Replace fuel pump too?

[lwarrior1016]

It shouldn’t take that long to start. We need to make sure the pump is getting power. Did you have to rewire anything for the pump?

Also, the connector on top of the fuel sending unit is known to go bad. The barrel connectors get spread out and lose contact.

 

[weendoggy]

^ My suggestion is to just by pass all the wiring crap and either direct wire (temporarily) the pump or by-pass the relay (means to use the relay Bat+ and pump lead) and see if the pump runs. If it does and you don't have pressure, try reversing the wires to the pump (at the connector) and try again. If you have pressure then, the pump was spinning backwards.

 

[Daryl]

As mentioned, the pump should run for a few seconds w/key on, or, you can bypass the relay and just run it until pressure is there. Now, it may sound like it's running and you think all is good, but, if you happened to switch wires on the pump, it'll pump, just not create pressure because it's going in reverse. I thought you had a FP gauge. If so, you can monitor that.

Now, all that aside, lets just say you have good pressure, next is spark...etc.

Just did a quick check. I didn’t hear the fuel pump prime but and FP gauge didn’t budge. Battery dropping off

 

[94IndyPace]

Looking at your old pic. The first one and the last one your fuel lines and connector are in different positions also. Are you sure your pump is in the sump area?

 

[ttocs]

just out of stupidity check the inertia switch. If it is good test the two wires on it for power for 5 secs after the key is turned on.

 

[Daryl]

just out of stupidity check the inertia switch. If it is good test the two wires on it for power for 5 secs after the key is turned on.

Embarrassingly, I don’t know what the inertia switch is.

 

[Daryl]

Looking at your old pic. The first one and the last one your fuel lines and connector are in different positions also. Are you sure your pump is in the sump area?

Not sure what pictures you’re talking about (sorry, pretty flustered; not thinking straight!). As far as the pump, it’s got to be in the sump because it sat down in the tank hole very nicely and that’s the deepest part of the tank. I doubt it would do that if it were canted one way or the other inside the tank, especially with the curvature and varying depths of the tank. Wouldn’t you say? Please correct me if I’m missing something. Thx!

 

[95opal]

I'd run straight 12v to the pump just to verify you didn't get a beat pump. If the pump kicks on with the 12v you have wiring issues ..bad pump relay or blown fuse.

 

[ttocs]

the inertia switch is the last line of defense to cut power to the fuel pump if it detects an impact from a crash. It is mounted to the back of the trunk behind the liner on the drivers side, a little box with a red button on top and two wires going in/out. If it has tripped the pump will get no power and you can see this as one wire will show 12v and one will not.

 

[94IndyPace]

Not sure what pictures you’re talking about (sorry, pretty flustered; not thinking straight!). As far as the pump, it’s got to be in the sump because it sat down in the tank hole very nicely and that’s the deepest part of the tank. I doubt it would do that if it were canted one way or the other inside the tank, especially with the curvature and varying depths of the tank. Wouldn’t you say? Please correct me if I’m missing something. Thx!

Maybe it’s an optical illusion and I’m seeing your vent hose. Like others have said, confirm you have 12v to the pump

 

[Daryl]

the inertia switch is the last line of defense to cut power to the fuel pump if it detects an impact from a crash. It is mounted to the back of the trunk behind the liner on the drivers side, a little box with a red button on top and two wires going in/out. If it has tripped the pump will get no power and you can see this as one wire will show 12v and one will not.

Sounds easy enough to check. Will do so in the morning

 

[weendoggy]

the inertia switch is the last line of defense to cut power to the fuel pump if it detects an impact from a crash. It is mounted to the back of the trunk behind the liner on the drivers side, a little box with a red button on top and two wires going in/out. If it has tripped the pump will get no power and you can see this as one wire will show 12v and one will not.

...or, it could be "ground" activated, which will show no voltage on either side. Depends on how it's wired.

 

[Daryl]

I'd run straight 12v to the pump just to verify you didn't get a beat pump. If the pump kicks on with the 12v you have wiring issues ..bad pump relay or blown fuse.

Fuse is good.

 

[Daryl]

Found the inertia switch easily enough. 2 wires into a male adapter.
And now… I’m going to voluntarily embarrass myself by asking what will seem to 99.9% of everyone, a very dumb question (but if you don’t know, ya gotta ask, right?!):

How do I check for voltage on the wires? I have a voltmeter (for just such occasions). I turn it on to 12v? Then touch both leads to one wire then do the same to the other wire? Or one lead touching one wire and the other lead touching the other wire? Which lead to which wire? Does the ignition need to be in the RUN position or no?

Sorry I’m such a dumbass with electrical, which is like speaking a foreign language to me! :-(

 

[ttocs]

put the meter on 12v and make sure it is on DC voltage, not ac. Some say DC/ac while others will have either a straight - or a ac line to designate, some a button you have to push once selecting voltage to pick ac/dc but we want dc. Put one lead to one of the wires, put the other lead to some part of the chassis or a screw that is mounted into metal is generally ok.

Now as I said you will either need a helper, or be quick to turn the key on and then verify you have 12v on both wires for 5 secs after the key is turned. Again you should hear the pump prime during this time.

 

[Daryl]

put the meter on 12v and make sure it is on DC voltage, not ac. Some say DC/ac while others will have either a straight - or a ac line to designate, some a button you have to push once selecting voltage to pick ac/dc but we want dc. Put one lead to one of the wires, put the other lead to some part of the chassis or a screw that is mounted into metal is generally ok.

Now as I said you will either need a helper, or be quick to turn the key on and then verify you have 12v on both wires for 5 secs after the key is turned. Again you should hear the pump prime during this time.

No helper available. Can I turn the key on 1st then touch wires with the voltmeter?
Or, tape the leads to the wire with electrical tape?

 

[ttocs]

you can often test a harness by simply pushing the lead up the back of the harness far enough that it makes contact with the metal and is stuck in place. As for the ground you will need to find some way to keep it attached to ground while you turn the key and then run to the meter to see if it read power.

 

[Daryl]

FWIW (just thought about it)… I used petroleum jelly in the connectors on top of the tank. Google says it was ok in lieu of dielectric grease. I now have a couple of packets of dialectric grease.
Do I need to clean out the Vaseline and tab in some DG?

 

[weendoggy]

If you have a test light, you can probe one side of the socket/wire connector and the other to ground. Turn key on...check both sides if you don't know which is hot. If it has 12v (or less) the light will light. Tada! Now, if that works, put a simple jumper across it to bypass the inertia switch. Should have light at both sides. Next move to the pump lead and test for voltage to insure it's getting there. If it is, the pump should run. Again, just because it runs doesn't mean it's spinning the correct way unless you have pressure. Simple.

 

[95opal]

Fuse is good.

Did you hit the pump with 12v?
It's the easiest way to determine if the pump is bad or the problem is elsewhere.
The inertia switches are pretty bullet proof over 35 years of owning almost a dozen mustangs I've never had one go bad.
I'd be more suspect if bad wiring or bad relay in the ccrm.