There are adapters that connect -AN lines to GM push-on quick connect, for both the 3/8" and 5/16" pump sending unit connections.

I run -6AN braided S/S lines for both supply and return, and that's in a fuel system rated in excess 0f 400 LPH.

 

Did a search on adapters, and see that underneath, I need a 3/8 QC to -6AN for the feed line, and a 5/16 QC to -6AN (?) for the return. So I don't need to mod. the lines underneath--cool.

But what about up top? Check out the pics in the link I note; can I just whack off the end of the feed & return lines and use anodized alum fittings like he did? Then run -6AN down? The goal here is to elim. the QCs up top altogether, to facilitate rerouting the lines thru that wide open space--just like he did. Will those fittings secure on a straight line? Or do they need to be flared?

 

If you want to start cutting things up at the stock fuel sending unit, your adapter would be a -6AN to 3/8” steel tubing compression fitting, and another for 5/16”. That is what was used in the photo you mentioned. Choice of adapter does not affect the difficulty of threading the lines between the body and the tank. You don't need the adapter on the end of the line when passing the line. You attach the adapter to the sending unit, then thread the open end (protected with tape) of the -6AN line through the space between the body and the tank, and attach the line to the adapter.

A compression fitting does not require a flare. As you tighten the compression part of the fitting (red part in the photo) it wedges a brass ferrule into the straight steel pipe to hold the fitting tight.

https://www.summitracing.com/parts/e...hoC3LYQAvD_BwE

I don’t recall what is on the other end of the lines. Mine were removed 20 years ago and replaced with -6AN. Looking at an old stock fuel filter, you need a quick-connect that uses the plastic pinch ring that comes with the fuel filte. The alternative would be an upgraded filter with threads to attach a -6AN male fitting, that you could attach the braided line to. I have an SX 41002 billet filter with 10 micron replaceable filter element. It fits in the stock location. Not sure is it is still available.

 

I think I'm gettin' it now. Problem was I did searches like 'convert fuel lines to AN' and got little useful info. When I search 'AN fuel line adapters' and 'AN fuel line fittings' I get somewhat more, and now that I see your post, it's much clearer.

Actually, I'm finding kits where I could make the lines myself; it doesn't look that difficult. But gotta get rid of the stock lines back there. Despite cutting the trap door over the QCs, it's still a major PITA getting them off and working w/ the lines. Kevin's solution is a big improvement.

 

All my work was done with the tank out of the car. But the tank required work to provide a connection for a second, external pump, taking suction off the low point at the rear of the tank. There’s a -10AN connection welded directly to the tank, and an internal baffle of some sort. Unfortunately when that work was being done by a shop in PA, I was 4,000 miles away working in northern Italy, so some of the details are unknown.

Just curious.... when the existing pump didn’t work with 12 volt power directly from the fuel pump prime connector, did you check to see if the pump ground was intact?

 

Not this time. Last 3 times I put a test light on the ground @ the relay, it was fine. Ditto the relay itself, but I can put my spare back in and test it again. Might as well leave that kick panel off.

 

The ground at the relay (pin 86) is for the signal side of the relay. It does not pass thru to the pump. As I recall the pump is grounded to the chassis behind the driver side rocker panel. I'll check the factory service manual.

 

Checked the FSM and while I'm no expert when it comes to schematics, it shows C405A, which is the harness connector for both the fuel pump & sender; A3/1050 is the ground. Looks like it ties into G305, which is in the rocker panel along the driver's side and under the driver's seat, and then runs up the kick panel to the relay.

Seems to me I could check for ground back @ C405A; each time I worked on the pump, that connector was removed. I sure don't wanna pull the driver seat to check G305, which has never been touched. The kick panel does run along the rocker panel, but simply removing it to check the relay wouldn't cause a problem w/ the ground. If I have ground both @ C405A and the relay, seems like a ground issue could be ruled out.

But again, I'm no expert when it comes to schematics.

