Replacing the Fuel pump

Dudz40vt · Jun 7, 2006

I have a 90 5.8 and I want to replace the fuel pump but i'm having trouble figuring out exactly what I need to order. I was looking around at various sites and there seems to be a # of different options available but I'm not sure which one is correct...

For instance on Jeffbroncograveyard they have a fuel pump listed for 45 bux

http://broncograveyard.com/bronco/i-10286_...8_fuel_pump.htm

and then another for $225

http://broncograveyard.com/bronco/i-30257_...llon_bronco.htm

And then other sites have other various ones as well. I've seen some brand called "airtex" or something and they seem to be more expensive than any others? Any of yall know what I exactly need or where I can find out? thanks

-marc

Justshootme84 · Jun 7, 2006

Since your 90 Bronco has fuel injection (EFI), it has 2 fuel pumps. One inside the gas tank that's also part of the sending unit ($120), and one along the frame rail under the driver's-side. ($50). Shop around and check your local parts stores for prices, so you don't pay too much!!! There's also a fuel pump relay, regulator and the fuses for the pumps that can go bad. Worth checking out, since pulling the gas tank to replace that pump is a chore, JSM84

Dudz40vt · Jun 7, 2006

Wait...hm.. I was intending on replacing the pump on top of the gas tank, but ur saying theres one in the engine and one along the frame...but then you also mentioned something about pulling the tank down to get the one I was talking about...So that would make 3?

Justshootme84 said:
Since your 90 Bronco has fuel injection (EFI), it has 2 fuel pumps. One inside the gas tank that's also part of the sending unit ($120), and one along the frame rail under the driver's-side. ($50). Shop around and check your local parts stores for prices, so you don't pay too much!!! There's also a fuel pump relay, regulator and the fuses for the pumps that can go bad. Worth checking out, since pulling the gas tank to replace that pump is a chore, JSM84

BLADE262US · Jun 8, 2006

No there is one inside the tank its part of the sending unit . Then theres a high pressure one mounted in the frame rail about under the front of the drivers door . Only 2 pumps later models only have one high pressure in the tank .

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Dudz40vt · Jun 8, 2006

Hey jsm84,

sorry for all the questions but then what is sitting on top of the gas tank?? I talked to a guy who had the same problem with his bronco as im having now and he said to fix it he replaced the fuel pump on top of the gas tank

Justshootme84 said:
Since your 90 Bronco has fuel injection (EFI), it has 2 fuel pumps. One inside the gas tank that's also part of the sending unit ($120), and one along the frame rail under the driver's-side. ($50). Shop around and check your local parts stores for prices, so you don't pay too much!!! There's also a fuel pump relay, regulator and the fuses for the pumps that can go bad. Worth checking out, since pulling the gas tank to replace that pump is a chore, JSM84

Seabronc · Jun 8, 2006

Ther is no fuel pump on top of the tank, it is inside the tank. Why do you want to replace the fuel pump? Is your pressure low? Is it bad? What is the symptom?

By the way the first link you have in your initial post is a mechanical pump that is for older non-fuel injection engines like mine. That one mounts on the engine but you do not have that one on your truck.

Justshootme84 · Jun 8, 2006

Two fuel pumps on your 90 Bronco: A low-pressure pump inside the gas tank, which is part of an assembly including the sending unit. The other, high-pressure pump is on the inner side of the driver's frame rail. You have a fuel pressure regulator near the frame pump, and a fuel pressure relay to control the pump. There is no fuel pump on the engine. Hope that helps, and there is nothing on top of the gas tank other than the top ring for the inner assembly where your wiring and hoses connect.

Crankin · May 11, 2007

Where is the fuel pressure relay to control the pump located?

doitnowkid · May 23, 2007

Justshootme84 said:
Two fuel pumps on your 90 Bronco: A low-pressure pump inside the gas tank, which is part of an assembly including the sending unit. The other, high-pressure pump is on the inner side of the driver's frame rail. You have a fuel pressure regulator near the frame pump, and a fuel pressure relay to control the pump. There is no fuel pump on the engine. Hope that helps, and there is nothing on top of the gas tank other than the top ring for the inner assembly where your wiring and hoses connect.

