Fuel Pump Sending Unit too?

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kevvan

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My fuel pump went south on my 1990 Sport. I am dropping the tank on Thursday.

Philosophical questions....
If you were doing this, would you or would you not replace the sending unit along with the pump motor?

I see some say the sending unit is not the problem and leave it in there, and others figure when you have it open, replace the whole thing.

Looking for wisdom as to how others feel about this.

Personally I feel like the wires, plugs, etc. have given their all and it might make sense to retire them with a thank you given they have been in service since 1990.
 

454cid

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I don't have experience with the early pumps. Mine is designed to be replaced as a unit. I tried taking it apart, and I quickly decided it wasn't worth it. It's all plastic. I think you have steel. I think rust on the outside.... tubes/fittings would likely be my deciding issue. That and what is actually available for replacement.
 

JavaMan

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On a 30 year old sender, yes replace the whole thing. The insulation deteriorates with age, while it's not as noticeable inside that tank, if any does come loose that's not a good place for a spark.
When I bought my Suburban, it had leaking fuel lines. So they gave me $1200 off list price, because that's what it would cost them to get it repaired (apparently the service shop charges the sales department full price, even though it's the same dealership). Since I had the tank down to replace the fuel lines, I replaced the sender and pump while I was in there. It was 21 years old, 114k miles, better do it then rather than on a road trip 500 miles from home. I painted the whole outside of the fuel tank, after sanding most of the rust off the top.

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JavaMan

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Years ago, I was on a trip in my Mustang. It refused to start after stopping for lunch. We were 500 miles from home, in a small city of 5k. Had it towed to the nearest place. Mechanic said the fuel pump went out. Quoted me $1800 to replace it. I thought that was extreme. Apparently "when the fuel pump goes out it sends debris through the whole system, and clogs other parts". He insisted on replacing the pump, sender, fuel pressure regulator, and fuel injectors along with flushing the fuel lines and tank.
He gave quite the fuss when I had my car towed elsewhere to be repaired, made me pay $100 diagnostic fee for the 20 minutes he worked on it to determine the problem.
Guy at the next shop laughed, only charged me $400.

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PlayingWithTBI

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Whatever you decide, you should clean the ground wire contacts too. On my 88 I just changed the pump (with a Vortec pump for higher pressure and volume) this past time since everything still looked almost new. BTW change the filter too!
 

kevvan

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Whatever you decide, you should clean the ground wire contacts too. On my 88 I just changed the pump (with a Vortec pump for higher pressure and volume) this past time since everything still looked almost new. BTW change the filter too!

Will do, thanks for the guidance. I ordered a Delphi replacement and a new O ring to fit under the cap. Would have preferred to go ACDelco but after reading reviews it seems that people are happy with the Delphi one. Hopefully that was not short sighted.

Besides the sending unit/pump and O ring, I contemplated straps as sometimes I see they are worse for the wear. Mine look pretty good, but I will know more when I get them off.

I will clean the grounds as suggested. It is the first one I have ever done, and I am not terribly experienced at this so if anyone has words of wisdom I am all ears. I do plan to drop the tank and not tilt the bed. I am fortunate that my truck seems to have been garaged kept prior to my buying it so I feel like this is the best approach. I've been studying at the YOUTUBE school of fuel pump removal for a period now to learn the ins and outs and I have the Haynes manuals, etc. to use a reference. One key takeaway is not to blow anything up, that I am clear on. No sparks and plenty of ventilation. No garage based fuel ignition sources.

Incidentally, in diagnosing the problem, I looked at the fuse (its good) and changed the fuel relay and fuel filter.....Figured while working on the fuel system it would be best to cover some of those bases.
 
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evilunclegrimace

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Will do, thanks for the guidance. I ordered a Delphi replacement and a new O ring to fit under the cap. Would have preferred to go ACDelco but after reading reviews it seems that people are happy with the Delphi one. Hopefully that was not short sighted.

Besides the sending unit/pump and O ring, I contemplated straps as sometimes I see they are worse for the wear. Mine look pretty good, but I will know more when I get them off.

I will clean the grounds as suggested. It is the first one I have ever done, and I am not terribly experienced at this so if anyone has words of wisdom I am all ears. I do plan to drop the tank and not tilt the bed. I am fortunate that my truck seems to have been garaged kept prior to my buying it so I feel like this is the best approach. I've been studying at the YOUTUBE school of fuel pump removal for a period now to learn the ins and outs and I have the Haynes manuals, etc. to use a reference. One key takeaway is not to blow anything up, that I am clear on. No sparks and plenty of ventilation. No garage based fuel ignition sources.

Incidentally, in diagnosing the problem, I looked at the fuse (its good) and changed the fuel relay and fuel filter.....Figured while working on the fuel system it would be best to cover some of those bases.


Having changed MANY fuel pumps/senders on these trucks over the last 30 years, tilting the bed or lifting the bed is less of a hassle than dropping the tank(IMHO)
 

kevvan

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Having changed MANY fuel pumps/senders on these trucks over the last 30 years, tilting the bed or lifting the bed is less of a hassle than dropping the tank(IMHO)

I will not question the wisdom of others, especially when they have real-world experience. I am not clear however why it is hard to drop the tank. It looks to me as if you disconnect the filler neck, tedious but not complicated, undo the straps, and lower the tank with support situated on a floor jack. Is it rusty bolts, complicated getting it back up, or some other thing I am completely underestimating?

I still have time to go another way so what is the hassle that I am not seeing. Again, remember, I am an office dweller who bought a truck and have big dreams. :)
Fast learner, stubborn, somewhat mechanically inclined, but no practical experience working on vehicles.

I should share that I have my truck on dollies so I can move it around and being up on the dollies puts it up in the air a bit so I can roll run under with a creeper. Also, it is in a garage with a concrete floor. If I were doing this on a dirt driveway I might and down on the ground I would be weighing my options.
 
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