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Discussion Starter #1
I am about to replace the fuel pump in my grandson's 1997 Thunderbird LX 4.6L V8 (275000 miles).

I know this is a job (done before in other vehicles).

I know the exhaust will have to be disconnected.

Are there any other irregularities or special things I need to look out for as I begin this?

I have ordered a Spectra Premium SP1140 replacement pump. Is there any reason that this may be an especially bad choice? (we are in economy mode here - car may not have a terribly long life left)
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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The biggest thing I had to get over (after getting at the pump in the first place) was making sure the stupid rubber sealing ring stayed in place as I put the pump assembly back in.

Aside from the standard avoid-if-possibles (drain tank as much as possible beforehand if feasible - if it's over 3/4 full or so fuel will pour from the hole where the pump sits when you break the seal), it's fairly straightforward IMO.
 

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You don't necessarily have to disconnect the exhaust, just unhook the hangers and let it hang down, that will give you enough room to lower the tank enough to get at the fuel pump. Also if you are in economy mode, and if the fuel level sensor is working properly, you can buy just the pump part instead of the whole assembly for a lot cheaper. The spectra part will have a Chinese made pump in it, so if you are OK with that, you might as well get the Chinese knockoff of the Walbro gss340, which can be found on eBay for $25, or you could get the real walbro for probably less than you spent on that spectra.
 

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Discussion Starter #4
... making sure the stupid rubber sealing ring stayed in place as I put the pump assembly back in.

...if it's over 3/4 full or so fuel will pour from the hole where the pump sits when you break the seal...
Indeed, the tank is full (car broke down at the filling station) - I am siphoning tank as dry as I can get it (have bad back and can't lift much). Will watch out for the seals/orings...
 

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Discussion Starter #5
... the exhaust, just unhook the hangers and let it hang down ... if the fuel level sensor is working properly, you can buy just the pump part ...
Just in process of jacking up, haven't looked underneath yet; will keep in mind... I did buy just the pump and not the assy.

... spectra ... Walbro gss340 ... eBay ... real walbro for probably less ...
I did not know the OEM part was a Walbro - good info to know. Main reason for ordering the Spectra was combination of price (<$40) and could get it by tomorrow (2-day turnaround). Normally, I avoid chinese parts but I am ever so slightly desparate here being in a time crunch (had to loan out my truck 'til I get this fixed) and I'll probably be paying for it myself (it's my grandson's car, he doesn't care). The car is 20 years old and gradually becomming a junk heap - just need to keep it running 'til he can afford to buy a newer nicer car.

-----
 

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Spectra Premium is low end junk. I've been really disappointed with several Spectra Premium parts. Don't bash parts just because they're made in China. Spectra Premium is a Canadian company. I've noticed over the years that Canada makes some of the worst junk out there.

Recently I put a Spectra fuel module in my ZX2. It seemed so incredibly cheap, especially the fuel level sender part. It was against my better judgment to even install it, but I did. There was something wrong with the regulator and the fuel gauge sender. Took the old module apart and found a Bosch fuel pump. Ordered a new Bosch pump from RockAuto and it fit and works perfectly for half the price of Spectra junk.
 

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Discussion Starter #7
OK. Did it. Done. New problems.

Had to replace entire hanger assy - rubber grommet that pump sits in was disintegrated - went with Delphi unit from AutoZone. Car now runs fine.

New problem: originally, tank was about 3/4 full - I removed about 17 gallons from tank at beginning.

Now, after replacing all 17 gallons, gauge only reads 1/4 full. I am thinking float is impinging on something in the tank. Now removing again.

Or is there something I don't understand about how the two chambers of the fuel tank work ?? Or was the float of the new unit tied off somehow to protect in shipping and I missed it ??

Or is there something else stupid I forgot to do ???
 

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It probably either got caught on something, or possibly the arm that the float is attached to could have gotten bent or dislodged while installing. Either way, the unit has to come back out to check it, and once it is removed, the problem should be obvious.
 

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The float/pump assembly slides up and down slightly; make sure the float is not binding, and is a low as possible.

Low is AWAY from the fuel hat. :)
 

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Sorry to be late to offer an idea since the job is done. You can save some headaches by CAREFULLY cutting an access panel under the rear seat. Here is an image of the work I did with a Dremel tool. I have arrows pointing to the lines to watch out for.
 

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Discussion Starter #12
Here's the latest:

I have removed the tank AGAIN, I have removed the pump/sender assy AGAIN. There is nothing very obvious (but I only got it out as it was getting dark so I can't see.