Hi jsm84,

I see you know a lot about fuel pumps too. I wrote a thread a few days ago about fixing the fuel pump by hitting it with a rubber hammer. It worked for a while, but now I think I have to consider changing the fuel pump. I was driving around and all of the sudden I lost power and the truck almost stalled. I was able to turn around and get home. When I shut the engine it wouldn't start again. I wonder if it's the fuel filter or if it's really the fuel pump. I have a friend who had the same trouble on his ford truck, of the same year, who made the suggestion of hitting the gas tank or kicking it a few times. It seems to loosen whatever is stuck and then the truck starts up again. I hate to think about changing the fuel pump, (it's on a '94 Bronco with the 302 5.0 engine), but removing the fuel tank is not so easy. It has a skid plate underneath und it's bolted to the frame. I also have it 3/4 full of gas, which I would have to drain. :blink:

Any suggestions?

Doitnowkid

Justshootme84 · May 23, 2007

Usually, the in-tank fuel pump will make a buzzing/humming noise that you can hear when the key is turned on. Not always a sign of impending failure, but when the noise stops you're in trouble. Banging on the gas tank is only a temporary fix ( but a good one, as you've found out). Running the tank to below 1/4 tank and high mileage (over 100K mi) often leads to unexpected pump failure. It is a PITA to drop the tank and change the internal pump, but here's a few suggestions. Run the tank to empty, or siphon out as much gas as you can. Gas weighs roughly 10 pounds/gallon, so a full tank weighs close to 300 lbs. The empty tank weighs about 25 lbs. To remove the tank, you need to unbolt the filler neck from the body (3 screws) and remove the skid plate or straps. I've had hella time with some of those bolts on the skid plate. The nuts are rather soft, and will strip very easily, and are often rusted. Soak them liberally with Power Blaster or a good penetrating oil. IF the nut tries to strip when loosening it, turn the bolt from below while holding the nut with another wrench/ socket. Put a floor jack or support under the tank so it doesn't drop on you. After removing all 8 bolts from the skid plate, lower the tank enough to disconnect the wiring from the sending unit retainer ring. It's just a simple plug connector. To remove the retainer ring, use a block of wood or brass punch, NOT A METAL PUNCH OR SCREWDRIVER!!! You don't want any sparks!!! The ring turns counter-clockwise to loosen. Pull the assembly out, and change it. Check the tank for any sign of rust insdie and out. A common rust area for leaks is on the bottom, where moisture can collect bewtween the tank and skid plate. While you're at it, the filler neck hose can be removed by loosening the clamp next to the tank. There is an internal, plastic vent tube that often gets kinked. It causes that problem with filling up at many pumps, as the kinked tube keeps cutting off the vent check on the pump hose. JSM84

doitnowkid · May 24, 2007

Justshootme84 said:
Usually, the in-tank fuel pump will make a buzzing/humming noise that you can hear when the key is turned on. Not always a sign of impending failure, but when the noise stops you're in trouble. Banging on the gas tank is only a temporary fix ( but a good one, as you've found out). Running the tank to below 1/4 tank and high mileage (over 100K mi) often leads to unexpected pump failure. It is a PITA to drop the tank and change the internal pump, but here's a few suggestions. Run the tank to empty, or siphon out as much gas as you can. Gas weighs roughly 10 pounds/gallon, so a full tank weighs close to 300 lbs. The empty tank weighs about 25 lbs. To remove the tank, you need to unbolt the filler neck from the body (3 screws) and remove the skid plate or straps. I've had hella time with some of those bolts on the skid plate. The nuts are rather soft, and will strip very easily, and are often rusted. Soak them liberally with Power Blaster or a good penetrating oil. IF the nut tries to strip when loosening it, turn the bolt from below while holding the nut with another wrench/ socket. Put a floor jack or support under the tank so it doesn't drop on you. After removing all 8 bolts from the skid plate, lower the tank enough to disconnect the wiring from the sending unit retainer ring. It's just a simple plug connector. To remove the retainer ring, use a block of wood or brass punch, NOT A METAL PUNCH OR SCREWDRIVER!!! You don't want any sparks!!! The ring turns counter-clockwise to loosen. Pull the assembly out, and change it. Check the tank for any sign of rust insdie and out. A common rust area for leaks is on the bottom, where moisture can collect bewtween the tank and skid plate. While you're at it, the filler neck hose can be removed by loosening the clamp next to the tank. There is an internal, plastic vent tube that often gets kinked. It causes that problem with filling up at many pumps, as the kinked tube keeps cutting off the vent check on the pump hose. JSM84

Thanks JSM84!

