HwyStarJoe

Hi all,

A quick background of the issue...
Fuel tank has the Supply and Return braided lines from the in-tank pump routed thru rubber coated clamps along the underside of the trunk to the fuel pressure reg\filter mounted there, then on up to the front of the car.

One or both of the AN fittings on the braided\PTFE lines supplying the regulator leak. It could be the regulator itself... I don't know for sure. The single line leading forward does not leak.

As I had the car running in the garage the other day, I slid under there to investigate and I wiggled the two lines that are run side-by-side together thru the clamps to the regulator to see if I could make the leak worse or decrease it. As I did, the engine started to sputter as if loosing power and then quit.
I made this happen once last year doing the same thing, but the engine didn't quit.

It seems there's a ground issue or something electrical happening between the reg. and the fuel pump (Walbro 255) when the two lines from the pump touch. But that's very odd because they're run together and touching all the way to the reg. I think it's only when the fittings AT the reg are moved that this loss of power occurs. The reg is grounded to the body.

The issue is that the fuel pump will not prime or run now, but all of the fuses are good. And the car won't start but has power. The starter clicks, and the battery is good.

I have the fuel pump and AUX fuse panel on separate breakers in the trunk by the battery as shown in the drawing, using the type of breakers in the picture.
(Unlike the diagram shown, there is no separate battery block... the power feeds are directly to the battery + post.)

Do these breakers auto-reset? I haven't had time to troubleshoot other than to make sure all fuses are good so far. I'm going to start at the fuel pump relay to see if there's 12V there with the key ON and work my way forward. But if the breakers don't auto-reset, I guess I'll know why the car doesn't start.
Then I have to figure out why moving the regulator fittings kills the car. That's what scares me... it's possible the power and fuel sender wires are pinched between the trunk floor and thee tank.

Thanks all... I need to get the car to the tuner and get ready for the Power Tour.

Old Geezer

iTrader: (3)

Unless those breakers have a reset button on them, they would be auto reset.
As for the ground issue......
If that car is a unibody, and the batt is grounded at the rear body, and there is a poor/no engine ground to batt, u r using the braided lines as a ground cable.

Tanus

Current flowing a mm from cumbustable gas that sounds within OSHA specs, lol, id have to agree, current take path of least resistance so because your, im thinking, engine ground sucks its having to use ground current down your lines then grounded where you put the regulater, I think if it wasn't grounded it'd follow the lines to tank and use your fuel pumps ground which is probably what's happening when you play with the lines causeing the sputtering dying, you may have destroyed pump but id address grounds first and then worry about pump

Tanus

Oh id guess leaks are where the current melted the inner rubber lines, or your just not good at putting lines together,jk

HwyStarJoe

Thanks all...
I've got multiple and excellent ground straps from engine to body, and engine to frame. All clean and bare metal.

The Batt. ground is to the rear frame rail, which is part of the trunk floor\body.

The portions of the fuel lines that are not hard line are braided PTFE. Admittedly it was my first attempt at making them so its entirely possible I got a strand or two caught between the AN parts. I expected to have to re-do at least one of them.

If moving the lines causes some type of grounding or circuit interruption, I can't think of any other way to run them to the regulator other than to run them separately from the pump, and wrap one of the fittings at the regulator with insulating tape.

If its truly an issue of the fuel line(s) acting as a ground path, how can running a dedicated ground from the engine to the battery prevent it? Its easy enough to do.

I'll know more tomorrow now that the yard work is done.

Pop N Wood

iTrader: (1)

This is the reason why I preach to never use body panels to carry current. Always run two wires to every load. The domestic auto makers all thought they could save a couple of bucks by not using ground wires. This is part of the reason there are so many imports in the US. Back in the day when a car only needed to last 8 years or so it was good enough. But now nobody does it that way anymore.

Have to agree with old geezer, sounds like your fuel lines are carrying power.

Run dedicated ground wires to the fuel pump and hook the battery negative straight to the block with the same gauge wire that you use on the positive side.

By the way, PTFE tubing is purposely made conductive to shed static electricity that can form when fuel flows through it. If your connectors aren't spot on then you can have an intermittent connection.

Old Geezer

iTrader: (3)

What pop said^^^^^^^^
It may be that the ground issue is only w/ the pump/hanger.
Gas gauge work accurately?

HwyStarJoe

The fuel gauge works fine. I don't have any electrical issues with the car other than when I moved those two lines at the regulator the other day.
I've had the car on the road for a while and it's never hiccuped while driving... it's odd that this would manifest itself so easily while sitting still.

I plan to increase the my grounds from the rear to the front, and add one straight to the engine from the Batt. Maybe increase the ground from the sender and pump also.

As far as the 2 fittings leaking that lead to the Reg. and not the one leading forward from the Reg., I would think if this power\GND issue were the cause that all 3 would be leaking.
I wish now that the tank wasn't full. I love working upside down with fuel pouring on me.

HwyStarJoe

Finally had time to investigate...

The two lines leading to the reg are not grounding. But the supply from the reg to the hard line on the frame going forward is. That makes the regulator grounded.
I don't think it should be because the regulator bracket is insulated from the reg itself.
The hard line and then braided section at the engine are not grounding.

I don't have any stray voltage anywhere. The fuel pump still won't prime, but now the electric fan comes on with the key on and the engine is stone cold! WTH? That shouldn't happen till 180 degrees.

If the fuel line from the reg to the engine should not be grounded, I don't understand because I'm sure there are plenty of swaps running around that use non-insulated fuel line clamps the length of the car.

Gonna play with it till I run out of patience. .. The Masters is on.

1989GTA

"Run dedicated ground wires to the fuel pump and hook the battery negative straight to the block with the same gauge wire that you use on the positive side."

For those running ground wires that is the recommended way to prevent ground loops. Battery negative to the engine block. Then from the block to the chasis and from the block to the frame.

Tanus

I'd check the fan wiring(while your at it add the dedicated ground to it and fuel pump and if you have have any other high draw accessories those too. sounds like the fan relay wiring may be where the short is. the cause of that short being the weak main ground

HwyStarJoe

Slight update...

I don't have any ground issues. The way its wired and grounded is fine... no need to change anything. If it ain't broke don't fix it.
But I believe I figured out what killed the fuel pump, but haven't confirmed it yet. I think that when I moved the leaky fuel supply and/or return line, I introduced enough air into the pump to kill it. I've got no electrical issues with the fuel system.
The fan coming on is a different and totally coincidental issue. Now it works as its supposed to.
Time to drop the tank and buy another pump. I KNEW I should have built an access panel in the trunk when I did the swap!!

HwyStarJoe

I take back what I said...
I finally dropped the fuel tank so I could rebuild one of the AN fittings with a pesky leak, and test the fuel pump.

Turns out the shop that came recommended to do my exhaust really isn't a place that should EVER be recommended. I won't go thru the long list of things they damaged or screwed up, but one of them was to damage the fuel pump ground wire. I found it hanging by one conductor. Seems it was cut... not frayed or chewed by a mouse. Cut. Not to mention the weld slag burn I found on one of the braided lines.
I don't know how they did it, but the wire finally broke while I was looking for that leak the other day. All is good now.

Never let a guy work on your car when the first words out of his mouth are "Where'd ya get this, eBay Special?" when he see's the expensive, custom-fit Magnaflow exhaust system you'd like installed.