Rotten Fuel System -- Sending Unit Question

[Penglii]

My main spring project is to rejuvenate the rotting fuel system of my 1994 Grand Prix Sedan... a decade and a half of Milwaukee slush have taken it's toll.

 

I already have a replacement tank, it appears to be a Spectra Premium... but it is in my buddy's garage 2 hours away, so I cannot immediately double check. It came from a car with 167k miles, so I don't think I'll be trusting that fuel sending assembly at all. My 1994 GP has only 92k miles on it, but I don't know how I feel about re-using that assembly either.

 

Anyway, I was looking at rockauto.com and it appears that the Spectra Premium Sender Assembly is gonna be the best price for the whole shebang.

 

Two questions though:

First off, anybody have any positive or negative experience with these Sender Assemblies (Spectra #SP09C1H or #SP09D1H)?

Secondly, how can I determine which harness code my car uses? Since I have a 1994 it appears to fall into the overlap between the 1st design (WAD) and the 2nd design (WAE)... if it helps my car rolled off the assembly line in November of 1993 or thereabouts.

 

Edit: Fixed the mileage of the car my replacement tank is from... 167,xxx miles... not 167!

[Crazy K]

you can CLEAN a good condition fuel assembly.... You can buy a can of elelctronics cleaner made by CRC at any parts store... and with a multimeter you can verify if it works.

[Penglii]

you can CLEAN a good condition fuel assembly.... You can buy a can of elelctronics cleaner made by CRC at any parts store... and with a multimeter you can verify if it works.

 

Well, that is an option I had not yet thought of!

 

How much life do you suppose that would put back into my current fuel pump? Keeping in mind that when I bought the car it had been sitting for an indeterminate number of months with only 2 or 3 gallons festering in the tank... and that on account of the rotten tank it has been run with a quarter tank or less for most of the time since August. So the current fuel sending assembly has taken quite a bit of abuse. And that is just what I know of! So I'm not convinced the pump has a ton of life left in it right now anyway... I do believe it is the factory pump.

 

Also I want to replace the level sensor... maybe if I'm lucky that will convince the gas gauge needle to float around less than it does now.

 

If you still think I can simply CLEAN the current assembly, then I will definitely consider that option.

[Crazy K]

let me try this again:

does to low mileage tank have a sender that is in good condition included?

 

as for the level float, you can clean it with electronics cleaner and test it with a multimeter, as for the tank reading varying up and down that is pretty normal...

[Penglii]

The replacement tank is actually much higher mileage... but essentially rot free.

I see I made a misleading typo in my original post, that has been fixed.

 

The replacement tank does include the sender unit... but at 167k I have no idea of it's quality or age beyond the total mileage of the car it game off of... just that I'm told it still works.

 

The next time I am able to make the trip down to my buddy's place I will pull the unit out of the new tank and see what I can see. That will either be this Friday, or the first weekend in March. Anything specific I should check on it when it is out of the tank to verify if it is good or not?

 

Either way I still need to know how to check which harness version I have... the replacement tank was from a 1995, so it is safe to say that one has the "2nd design".

 

 

[Crazy K]

could be fine. look for rust damage or wiring damage. I would use electric cleaner and then dielectric grease on the contact area of the fuel sensor.

 

milege means nothing. I reused a good high mileage tank on another car... now that tanks has 500,000+ miles, but still works.

[Penglii]

Rock on, I like the way you think!

 

I have heard that the fuel sensor is easy to accidentally break when removing/replacing/handling... any precautions I can take to avoid accidental damage to a possibly good sensor?

 

How about the fuel pump itself? Should I still replace that with a brand new one?

[digitaloutsider]

Because dropping the tanki is a giant pain in the ass, I would replace the fuel pump while you're here.

 

Unless you let a gorilla work on your car, you don't have to worry about breaking the fuel sending unit. Its just a little floater on an arm.

[3pt1lumina]

Replaced tanks/sending units and pumps on all of my cars. Some I've replaced everything including straps and filler necks, some I've just done tanks, one I did just a pump and a tank.

 

 

On your car specifically, I'd throw a pump in and be done. If you know the sending unit is shot, then replace it otherwise let it go. It's essentially up to you..it all depends how you feel about pulling the gas tank down IF the pump fails. Me personally, I don't want to take it down again for awhile.

[Penglii]

I'll already be replacing the following:

Gas tank, Tank Straps, Filler Pipe/Vent Tube, Filler Neck, and Gas Cap .

Unrelated to the fuel system I'll be doing the Leaf Spring Isolator Pads and probably coating as much of the underbody as I can with POR-15.

 

What I will do, next weekend probably, is pull the sender assembly from my donor tank to see how it's doing and how much of it I can rejuvenate. That will obviously give me a better clue about what I need.

 

Apologies for sounding like a broken record here, but I still need to know if I can tell which harness version my 1994 GP has... because of the model year it seems like it could be Version 1 OR Version 2, and I would really like to know before I drop the tank. If the only way I can find out is by dropping the tank then so be it... but I figure someone out there might know exactly when GM switched designs.