 

Yes, I looked it up, and we were both looking at the same diagram. Check for ground on the black wire at the connector near the rear axle. If the fuel gauge is OK as well, you have a ground.

http://shbox.com/1/fuel_pump_connector.jpg

Then with pump side of the connector off the chassis side, check for continuity between the gray wire and the black wire in the pump harness. There will be an unknown resistance from the pump, but at least it would show there is not a break in the wires in the harness supplying the pump. Maybe pulling those fuel lines out caught the harness.

 

Yep, did all that once before; that's how I initially determined both the pump & lsu were bad. Lsu is likely good--it reads empty--but since I got it as a complete unit (hanger, sender, pump) I'll let it drain & send the whole thing back for replacement. While I'm waiting I'll get the stuff to convert the lines. Before I pull it out I'll check the relay...again...but I suspect it's still good. But wth, you never know.

 

Using the fuel pump prime connector bypasses the relay (1993-1995). You have already ruled the relay out as being the problem, if you applied 12 volts to the prime connector and did not hear the pump run

 

Waitin' on parts. Sigh...

In the meantime, checked into a 2nd pump, and specifically wanted to know the lph on the Spectra. They don't list it anywhere, but do give a flow rate of 49-59gph. Did the calcs and that would be ~175 - 220lph--enough for the hp, but somewhat less than the other options (Walbro, Aeromotive, etc.) that typically rate 255 - 340. Would it make a huge diff? Prob. not, but I'm gonna do some minor bolt-ons (eg, CAI, larger exhaust, etc.) and figure the (admittedly small) increase would be worth the marginal extra cost. So I'll pick up a Walbro 255lph and likely keep the Spectra pump for a spare.

 

I run a 208 LPH fuel pump in the tank. It easily supports 500 HP at the flywheel (0.42 brake specific fuel consumption). The second outboard 208 LPH pump only runs when the nitrous system is armed, and barely breaks a sweat supporting a 300 HP shot of nitrous (0.55 BSFC at 7,000 RPM). Fuel pump is a spot where “bigger is better” doesn’t always apply. Pumping fuel heats it up. Pumping more fuel than you need requires the pressure regulator to return a larger portion of the warm fuel which may also be hearted more as it passes hot exhaust components. It' generates more vapor in the tank. High HP cars with huge pumps often require fuel coolers to prevent heat buildup at low load/low RPM, and possible vaporization in the pump suction. A 340 LPH pump would be extreme overkill in a bolt-on setup.

 

Got all my parts (including the replacement pump assy) 'cept the Walbro, which I'll have 1st part of next week. True, a 340 is a bit much, given my setup, but a 255 isn't a problem--esp. since I've read that Walbro makes most of the pumps for other retailers. The base Spectra pump would be fine for up to ~500hp, which I'll likely never reach, but...

I was looking @ Keith's 'bang for the buck' table, and specifically the NO rig he used. That's some impressive ROI. Not sure if I'll actually do that--I seem to be getting far afield from the stock Z I was working on--but it does have considerable appeal, both in terms of HP & torque. Add that to the other bolt-ons & some mods to the tranny (ie, TC) and it would make for a good sleeper.

 

As noted in another thread, got this done. Made the lines myself w/ braided & -AN adapters--much like what KevinBlown did. Much better solution, IMO, and cost ~$80 for enough hose to do both the front & rear & the adapters. Cut the hard lines @ the pump assy., deburred & used compression fittings. MUCH easier to work the lines down thru the opening in front of the tank, and much easier to repair, should I ever need to. Heck, it was tougher getting the old lines out than it was to do the conversion.

The Spectra pump was indeed bad, despite being new--go figure. Popped in the replacement unit and tested my previous fuel line repair (see above), and there were no leaks. That Dorman kit and the push-in splicers work well enuff. But I'm not a big fan of splicing fuel lines, and prefer the braided -AN.

Now on to the exhaust...