On my 1997 Z28 where can I mount a Walbro 255L external fuel pump?
The wiring I can do but How do I work the pick up?
If I don't have a sock then I have to have a filter before the pump.
How can I work this out?
I'm just cant afford to be replacing the pump every 2 years because I sometimes run the tank dry because the gas gauge reads wrong.
Thanks,

 

ideally you want to mount it in a way that is closest to the tank but away from moving suspension and behind something that will protect it from road debris.

Most hot rodders like to mount them in the frame rail which isn't an option for us with unibody cars. Mounting it to the sheet metal behind the passenger seat could work as long as it is away from the axle.

As far as the pickup you could just use the factory sending unit assembly and add your sock to the pickup tube. You will still need the sock... don't put a fuel filter before the pump, it has to work hard enough to pull the fuel out of the tank let alone through a filter!


Make sure you have good power connection going to that pump... those high volume pumps are power hogs!

 

Yea I figured this would be a big PITA.
I will have to get a stock sock and see what I can do to get the line to mount to it that way it still has easy to find stock parts.
As for mounting the pump I guess any place lower than the tank and behind the back seats.
I was thinking about mounting it right before the fuel filter but I think that's too far away from the tank right?

 

I have seen guys mount them in the middle of a car with success. As long as the pump can prime. Since you said there is a possibility of running out of fuel a lot, the closer you can get to the tank the faster the pump will prime.

 

You don't want to try and "lift" the fuel up through the stock sock and pickup, then up through the top of the support assembly, then down to the fuel pump level. Pumps don't work well when they have to "lift" the fuel. It reduces the net positive suction head, and can cause the fuel to vaporize in the suction line, from the reduced pressure. When the pump shuts off, the fuel may also run back into the tank, leaving an air bubble in the suction line.

You want the pump suction below the fuel level. That's why you use a "sump" at the low point of the tank. There is always fuel above the pump, providing a positive pressure rather than a negative pressure. You also want the pickup point toward the back/bottom of the tank, so the fuel is pushed toward it under hard acceleration.

Rather than remove the in-tank pump, then cobble up an external pump without the correct configuration, why not just fix the fuel level gauge, and be a bit more careful when you know the tank is approaching empty?

 

OK let me see if I have this right.
If I take the old fuel pump out and fab up a new pick up with a sock on it then put an external pump I guess right where you have yours on the driver side behind the back seat that would not work well because I need to have a sump put on the tank?
If that is the case then I have know idea how to fix the sender to make the gauge read right.
Last time I had it down I looked at the sender the float was good and it moved all the way up and down.
It seams that it has gotten worse over the past 2 years.
I think I said it in my first post but the gauge was 1/8 of an inch from the E line and I was on my way to get some gas when it died.
At this point it's not about the time in dropping the tank it's the 100-120 bucks for the new pump and sock.
God forbid I got a GM pump for $500 bucks or a regulator aftermarket pump for around $250 that comes in the bucket.
If you have any ideas let me know I have been out of work for more time than I want to say and the money I have is drying up.
If I could find the whole fuel pump and sender at a salvage yard I would give it a try but the pumps get tossed when they take the gas out.
I remember that a friend of mine was working on a Firebird just like yours he had a carb on his engine and he took the tank down made a pick up and ran an external fuel pump and that car never had any fuel problems.
Could it be different because he was running a carb than FI?

 

Did you use Shoebox's guide to check the fuel level issues?

http://shbox.com/1/4th_gen_tech2.html#fuel_gauge

The -10AN (5/8") suction line for my outboard pump comes off a connection at the bottom/back of the tank. There's a baffle and a screen inside the tank. The stock fuel line coming out of the tank support assembly is only 3/8". I also have another aftermarket pump in the tank, in the stock location/stock bracket. The outboard pump only runs when the nitrous system is armed.

http://www.injuneer.com/images/photo.../DCP03576a.jpg

You don't need a $500 stock fuel pump. You don't need a $250 pump with a bucket. You can get a Racetronix 255 LPH pump that fits in the stock bucket for $150.

 

Nope I did not know that Shoebox's web page had that.
I have the tank out right now so I'm not sure if you can still check it because it's not at the same angle.
I found out today that I can get a Walbro 255LPH Model: F20000169/400-1016 that has the offset intake like the stock one had for $80+tax.
So that's not bad but If my gauge is reading off and I run out of gas I will burn up this pump to and be right back where I am now.
So what do you think I should do on the cheap to fix this problem?
Thanks,

 

Just be careful...... there have been a couple of alerts recently regarding counterfeit Walbro pumps being made in China.

To check the sending unit, all you have to do is have the complete fuel bucket in your hand, harness unplugged. Let the float drop to the bottom and move it SLOWLY to the top, watching to see if the resistance moves through the values shown in the table. You may have a flat spot or dirt on the winding, and it may have a sudden spike in the resistance.

 

OK I'm going to check that today after I suck out the 3 gallons of gas I put in thinking I was out.
Yea I Have read about the Walbro pumps thanks.
You never answered my question about the Sump.
For a street can do I really need a sump to run an external pump?
I don't understand why I could not extend the pick up and run the external pump like I the car my friend worked on.
And that car has no fuel problems with a external pump.
BTW what ohm's scale should you use?
I have 2000k,200k,20k,2000, and 200 on my cheap multimeter.
I'm going to sat to use the 200 scale.
Let me know.
Thanks

 

Just checked the sender I got 114 ohm's all the way up and 19 ohm's all the way down.
So that makes sense the gauge read above F and does not read E when empty.
So if I run it to 1/8 of a tank then I will burn up the pump agine.

 

Cutting the fuel pump access hole allows you to change pumps in minutes; basically as quick as an enternal pump, and not poop.

Surely you haven't removed the intank pump's bucket..?

 

I have the tank out and the fuel pump and bucked out of the car now.
I'm just trying to figure out what to do like a said before I don't mind taking the tank down.
I just can't afford to be replacing the pump every 2 years or so.
If I can't get the fuel sender to read right I want to make sure that I don't burn out the pump.
It would seam if I put and external pump it would not burn out when and if I ran out of fuel.
If the pump dies I have to have the car towed at least 55 bucks plus a new pump and sock but if I only ran out gas it would be way cheaper.

 

Not sure what more info you need. I recommended you need to take the external pump suction from the bottom/rear of the tank, and I explained how I did it.

If you want to do it the way your friend did it with his carb setup, go ahead and do it. I told you everything I know, and that's all I can do. If you don't agree, so be it. And I'm not sure why your so irritated because I "never answered your question about the sump"... I tried.

Good luck.

 

No I'm not irritated.
It just sounded like I had to have a sump on the tank for the pump to work right thats all.
I just kinda got lost there and did not understand what you were recommending I do.