 24 # injectors to get the car running... i guess i'll just get it running on the stock 19#'s and than after that I'll swap them over - do i have to take the upper intake off to change injectors, or can it be done everything assembled?????
 

sweet88gt

Member
Jun 25, 2005
334
0
16
Venice FL
Oct 5, 2005
#12
  • Oct 5, 2005
  • #12
Just put everything together (with the 24s) and run it. The stock fuel pump doesnt care what kind of injectors you have. You have to remove the upper to replace the injectors.
 

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
9,516
6
99
Arkansas
Oct 5, 2005
#13
  • Oct 5, 2005
  • #13
Yeah, it doesn't matter what injectors you have that effects the fuel pump. Your fuel pump will suffer when you start putting down more power though. I had a stock 95lph fuel pump but I didn't want to chance a lean condition nor kill the pump so I replaced it with a 190lph unit.
 

QDRHRSE

New Member
Dec 31, 2002
1,590
0
0
Palmdale, CA
Oct 5, 2005
#14
  • Oct 5, 2005
  • #14
You really ought to get a 255. There is no increase in fuel consumption. The only downside is that it will cost you a few bucks more. If you are planning on a 190 there is absolutely no reason not to step up to a 255.
 

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
9,516
6
99
Arkansas
Oct 5, 2005
#15
  • Oct 5, 2005
  • #15
Their is no need to overdue fuel pump size just because it has no "ill effects". Let me name a couple about "bigger" fuel pumps. More heat and takes just that many more amps to run. Plus it cost just a bit more. When you get a 255lph fuel pump when a 190lph will easily support enough it isn't needed. So why get it? By the time you get a 255lph fuel pump for a blown application most need an external pump anyways. A 190lph fuel pump is enough. Sometimes whether there is slight effects it just isn't needed. That is my opinion.

Why have more fuel returning during the return line that isn't used?
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Oct 5, 2005
#16
  • Oct 5, 2005
  • #16
5spd GT said:
Their is no need to overdue fuel pump size just because it has no "ill effects". Let me name a couple about "bigger" fuel pumps. More heat and takes just that many more amps to run. Plus it cost just a bit more. When you get a 255lph fuel pump when a 190lph will easily support enough it isn't needed. So why get it? By the time you get a 255lph fuel pump for a blown application most need an external pump anyways. A 190lph fuel pump is enough. Sometimes whether there is slight effects it just isn't needed. That is my opinion.

Why have more fuel returning during the return line that isn't used?
Click to expand...
Yeah, but the 255's compliment the 4.56 gears and 42# injectors (for a mild N/A combo, of course). [other examples of going overboard].

Seriously, agreed.
 

88_GT_5_oh

Sportin' a turbo 5.0 in Canadistan
Jul 4, 2004
1
0
1
WPG/MB/CA
Oct 5, 2005
#17
  • Oct 5, 2005
  • #17
easy to replace..... i went with a 255 high psi one cause i was planning on going forced induction. 190 will cut it. but if you are planning more mods, why spend money twice just get the bigger one
 

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
9,516
6
99
Arkansas
Oct 5, 2005
#18
  • Oct 5, 2005
  • #18
HISSIN50 said:
Yeah, but the 255's compliment the 4.56 gears and 42# injectors (for a mild N/A combo, of course). [other examples of going overboard].

Seriously, agreed.
Click to expand...

I don't think we have ever agreed on this before...












 
You must log in or register to reply here.

Similar threads

F
2004 Mustang GT – Fuel Pump Not Priming
  • Fayio
  • Apr 22, 2026
  • SN95 4.6L Mustang Tech
Replies
7
Views
173
SN95 4.6L Mustang Tech Apr 27, 2026
n0v8or
N
D
Fox 88 foxbody no power to red and black wire at fuel pump relay
  • drod88
  • Dec 1, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
7
Views
300
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Dec 2, 2025
Mcmahst
9
Forced Induction Prepping for supercharger on non-stock build
  • 91fox427
  • Nov 25, 2025
  • Fox 5.0 Mustang Tech
Replies
7
Views
366
Fox 5.0 Mustang Tech Jan 5, 2026
Qtrhrse23
Q
L
1997 V6 Starting issue
  • leanzik04
  • Mar 20, 2026
  • SN95 V6 Mustang Tech
Replies
3
Views
202
SN95 V6 Mustang Tech Mar 20, 2026
Noobz347
9
Engine Donor '00 Mountaineer meet '91 Fox
  • 91firecracker
  • May 11, 2026
  • Fox 5.0 Mustang Tech
  • 2 3
Replies
41
Views
515
Fox 5.0 Mustang Tech May 28, 2026
91firecracker
9
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?