Your post is very helpful, but what I was thinking is that maybe something else is wrong. I tried and turned on the key and I did hear the fuel pump start up. Then I started the truck and it ran fine. It's only when I start driving, after a while it starts to sputter and loses power and actually stops. Could it be that the fuel filter is cloged up? I have to tell you I did a foolish thing. The last time a filled up the tank with regular I aded fuel injector cleaner. I usually do this with older cars or trucks to keep the system clean, but maybe this time I losened some crud on the bottom of the tank, which now clugs the pump and/or the filter.

Or even worst, messed up the EFI system. Interestingly, I have aded this same solution before and nothing happened, the truck ran fine for the past 2 years. I am willing to change the fuel pump, but only as the last resort. I guess I am lazy. And, you are right those bolts on the bottom of the skid plate are really rusted on. So, do you think it could be something else wrong? Maybe it's just wishful thinking on my part. Like I said earlier in a post a friend had the same engine in his truck, the same year, and he said he ran into the same problem. He is sure it's my fuel pump. What do you think?

The Doitnowkid

Justshootme84 · May 24, 2007

As simple to change as the fuel filter is, i would try that first before dropping the tank. The fuel pressure relay may be going out, too.

doitnowkid · May 24, 2007

Justshootme84 said:
As simple to change as the fuel filter is, i would try that first before dropping the tank. The fuel pressure relay may be going out, too.

Hi JSM84,

Thanks for the reply. When you say fuel presssure relay, you mean the fuel pump relay? Or, is there another relay?

Doitnowkid

Justshootme84 · May 24, 2007

Yes, fuel pump relay for the rear tank if it keeps cutting off and on.

itsrickfromfl · May 30, 2007

Justshootme84 said:
Yes, fuel pump relay for the rear tank if it keeps cutting off and on.

A preventative measure while the tank is out!

I recently replaced both pumps on my 86 Bronco. At the suggestion of my brother, I replaced the vent on top of the tank, while the tank was out of the truck. The vent cost me less than ten dollars from a Ford dealer. It's a good idea to replace it at the same time, rather than risk having to drop the tank later!

kracken · Mar 31, 2009

My 1990 5.0 EFI is having the same problems. I can start my truck and it will idle fine. The longer that I drive it, the less power it has until it is sputtering and won't go. For a while when it starts losing power, I can back off the throttle and it will go fine. I've already checked and replaced the fuel filter. Is it the fuel pump?

Our older Crown Vics (03 and 04) at the PD had a similar problem a few months back when the ethanol level was raised in the gasoline, or so we were told by local stations. The mechanic changed the fuel pumps and they ran good after that. I'm wondering if it is the same situation with my truck.

I know this is an old post, but I found it searching.

BroncoJoe19 · Mar 31, 2009

I just read through this whole thread (well skimmed it actually) wondering if anyone would pick up on the fact that 1990 bronco's only have ONE fuel pump. The one in the tank.

The reason why I can remember that is becuase I own a 1990. That was the year that they switched from a two pump system to a one pump system. There are too many changes over too many years to keep track of everything, but this one I am sure of.

Kraken,

You may have enough crap in your tank that you may be clogging your filter. They are cheap and easy to replace compared to the in the tank pump. They cost a lot less also, or did I already mention that?

My brother had a rusted gas tank. He went through a filter a week until he replaced his tank.

90Bronco_EB · Oct 18, 2009

OK, My tank was way rusty and leaking fuel so I just replaced my fuel TANK, filler neck hose, fuel filter, fuel pump relay, and ACC Power relay (everything except the pump and sending unit assembly only because it is like $400!). Now the pump is not pumping fuel. When i turn on the ignition i hear a sucking sound like if you tried to **** a rock through a straw but not the buzzing/humming sounds and no fuel is being spit out of the top of the send unit.

Do I need a new pump too? What else could be wrong?

BTW, you scared the **** out of me when you mentioned that there was a second fuel pump on the frame rail... whew.

Burns · Nov 4, 2009

My pump just died. Power on and no whine from the rear. Any idea what size the bolts/nuts are for the strats/skidplate/tank are? Mine are RUSTY and I know a few will break, I'd rather replace them all at the time.

Replacing the Fuel pump

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