Z34 fuel pump differences?

[NCTyphoonKid]

Is there a difference in the harnesses for z34 fuel pumps? My gauge is off and I plan on putting a new sending unit in when I drop the tank and noticed rockauto lists two different ones, is the difference just wiring or is there more to it? Is there a easy way to tell without dropping the tank first?

[digitaloutsider]

Maybe you can get up under the car and see if you're lucky enough to still have a wiring harness tag on it? The difference seems to be one is 4 amp vs 6 amp. 

Since RockAuto lists the OEM part numbers, you could probably go to the dealer and see which one they say is right and go off that. Sometimes you'll see a VIN # reference for midyear changeovers like that, but I can't find one anywhere.

[NCTyphoonKid]

I’ll see if I can crawl under it and look, the pump is getting weak I believe I have to step on the gas a little to get it to start now and with the gauge being wonky I’ve about ran it out of gas twice so I’m sure the pump is getting close to being toast, and I’m not sure how old it is anyway. But even before I did that it would take 2-3 starts to finally get it to run.im assuming from age

[Imp558]

I wonder if a dealership would be willing to give you the P/N based on the VIN..

[NCTyphoonKid]

I slid under it tag was still in perfect shape I had a WAE one. So got the replacement pump, sending unit and fuel filter on the way. Going to try running it down on gas in the next couple days and get it ready for replacement.

[Imp558]

First Gens aren't horrible to drain. When I did it I lowered the tank on my transmission jack just enough to get the fill hose/vent hose thing off and got a siphon going.

 

Tank straps are cheap enough to make them not worth using again unless they are in exquisite condition.

[jiggity76]

I slid under it tag was still in perfect shape I had a WAE one. So got the replacement pump, sending unit and fuel filter on the way. Going to try running it down on gas in the next couple days and get it ready for replacement.

Good deal!  I'm guessing that my 91 LQ1 will have the first design WAD code then, good to know.  Let us know how it goes, I'm suspecting my fuel pump is dead on mine.  Also curious to know how loud the pumps are.  I replaced a pump on my 97 Silverado and it was pretty buzzy until it got some miles on it.

[vipmiller803]

I routinely do this over the phone and they never give me grief about it.

I wonder if a dealership would be willing to give you the P/N based on the VIN..

[NCTyphoonKid]

Believe it or not pretty much everything under the car is in super shape minus the rear bumper support it has some rust but I’ve got a replacement put up

[Schurkey]

Going to try running it down on gas in the next couple days and get it ready for replacement.

The pump still works.  Form a tube, pop the hose at the fuel filter, cram your new tube into the hose, use the fuel pump to move the fuel out of the tank into a suitable container or three.

 

 

[Imp558]

The pump still works.  Form a tube, pop the hose at the fuel filter, cram your new tube into the hose, use the fuel pump to move the fuel out of the tank into a suitable container or three.

 

 

 

Wow, that's pretty cool, do you have a P/N for that flare kit or a comparable one? I take it personally as a legitimate tool junkie that I don't have one yet..

[vipmiller803]

I've done something similar in a jeep but under the hood. Easiest way to drop the fuel level without waste. On another note: I am always reluctant to just replace things "while I'm there". I was faced with this decision when my sending unit rusted through and leaked gas everywhere. The pump was fine. I decided to just keep my pump. Years later, 60k and the pump is great. The biggest pump destroyer is running low on fuel constantly. They really live a long time, so why chance an aftermarket unit?

[Schurkey]

Wow, that's pretty cool, do you have a P/N for that flare kit or a comparable one? I take it personally as a legitimate tool junkie that I don't have one yet..

https://www.amazon.com/Mastercool-71475-PRC-Universal-Hydraulic-Flaring/dp/B007TN15EG/ref=sr_1_17?ie=UTF8&qid=1527308662&sr=8-17&keywords=Mastercool+flare

 

Mastercool 71475 is what I have, then I purchased the 37 degree flare add-on kit.  The GM fuel tubing crimp dies are included with the 71475 set.

 

It may be that Mastercool 72475 replaces the 71475 set.

https://www.tooltopia.com/mastercool-72475-prc.aspx

[Imp558]

Pretty expensive but just being able to make 1 piece fuel lines from rolled tubing would be freaking awesome.

[mfewtrail]

Another option to remove the fuel from the tank:

 

1. Relieve fuel pressure.

2. Use a valve core tool to remove the core from the fuel schrader valve.

3. Clamp a piece of fuel hose over the fitting and run the other end into a gas can.

4. Use the factory supplied fuel pump test lead near the battery to run the pump and move your fuel from the car tank to your gas cans.

 

 

 

 

@ Schurkey - Are those goodyear Viva 2's I spy? A lot of people shit on goodyear tires, but I've had several sets of those that have more than surpassed the rated mileage. They rode fine and were quiet as well.

Edited May 28, 2018 by mfewtrail