I did plug the removed pump/sender assy into the plug and moved the float around while watching the fuel gauge - it works OK (response is not immediate, have to cycle car on/off due to anti-slosh module).

So it has to be float is bumping into something as it rises at about the 1/4 tank level - hopefully get it figured out tomorrow when it is light outside.

Any thoughts on how to test when pump assy is installed before putting back in car?

[I have another car that has access panel under rear seat, what an idea - if it were something I might have to ever do again, might be worth it...]
 

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Here's the latest:

I have removed the tank AGAIN, I have removed the pump/sender assy AGAIN. There is nothing very obvious (but I only got it out as it was getting dark so I can't see.

I did plug the removed pump/sender assy into the plug and moved the float around while watching the fuel gauge - it works OK (response is not immediate, have to cycle car on/off due to anti-slosh module).

So it has to be float is bumping into something as it rises at about the 1/4 tank level - hopefully get it figured out tomorrow when it is light outside.

Any thoughts on how to test when pump assy is installed before putting back in car?

[I have another car that has access panel under rear seat, what an idea - if it were something I might have to ever do again, might be worth it...]
If you get the float working, do yourself a favor and before you congratulate yourself, make sure that gasket seal is good by filling up the tank all the way up (i.e. so the fuel level is higher than the gasket and going up the fuel neck). I found out at a race that my gasket was NOT good and fuel was actually leaking... I also learned that you can hold at least 1 gallon of fuel at the level above the gasket level (because at least that much leaked out as I was rapidly trying to fix the shitty gasket).

Luckily for us, we have an access flap so it's a quick job.
For you, it's much less fun if you have to drop the tank everytime you need access to the pump.
 

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Guys, if you open an access panel there, I'd use metal shears; cutting it with a cutoff wheel is asking for problems.

:surprise:

Just don't weld it back closed, ok?

:)
 

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Guys, if you open an access panel there, I'd use metal shears; cutting it with a cutoff wheel is asking for problems.

:surprise:

Just don't weld it back closed, ok?

:)

Tbirds are plentiful enough at JYs -- you can always cut an access panel from a JY tbird to cover the hole you make in your own car.
-g
 

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Discussion Starter #16
Anyway, I have determined that there is interference inside the tank with the float on the new unit (must be hitting on side of anti-slosh resevoir). The sender checks out when outside the tank (reads 15 ohms at empty position and 160 ohms at full position and everything in-between). I checked with AutoZone and they will not take the pump back for refund since it has been installed (they don't carry a suitable alternative to get credit for). Looks like I am stuck with modifying it so the float moves freely in the tank. At least I can test it before putting in car and filling up by turning tank upside and measuring sender resistance (should go to full position if not interfering).
 

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Do you still have the original sending unit assembly? If so you can get a Bosch OE fuel pump and lock/o-ring for about $60 on RockAuto.
 

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Look carefully at the mount for the float assembly; the float needs to be ~1-2" off the bottom of the tank fully extended, and swing up to the max without hitting anything.

The assembly will slide, so it's adjustable.

If it's too high, a full tank reads 3/4, and drops off fast.

If it's too low, 1/2 tank will read full, and then drop like crazy at the end. :)

It's also easy to put a tube or something in the way of the float; look at how it's routed, and route it the same way.
 

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Discussion Starter #20
Looks like we have it - if the sender rheostat is supposed to slide, it wasn't obvious - it appeared welded to the pickup tube.

Anyway, looks like we got it working - the new unit had a bit of an elbow that protruded laterally and was probably bumping into the side of the anti-slosh resevoir. On this model, the float detached easily from the rheostat arm to allow for some easy manipulation ("bending"); I made a few little tweaks after making some reference marks on a piece of paper, so that the final version had about the same swing as the original but with less "wing spread".

After reinstalling, we tested by flipping the empty tank over to make sure the resistance went back and forth between 160 and 15 ohms, which it did nicely.

Tank is now back in car and has about 12 gallons of gas (gauge reading between 1/2 & 3/4, which is acceptable) and no leaks. But battery ran down in the meantime fixing other things, so car has not fired up yet (but I have bled the fuel lines by applying 12VDC to pump wire in harness and fuel spews out just fine and dandy).

Hopefully, after dinner, battery will be charged and it will start up.

FYI, this is no show car or a museum piece, it is almost a clunker that my grandson drives until he can afford a nice pickup truck. However, I do have first option to buy it back from him when he trades up, and I may make some restoration/improvements if/when that happens.
 
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